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So hello everyone, welcome to the session. So let's get into the class and start the class. Class time is over.
Good evening to everyone. Let me know if my voice is still there. Let's start with the questions. There is a technical issue today. MCQ will be there and today there is a technical issue.
All clear dear? Let's start guys. Today's series and telegram channel is Rahul Mishra Sir Testbook and Testbook Engineering. You will join it soon. So Testbook Engineering and Rahul Mishra Sir Testbook you will join both of them.
Here you will get a lot of advantage. That means you will get all the class PDFs available here. And guys Testbook is giving you a very good offer. We are going to cover the questions of RRBJ's thermal engineering.
In which we are going to cover all the questions of Thermodynamics, RAC, Power Plant, IC Engine. All the questions are going to be covered here. Good evening to everyone.
So guys lets start today's video and before that I will tell you about preparation flight test book Yes dear it looks a little different because today there is some technical issue That's why class is taking like this so I hope you all will cooperate So preparation flight sale is available from 5 to 7 May And selection take off means you know that If you guys want to study a full detailed structure of the course and you want to select by reading Means you want to clean good number, get good rank in exam and score well then you definitely You have to go through a process to get the knowledge of the subject along with MCQ and technical knowledge. So guys, the test book given in the middle is AGE mechanical course at 90% discount and also you are getting 2 months extra validity i.e. 33% extra validity. You are getting AGE mechanical course of 11000 in 2989. You just have to use the code R.MISHRA.
What code you have to use? You have to use the code RMISSRA. So guys, you will use this R.MISHRA code and you will get this full advantage here. And if you want to prepare for Bar Category 1 & 2 So guys we have the full course of Bar Category 1 at 90% discount Course of 7000 in 1819 33% extra validity Offer is only for 7 days You will not get this offer after today If you want to take off then Selection take off and selection fly off If you want to give the exam of Category 2 of ITI trade in Bar Then we have the full course in detail for that You are getting it at 90% off 33% extra validity Course of 6000 in 1559 6 plus 2 months means with 8 months validity offer is only till 12pm today you have to apply the armishra code and it will be completed so guys if you want to take off in reality then make this course your own put my code armishra and make this course your own and get ready and guys keep in mind that its last date is only today after that you will not get this course so before this offer is over make this course your own and lets start today's session Good evening dear Is the audio good? No problem Mr.Rachit Sharma That's good Ok dear Can't you see me?
I can see you Let's solve the question and answer it. I am getting tired of watching this Good evening, good evening dear, good evening Which of the following engine will have the heavier flywheel than the remaining ones? Guys, in this video we are going to cover the questions of IC engine, RAC and power plant thermodynamics So you all will come here I have made myself small because the questions are big sometimes So if I make myself big then the question will be hidden from the back So I have made myself small which engine will have the biggest flywheel and heaviest flywheel so guys that will be your see what is the type of flywheel you want heavier the engine with less speed the engine with less speed you want heavier flywheel the engine with more speed you want smaller flywheel so you know that the speed of diesel engine is less so the speed of petrol engine is more so we remove petrol engine remove petrol engine because we want heavier petrol engine has more speed and flywheel mass should be less If the speed of the petrol is high, then the mass of the flywheel will be less. If the speed of the engine is low, then the mass of the flywheel will be more. Now, the question is about diesel and petrol.
Two-stroke diesel and four-stroke diesel. So, kids, understand that both have the same speed. Both are running at 750 RPM.
But in the two-stroke engine, the torque is more uniform. Why? Because you are getting power once in every revolution. In four-stroke, you are getting power once in every two revolutions. That is why we use small flywheels in two-stroke.
And we use big flywheels in four-stroke. diesel engine both have same power 2 stroke diesel engine running at 750 rpm 40 hz 4 stroke diesel engine running at 750 rpm ok so which one we will use guys we will use 4 stroke 4 stroke diesel engine very good next question yes, young people are the history correct ok dear, we will answer fast In this all are combined IC engine power plant RAC thermodynamic all are combined So answer quickly and we will do it in rapid fire Let's answer this Consider the following statement Knock in SI engine can be reduced by How can you reduce knock in SI We will answer quickly And once again like the live session and share with your friends So that they also know that the class is over Start So let's see that you have to reduce knocking in SI engine So I have told you many times that what are the parameters of SI engine If you want to reduce knocking in SI engine Then you will increase the velocity You will reduce the load You will reduce the load and increase the velocity You will retard the spark You will retard the sparking You will do all these And what will you do dear Your ignition lag will be higher What should be the ignition lag? It should be higher you will use fuel of higher octane number you will use fuel of higher octane number you will do all these things good evening everyone good evening so guys you are using a fuel of long straight chain structure this is wrong you will not use this you will use crossed chain structure because the fuel which is in long chain structure like CCCCC in straight chain their octane number is less and they promote knocking but here you have to reduce knocking So supercharging is not an option.
Supercharging is an option in diesel engine. So you will do retarding the spark and increase the speed of the engine. So option 2 and 4 means option D will be corrected.
Let's go to the next part. Yes, you will increase the ignition lag. And if it is about diesel engine, then you will decrease the ignition lag.
Let's go to the next question. Let's answer it fast. The injector nozzle of CI engine is required to inject fuel at a sufficiently high pressure in order to Tell me, everyone will answer quickly The injector nozzle of CI engine is required to inject fuel at a sufficiently The injector used in your nozzle, in diesel engine It is required to inject fuel at sufficiently high pressure It is required at a very high pressure to inject fuel Why do we do this? option A is correct option A is to be able to inject fuel in a chamber of high pressure at the end of compression ratio means as soon as compression process ends I am telling you Deepak, don't worry as soon as compression process ends fuel will be injected at high pressure so that proper mixing is done and ignition lag is reduced inject fuel at a high velocity to facilitate atomization if you inject fuel at a high velocity then atomization will be proper ensure that penetration is not high penetration is not high is wrong Penetration high means Penetration means Like your injector is here And your clearance volume is here And this is your air fuel mixture This is your air fuel mixture Penetration high means It should reach deep So that fuel can mix properly So piston is here Piston is here.
So, this fuel should come from high pressure and go inside. As far as fuel is there, the clearance volume should reach its bottom so that mixing is proper. If mixing is proper, then ignition lag will be reduced.
So, penetration should be high. Not high is wrong. So, penetration high means option 1 and 2 will be there.
Next math. Okay. Yes, reach the goal.
Very good. Consider the following statement regarding NC10. Which is the truth about normal C10? We will answer it fast.
We will try to solve the question quickly. We will answer it quickly. Which is the truth about normal C10?
Very good. Let's go. Which is the truth about normal C10? Gajtandji is saying A.
Amanji is saying A. Rachi Sharma ji is also saying A. So let's see if A is correct.
Yes. It is standard fuel for NOC rating. Absolutely correct. We do NOC rating with normal cetane. Normal cetane is called normal hexadecane.
That is C16H34. Its chemical formula is C16H34. And we add one more thing in it. Which is C11H10.
We add one more thing in it. Which is C11H10. And I think this is called alpha methyl naphthalene.
alpha methyl neptaline neptaline So C16H34 is a saturated hydrocarbon means single single single single bond because it is of methane group sorry not methane but of alkane group C16H34 CNHN plus 2 so this is saturated hydrocarbon not unsaturated, not double bond it has long carbon chain structure this is wrong C16 is not like that all are connected with carbon lines 16 are connected with carbon lines these are in crossed chain some are connected with carbon lines remember one thing whether its SI or CI engine if it is in straight chain it will increase knocking if any fuel is in straight chain it will increase knocking if it is in crossed chain it will not increase knocking option 4 is wrong option B will be correct The method of determination of indicated power of multi cylinder SI engine is the by use of Now you know the answer to this question. It is a very easy question. So what will happen?
Modes test. Now see modes test. They are for multi cylinder engine.
Whether it is CI engine or SI engine. Listen carefully. Whether it is diesel engine or petrol engine. The condition is that it should be multi cylinder.
If it is SI or CI or multi cylinder. Then you can say indicated power or frictional power. Both can be calculated Now let's talk about the PRAWNY BRAKE TEST This is a different thing Our motoring test is for Frictional Power Motoring test is for Frictional Power of Single Cylinder Engine Single Cylinder Engine Let's come to the next question In this you have to tell Decreasing Order of Remember it is decreasing order Decreasing Order of Brake Thermal Efficiency Decreasing Order of Brake Thermal Efficiency Good evening dear What is your name? Has anyone given you this name?
Keep it to yourself Has anyone given you this name? Yes dear, Prawnee Brake Dynamometer Prawnee Brake Dynamometer What do we use this for? Prawnee Brake Dynamometer, Rope Brake Dynamometer These are all dynamometers that we use to extract brake power Next question Decreasing order of thermal efficiency Yesterday's master class timing Somgoji, I will message you in group.
I will message you in group. A for ALP. Very good. A for ALP and D for D group. A for ALP and D for D group.
Okay, kids? ALP is also D group's job. So, A for ALP and D for D group. So, you can answer any question.
See, the most thermal efficiency is of diesel engine. Diesel engine has more thermal efficiency. From which?
From petrol. Diesel engine has more thermal efficiency than petrol. Because diesel engine has bigger size of cylinder. you can see here 4 strokes C I engine after that 4 stroke petrol engine and less than that thermal efficiency 2 stroke petrol engine after that 4 stroke diesel engine after that 2 stroke diesel engine after that 2 stroke petrol engine so you can write 2 stroke ci see i have given you all 4 stroke ci then 4 stroke si then 2 stroke ci then 2 stroke si This will be your proper order, maximum of this and minimum of this minimum here and maximum here ok, let's move on to the next ALP vacancy will come, what to say Only one option is correct, Ramesh ji where are you lost Only one option is there, option A is correct D option is not correct, I was saying that D group's job is ALP Only one option is correct Wow, life is a journey, and life is a journey, Suhana.
Who knows what will happen tomorrow? Tell me. So, kids, what do we measure brake horsepower with a dynamometer?
It will be 3. What do we measure engine speed with a tachometer? It will be 2. What do we measure calorific value of fuel with a bomb calorimeter? It will be 1. What do we measure bomb calorimeter with?
Solid and liquid. solid and liquid fuel what is the calorific value of the fuel? bomb calorie meter ok and the flame ionization detector what is the emission of exhaust? the emission of the exhaust of the vehicle what is the content of the exhaust?
what is the emission of the very good in practice the efficiency of diesel engine is higher than the petrol engine for the same compression ratio the efficiency of diesel engine is higher than that of auto cycle so the question of assertion and reason is which one is right and which one is wrong lets see what answer you guys give Dubey ji is saying C will be right C will be right lets put C group C group should be applied In practice Efficiency of diesel engine is more I told you earlier that Diesel engine efficiency is more Assertion is correct Because diesel engine cylinder size is bigger And if someone says Both cylinders size is same If both cylinders size is same Then petrol will be more Why? If both cylinder size is same Then petrol will be more efficient Because petrol is eating better food Petrol engine has better ignition quality than diesel engine That means it has more calorific value than diesel engine If calorific value is more than diesel engine then it will generate more heat If more heat is generated then it will generate more brake power If indicated power is more than indicated power then it will generate more brake power If two engines have same frictional losses If cylinder size is same If piston size is same then almost friction will be same If both cylinders have same size If frictional power is constant Then the indicated power will be more and brake power will be more And thermal efficiency will be more For the same compression ratio, the efficiency of diesel is wrong. Don't lie so much. Option C will be corrected. Next, let's go to the next.
Thermal efficiency, dear. Thermal efficiency. Yes, dear.
Its reason, air fuel ratio. Air fuel ratio. Tell me one thing.
What does it mean by compression ratio is high? Compression ratio is high means air fuel ratio is expanding till far Compression ratio is high means expansion stroke is high If expansion stroke is high then work done is high One of the important requirement of the carburetor is to supply lean mixer at starting The rather lean mixer is required at no load and part load condition Option D will be correct Option A is wrong Carburetor's work is not to supply lean mixer The function of the carburetor is to supply air fuel mixture as per the requirement. The function of the carburetor is to supply air fuel mixture as per the requirement. It is not like a lean mixer. It is to supply as per the requirement.
It will supply when it is needed. So, option D will be correct here. Rather, lean mixer is required at no load and low load condition.
It is very correct. If there is no load and low load condition. For example, I will tell you that diesel engine.
like i am telling you diesel engine if diesel engine has no load condition suppose this is diesel engine If there is no load condition then air fuel mixture is approximately 80 to 1. Air fuel ratio is 1 part fuel and 80 part air. Air fuel ratio is 70 to 80 to 1 on no load condition. And low load condition means if I say that there is part load condition.
If there is part load condition then it is 18 to 1. How much is 18 to 1 on part load condition? No, sorry. No 18, 35 is to 1. How much is it?
35 is to 1. On which is 18 is to 1? On loading condition. When load is more on it, then 18 is to 1. And if it is part load condition, then 35 is to 1. So D is absolutely correct answer. Next question. Tell me.
Consider the following statement regarding auto cycle. Those who are new, quickly answer. Quickly. Which is the truth about the motorcycle? Hurry up everyone Ok So what will be the option?
It will be de-corrected Why? See The first statement about the Auto cycle is that it is not a reversible cycle. So this is wrong.
What is an Auto cycle? It is a reversible cycle. What is an Auto cycle? It is a reversible cycle. What is an Auto cycle?
It is a reversible cycle. So option 1 is wrong and 1, A, B, C are in all three. So all three will be wrong. Because 1 is in all three, so all three will be wrong and option D will be correct.
Come on. Its efficiency can be improved by using a working fluid of higher value of ratio of specific heat. That means if you want to increase the efficiency of Auto cycle. So you can increase the efficiency of the fuel with a higher specific heat value Because the efficiency of the auto cycle is 1 by r to the power gamma minus 1 Now you know that if you increase the compression ratio, then the efficiency will increase And if you increase the gamma value, then also your efficiency will increase So this option is absolutely correct Let's come to the next D for group D Explain option D Very good Vikash, let's go carbureted gasoline engine working on auto cycle can work with compression ratio more than 12 see dear, this means that many students are confused now I will show you what this means I think you know, no problem give me one second, just give me one second ok, see what is carbureted, see, what you know is that the compression ratio of petrol engine, dear, from where to where this is almost, almost between 5 to 10 or in your book 6 to 10 is written you can take 6 to 10 between 6 to 10 is compression ratio why we don't increase compression ratio in petrol engine because if you increase compression ratio in petrol engine then a very big problem will come which is knocking if you increase compression ratio in petrol engine then knocking problem will come here so how to solve that knocking problem either you increase compression ratio in petrol engine when there is no knocking Because increasing compression ratio is not beneficial.
If you increase compression ratio, then efficiency will increase. But the problem is of knocking. So, we have to save knocking. If we are increasing compression ratio, then our efficiency is increasing. So, we want to increase it.
But we are not able to increase it because knocking is increasing. So, we take a fuel whose octane number is very good. If the octane number of that fuel is very good, then our knocking will be less.
So, we will go to compression ratio 12. Then also, knocking will not happen. And efficiency is increasing. So, the same fuel is left.
What is that? Carbureted gasoline. Carbureted gasoline Which is called high speed petrol Kind of high speed petrol Which has octane number 95 If you take such fuel Then even if you increase the compression ratio Then also there will be no difference So this is the answer I hope you understood Vikas ji are you clear Very good fast guys consider the following emission of IC engine which one of these makes photochemical smoke which one of these makes PCS which one of these makes PCS A class officer who will make A class officer who will make A class officer PCS so kids Hc and NOx hydrocarbon and NOx this makes PCS Photochemical smoke means a hazy environment A brownish environment Like today I was coming from Gurgaon So there was a hazy atmosphere on the way So that is kind of photochemical smoke Which contains a lot of NOx and hydrocarbon mix And the sensation in your eyes is burning When you come out in such an atmosphere You feel that your eyes have turned red So if someone sees you And you come out like this If you suddenly come across your dad in a photochemical smoke environment, your dad will ask, where are you?
Why are your eyes red? Have you eaten a lot of food? Why are your eyes so red? Where were you?
Where are you going? So this is called photochemical smoke. So tell your dad, no, we don't eat a lot of food. We don't do drugs. It's a bad thing.
This is photochemical smoke, dad. This is kind of photochemical smoke. Pops. Pops, this is kind of photochemical smoke. So what is it?
Two and three. Let's move on to the next part. Okay. This question is good. You guys have answered this question many times wrongly.
Don't do it this time. So this is going to be an important question. Hey, you guys laughed so much. You laughed so much. No, we didn't go to eat chole putra.
Good evening, good evening, good evening. Okay, so answer it quickly. Okay.
Velocity of flame propagation in SI engine is maximum for the fuel-air ratio, which is Now kids what is this? Fuel Air Ratio Now keep in mind when this happens Which is 10% richer than Stichometric Now Stichometric Fuel Air Ratio See what is Stichometric Air Fuel Ratio? What is Stichometric Air Fuel Ratio?
Air Fuel Ratio Stichometric Air Fuel Ratio is 15 is to 1 Approx in which? In Petrol Engine So what will be the Fuel Air Ratio? Fuel Air Ratio will be 1 by 15 Will be done If it is 10% richer than this, if the fuel-air ratio is 10% richer than the stoichiometric, 10% richer, rich means the fuel is a little more, fuel-air ratio is rich means the fuel is a little more.
If the fuel is a little more, then the flame propagation will be maximum in SI engine. But if it is more than this, if it is more than this, if you say that sir, if it is more than this, if it is 25%, if it is 25%, it means that the fuel is a lot more. and the air will be very low if the fuel air ratio will increase a lot then the fuel will increase and the air will be very low if the air will be low then the turbulence will be low if the turbulence will be low then the flame propagation will be low because of this you can't use the fuel air ratio very much so the option will be that you will use only 10% tricher than stoichiometric yes you are right, you are right you said this right you are very nice question 10% richer than a Strychometric and more than 10% richer than a Strychometric Both are very different Who is asking?
Usha Kiran Ji is asking See there is a lot of difference 10% richer, suppose Strychometric is 100 Strychometric is 100 so you have to use only 10% Means 110 10% more than More than 10% More than 10% means more than 110 You don't have to go more than this Because if you go more than this, see what is the ratio? Fuel Air Ratio If you take more than this, then the fuel will increase. If the fuel ratio is too high, then the air is decreasing. If the air is decreasing, then the turbulence created by the engine is air. And if the air is reduced, the turbulence is reduced, then the flame propagation will also be reduced.
Because of this, we use only 10%. And this is the official question of UPSC. This is the question of CSC Pre. Civil Services Examination Pre.
Next pattern. In a variable speed SI engine, the maximum torque occurs at maximum. Answer.
Yes, it is. You are very nice question. But your question hurt me.
Yes, yes, absolutely. Renald, you can do anything. Renald, see, when you do Twitter campaign, when you do Twitter campaign, then keep a little attention that your viscous force is a little more. Because if you are from UP, then UP police is not there at this time. the inertia force is increasing a lot so try not to increase the number of reynolds your viscous force should be high because UP police will increase the inertia force so try to understand the tweet as well in a variable speed SI engine the maximum torque occurs at maximum torque occurs at maximum brake power what is brake power?
torque into omega. So, if torque is more, then when is torque more? That means, when brake power is more, brake power, power is equal to torque into omega, then torque is more. When will maximum torque be?
When your brake power is maximum. See, what will be torque equal to? BP by omega, will it be or not?
If brake power is maximum, then torque will be maximum or not? Absolutely right. Let's go to the next part. So, guys, this is a gas engine whose swept volume is 300 degrees Celsius.
How much is it? 300 cc. First, I'll increase its entropy.
How much is it? 300 cc. Its swept volume is 300 cc. Okay.
And you... Wait a minute. What should I tell you?
300 CC and clearance volume is 25 CC. Volumetric efficiency is 0.88 and mechanical efficiency is 0.9. Volume of the mixer taken in per stroke. Tell me. 252. Very nice.
252. Very nice. 252 will come. Simple thing. Why are you answering 264?
264 answer. Why are you answering 264? 252 will come, right? Answer. Why are you answering 264?
Are you telling the score of Rohit Sharma? 264. Rohit Sharma's highest score of 1 day is 264 No See Volume of mixer taken in per stroke Means you have to find out volumetric efficiency What is this? Actual volume upon swept volume Actual volume upon swept volume So volumetric efficiency is 0.88 Into VS How much is VS? 300 I will tell you now VA 300 x 0.88 is 240 300 x 0.8 is 264 Option C will be correct What happened? Answer fast Very good So the answer was 25 Fast fast fast 10 is to 1, 16 is to 1, 35 is to 1, 12.5 is to 1 Fast fast 3215, very good.
3215, 3215, 3215. 10 is to 1, kids, when SI engine is idle. When petrol engine is idle, kids, idle means that your engine is idle. Idle means that your engine is at start but bike is not running.
You are stuck in traffic. 16 is to 1, kids, when your SI engine is running on C2. Okay, when your SI engine is running on part load, at that time you... more than the stichiometric means the requirement of lean mixture 35 is to 1 when your SI engine is running on part load after that 12.5 is to 1 when your SI engine is on full load then you will get 3215 if your SI engine is on full load then how much you need?
CI engine is on full load then how much you need? 18 is to 1 CI engine is on full load then how much you need? 18 is to 1 Why is Mechanical Efficiency not solved? Mr. Janatul Siddiqui, Mechanical Efficiency is not used in this.
Mechanical Efficiency means Brake Power upon Indicated Power In the case of an engine In the case of an IC engine, Mechanical Efficiency is Brake Power upon Indicated Power None of these values are given in this, so how will you solve it? Mechanical Efficiency is used to get Frictional Power Mechanical Efficiency tells Frictional Power Calculate it We are not asked that. We are asked how much actual volume is coming.
The actual volume that is entering upon swept volume that should enter maximum. Its ratio is your volumetric efficiency. So option A will be corrected here. The discharge of hydrocarbon from petrol engine, automobile exhaust is minimum. Minimum.
When the vehicle is. Do you know the answer to this? Fast. No dear, it is not B. It is accelerating.
It is accelerating. Do you know what cruising means? cruising means most economical speed cruising means most economical speed cruising speed is actually economical speed cruising speed in bike is like 40-45 kmph this is the economical speed cruising speed so here option is accelerating when your engine is accelerating means when engine Cruising means not fast speed Cruising means Cruising means Cruising means Economical speed Like you said that you have to drive bike on cruising speed Cruising speed means economical speed Idling means your engine is on Bike is not working Cruising speed means economical speed Accelerating means When bike is accelerating Yes when bike is accelerating How much does bike need 12.5 is to 1 air fuel ratio that means what you need at that time at that time you need rich mixture when you need rich mixture in automobile then combustion will be fast because bike is accelerating bike speed is very high if you increase speed in engine then knocking will be less so when speed increases then fuel combustion will be fast so hydrocarbon will be less chance of being unburnt so emission will be minimum because fuel combustion will be better and minimum you need the exhaust will have minimum hydrocarbon content because combustion will be better which of the following symptoms shows that the combustion is necessarily complete tell me So, the answer will be The mixture is more rich Listen, who asked this? Shubham If the mixture is more rich Listen If the mixture is more rich If the mixture is more rich Then what will happen? If the fuel is too much, like Shubham said that in idling it will be more rich.
So if the fuel is too much, then you don't think that hydrocarbon, fuel is made from hydrocarbon. So if the fuel is too much rich, then the hydrocarbon content will be too much. At that time, the emission of carbon and hydrogen will be too much. The emission of hydrocarbon will be too much.
Okay, let's go. So what will happen here? Which of the following assumption shows that the combustion is necessarily complete. So what is combustion complete?
This is the presence of oxygen in exhaust If your oxygen is more present in exhaust It means your combustion is complete And if carbon monoxide is more present It means your combustion is incomplete Let's come to the next question Yes, if you take a more rich mixer, it will destroy the choke Because the work of choke is to block the air The work of choke is to block the air and keep the fuel more Okay What is the purpose of supercharging an engine? What is the purpose of supercharging an engine? To increase the power output or to reduce the fuel consumption, to reduce the noise of the engine or to improve the cooling of the cylinder. Yes, so why do we supercharge an engine so that our power output increases? We do an engine in a supercharging engine so that your power output increases So option A will be correct here Next question comes Welcome dear welcome Thank you all for your compliments Let's go Detonation in the SI engine becomes severe during Actually, I know.
I went to Gurgaon to watch a movie. I came there at 6 o'clock. I came to know that my class is at 7 o'clock. And when I came suddenly, I came to my room.
My panel, I mean digital board. The wire of the board was cut by a mouse. The digital board was cut by a mouse.
There was no one at home. He thought that he was the king. So the wire of the board was cut by a mouse. So I said I had another wire but it is kept somewhere inside and I can't find it.
I will change it tomorrow and it will work. Detonation in the SI engine becomes severe. When does detonation in the SI engine become severe? Everyone will answer fast. No dear, Shubham I already have that.
It is kept but what to do Detonation in SI engine becomes severe during I am not going to tell the name I am not going to tell the name Detonation in SI engine becomes severe during So in SI engine, when is detonation severe? When the load is more on the engine High load And when the speed of the engine is very low So high load and where is it? What is it?
Where is it? High load and low speed. High load and low speed.
Option D will be correct. Option D will be correct. Okay. Next question.
The way he cut the delete, I felt for the first time that what is shardness? In this material, we just asked a question. You must remember that we just asked a question yesterday.
If one material is hard, what does it mean? That it can cut other materials. So, in their teeth, there is a substance called enamel.
And it is very hard. It is more hard than human teeth. So, the hardness they have, resistance to indentation, is very dangerous. In the SI engine, highest unburnt concentration is observed. During?
During. Highest? unburnt hydrocarbon concentration is observed during, on which? Highest, when will it be reduced?
Highest. Okay, deceleration, not idling. It is deceleration.
If your bike decelerates, if your bike is decelerating, then at that time, what will you get? Highest unburnt hydrocarbon emission will be received. If your bike is decelerating, if your bike is decelerating, that means you are reducing speed suddenly. If you are reducing speed suddenly, then, see, when the speed of the engine was very high then the flame propagation of the air was very fast but when you suddenly reduced the speed then the flame propagation reduced very suddenly you reduced the speed then the flame propagation started to decrease suddenly so it is possible that the combustion is not being properly completed in it at that time, in the time of deceleration, unburnt hydrocarbon is emitted a lot so the option will come let me tell you one thing, in acceleration, we come out the least so what will come out in deceleration? the most okay Option C. Next.
Let's answer this. Come on, man. No problem.
There is a closed balloon which has 10 kg of helium which is receiving 5 kJ per kg of heat. And, guys, this is your 100. Here, the value is 100 kPa. This is 100 kPa. Closed balloon containing 10 kg of helium receives 5 kJ per kg of heat. During this process, the volume of balloon slowly increased by 0.2 m3 at constant pressure of 100 kPa.
The change in internal energy in kJ. So, change in internal energy. How will we find out the first law of thermodynamics process? If we apply, then what is said?
dQ is equal to du plus dw. Applying the first law of thermodynamics equation for process. So, dq is equal to du plus dw. How much dq is left? See, 5 kJ per kg.
And how many kg is there? 10 kg. So, how much will come? 50 kg. 50 kJ.
1 kg helium absorbs 5 kJ heat. So, 10 kg helium, how much will it absorb? 50 kJ. Next. du.
change in internal energy is 100x0.2 which is 20 100x0.2 is PDV which is 100x0.2 which is 20 so here we have 20 and DU is 30 option C is correct we will answer fast, please like the session please like the session B ok let's see we have to apply same in this also if we ask change in internal energy then what we apply is du plus dw here it is said that heat is being rejected heat reject to cooling water heat rejected means minus 75 heat rejected means minus 75 DU is asked and DW is work input work is done on the system means work input work is done on the system it is minus 125 so here DU will be equal to this minus will go here 125 minus 75 that is 50 50 plus means 50 kJ heat gain next dedication dekho, rishadaroon ghar se bhi padhai kar rahe hain kya baat hai yaar, tum jaisa ladke hi jo hota hai na zindagi mein kuch badaa karte hain the piston of vertical piston cylinder device containing a gas has a mass of 60 kg and cross-sectional area 0.04 m2 the entire system is placed in a vacuum chamber if the temperature of the gas is 70 degrees Celsius what is the pressure of the gas inside the cylinder? Which one is kept? First, it is kept in vacuum.
Means there is no atmospheric pressure. It is kept in vacuum. This whole system is kept in vacuum. Means there is no atmospheric pressure. It is vacuum here.
Now, what will be applied here? The pressure of the piston will be applied here. See, there is gas inside. So, where will the pressure of gas be applied?
Up. Pressure of gas will be upward. The pressure of the piston will be what?
It is the weight of the piston upon area of the piston. So, here for equilibrium. the pressure of gas will be equal to the pressure of the piston which is equal to weight of the piston upon area of the piston so weight is mg upon area so here take out m is 60 kg into 9.81 divided by area is 0.04 we will calculate the answer in bar option B will be given you don't want to take dogs to Thailand?
ok ok, very good, very good, you will surely make something in life your name is Rachit right Sharma ji you will make something big in life, confirm I understand gold is also an art in itself, gold is the biggest art 56 watt No, 56 watt will not come This is wrong 36 watt will come How much will come? 36 watt will come So let's see what will come There is a heat engine Which is using lake water See, let's remove its efficiency first Let's remove its efficiency first See, on which it is working There is a heat engine On which it is working There is a heat engine So see, here it is 12 degree 12 degree means 285 Kelvin And this is 2 degree 2 degree means 273 275 kelvin 275 kelvin and it is producing work this is what it is asking you and see, executes 1080 cycle per minute it is delivering 1080 cycle per minute so number of cycle per second number of cycle per second how much will it be 1080 divided by 60 so this will be cut and here will be 18 18 cycle per second 1080 cycle per minute means 18 cycle per second and in one cycle it is consuming 57 joule of heat so in 18 cycle q total total heat absorbed q absorbed it is 57 into 18 57 into 18 so guys here you are having heat supply this is equal to heat supply and efficiency you can calculate from 1 minus p lower upon t higher 1-275 upon 285 efficiency and it is heat supply heat supply is given efficiency is given you can calculate the work done you will get 36 watt next Absolutely. Very good. Very good.
Children, we say that a tin is a shade. Do you know tin? Oil container. Container of oil. Tin is your family, your relatives, your family.
Basically, it is like a tin. You will feel that it makes a lot of noise. You will feel that it makes a lot of noise.
But actually, if you ask, it gives you the same shade. you will get the same effect. Rest, when you will face difficulties, then all your high-hello friends, who come out by saying hi, bye, all these will be removed.
They will only come in trouble. And you should never feel it. A building in cold climate is to be heated by a Carnot heat pump. The minimum outside temperature is minus 23 if the building is to be kept at 27 degrees Celsius and the heat requirement is 30 kilowatt. What is the minimum power requirement for the heat pump?
so first we will find the COP of the heat pump first understand what we are asking this is the heat pump we have to give it work heat pump will give Q2 temperature from T lower and Q1 from T higher see how much is T higher T higher is 300 Kelvin T lower is 250 Kelvin which is minus 23 Kelvin Let's find out its COP first The heat requirement is 30 KW What is the minimum power requirement? This is the minimum power requirement or minimum work requirement How to find out the COP and the heat pump? The COP and the heat pump will be T lower which is 250 upon T higher 300 divided by 300 minus 250 300 by 50 will be 6 see here COP is desired effect Q1 upon work supply Q1 Q1 Q1 is 30 30 by COP is 6 will be 5kW option will be de-corrected the compression ratio 25 for an air standard diesel cycle the total heat of 800 kilojoule per kg is supplied during the reversible constant pressure heat addition process while 400 kilojoule per kg of heat was rejected heat was rejected during reversible constant volume process the efficiency of the cycle is d Let's see. Okay, so what will be the efficiency cycle? It is 1 minus heat rejected upon heat supply.
1 minus, heat rejected is 400. Heat supply is 800. How much will be 1 minus? 0.5. How much will be? 50%. Option D. Next.
Efficiency of ternote cycle can be increased most effectively by The efficiency of Carnot cycle can be increased most effectively by? Tell me quickly, answer the next block fast, everyone. And guys, those kids who are new here, like those kids who are watching for the first time here, then understand that our daily Bark class is also there.
Skybendry training, which is our 7-8 daily Monday to Friday. This class is RRB and SSTJQ. After that, our class is 8-9 Bark daily.
And our master class is on the test book app, which is free for you. That is 9.15 am and 1.30 pm. So, efficiency of Carnot cycle is 1-T lower upon T higher. Better to decrease T lower. Better to decrease T lower.
Increasing the... No, no, no. How to increase it, sir?
Better to decrease T lower. That means decreasing the lowest temperature. Decreasing the lowest temperature. Next.
DBC ki class jo hai, Manish ji. It is difficult to understand separately but you can cover it in this class. If you will ask then I will ask you questions of DVC level in this class.
But it is difficult to understand separately. Carnot cycle is operating at temperature limit 1800 Kelvin and 1000 Kelvin. What will be the lowest heat rejection per kilowatt net output of the engine? This is 1800 Kelvin and this is 1000 Kelvin.
This is car not engine, it is working. This is heat engine, car not engine. So, what will be the option? Yes, the option is actually 1.25. So, it is here Q2 and here it is Q1.
Now guys, it is asking about what will be the lowest heat rejection per kilowatt net output of the engine if the car not cycle operates between the temperature of 1800 kelvin and 1000 kelvin what will be the lowest heat rejection per kilowatt net output of the engine ok kids what will be the lowest heat rejection per kilowatt net output of the engine he is taking from here Q1 and Q2 sorry this diagram is a little bit wrong because this is car not engine head here I made it refrigerator engine is 1800 divided by Q1 Here is the engine, what will it do? It will work and will reject Q2 heat. How much is it here?
1000. Now, you ask, what is the lowest heat rejection? What is the lowest heat rejection? Q2 per kilowatt means W.
Q2 by W. What is Q2 by W? It is the COP of refrigerator. What is the Q2 by W?
It is the COP of refrigerator. Today, what are you asking? What will be the lowest heat rejection? Heat rejection means Q2 per kilowatt. Net out.
output means W Q2 by W what is this? COP of refrigerator what is COP of refrigerator? it is Q2 by W and how will you get the COP of refrigerator?
first COP of heat pump how much will be 1 upon efficiency of engine so how much will be the efficiency of engine? what is the efficiency of engine? the efficiency of engine will be 1 minus T lower upon T 1000 divided by 1800 you have to calculate like this so 1 minus 10 by 18 This will be its efficiency i.e. 18-10 8 by 18 This will be its efficiency So what will be the COP of the heat pump dear?
18 by 8 18 by 8 is the COP of heat pump So what is the COP of refrigerator? 18 by 8 minus 1 So we will calculate 18 by 8 minus 1 i.e. 18 by 8 How much will be 10 by 8? 10 by 8 will be 1.25 Option C will be correct What will be? C will be correct ok, next question Shubham, we could have applied it because if you see this side this is actually heat rejection ratio but if you tell like this, the kids won't understand how it came to 1000 by 800 tell me Which of the following statement is true about an engine having an efficiency of 60% working under a temperature of 1000 Kelvin and 540 Kelvin? Efficiency is asked.
Which of the following statement is true about an engine having an efficiency of 60%? How much is the efficiency of an engine? 60%. In which case, the work is done?
The temperature limit is 1000 and 540. In which case, how much is the efficiency of an engine? In between this, what is the maximum efficiency between this temperature limit? So, 1 minus 540 divided by 1000. So, it is equal to 0.46. The maximum efficiency between this temperature limit could be 46%. But here the engine is having 60% efficiency means it is not actual, it is hypothetical.
Next. While working between temperatures of 150 Kelvin and 300 Kelvin, the entropy change experienced by the Carnot engine during the heat addition is 1 kJ per Kelvin. The work produced... in kilojoule by the engineers answer fast 150. let's do it in rapid fire because we are having so many questions Now we will go to properties of steam and will cover many questions of it.
So guys, see here, what is the temperature limit? 300 and how much is this? 150. Here an engine is working, taking heat Q1 and W and how much is Q2? Now I am asking you, the entropy change experienced by the Carnot engine during heat addition.
During heat addition, entropy change, what will happen? Q1 upon T1. Q1 upon T2.
T1 is 300 is equal to entropy change is 1 entropy change is 1 during heat addition so DS is equal to 1 Q1 upon T1 T1 is 300 so here Q1 you will get 300 Q1 will be 300 today the session is only for thermal engineering as you have seen in the thumbnail so it is only for thermal engineering session so Q1 is 300 Q1 is 300 how much is the efficiency of engine 1 minus 150 divided by 300. How much? 50%. 50% is efficiency. Heat supply is 300. That means it will take 300. And efficiency is 50%.
300 will take and 50% will be converted into work. So how much will heat reject? 50%.
How much will work produce? 50%. 50% means whose? 300's 50%.
How much will be? 150. Next. Guys, we will answer fast in rapid fire.
Fast. Answer adiabatically fast. Fast.
pure substance is below the triple point temperature the solid on being heated will only everyone answer the question fast guys we are going in the properties of pure substance section and there will be solved solving good questions okay santosh it is the marathon today now from seven to nine it is continuously two hours marathon So these questions are absolutely very important for the bark deer. This is very very important for the bark. So what will happen? Have its temperature increased.
That means where are you working? There is a P-T diagram. There is a pressure and temperature diagram. And this is your triple point.
What is your triple point? So this is your triple point. If a pure substance is below the triple point temperature. So this is your triple point temperature.
Pure substance is below the triple point temperature. So if a pure substance is below, it is here. the pure substance is below the triple point temperature means this is the state of the pure substance now you are going to heat this when you will heat this what will happen only temperature will increase only temperature will increase so option d will be correct next at lower temperature and pressure the latent heat of vaporization of a refrigerant answer answer At lower temperature and pressure, the latent heat of vaporization of a refrigerant will increase. At lower temperature and pressure, latent heat will be more.
With increase in pressure, as the pressure increases, latent heat will decrease. Next. During change of phase from ice to water, the specific volume. Answer guys fast. Hurry up everyone.
During change of phase from ice to water, the specific volume. What will happen? See.
The density of ice is minimum. And specific volume is maximum. Water is at 4 degrees Celsius.
Water is there and its density will be maximum and specific volume will be minimum. So, maximum to minimum means decrease. Next.
Gases at low pressure behaves. We will answer fast. Everyone, fast.
Ideal, real. Ideal liquid, real liquid. Ideal liquid.
Very nice. Gases at low pressure behaves as an ideal liquid. Very nice. Who answered this? ideal gas ki tarah behave karegi.
Aur wo bhi approximately, wo bhi approximately ideal gas ki tarah behave karegi. Next question. An ideal gas as compared to a real gas at very high pressure occupies?
Answer guys, fast. an ideal gas as compared to real gas at very high pressure occupies very less volume very less volume because there is no intermolecular force Because there is no intermolecular force in ideal gas. Okay. Next.
The shell of Cochrane boiler is made hemispherical. Why is the shell of Cochrane boiler made hemispherical? Tell me.
Yes, to give maximum... See, the shell of Cochrane boiler is made hemispherical because we make such a boiler shell. Why do we make it hemispherical?
Why do we make a hemispherical shell of boiler? So that it can give maximum space and strength, increase turbulence, withstand the pressure of steam inside the boiler. It can withstand more pressure, give maximum space and strength.
What do we do because of this? We make boiler shells hemispherical. Next pattern.
Do you know the answer? It is real. A boiler is being produced.
Look at the mass of steam. Mass of steam. Mass flow rate of steam. How much is it? 1000 kg per hour.
With rise in enthalpy, i.e. delta H, means Hg minus Hf. How much is given to you? 2500 kJ per kg.
And the calorific value of coal is used. What is the calorific value of coal? 30,000 kJ per kg.
How much is consumption? Consumption means mass flow rate of the coal. Mass flow rate of coal. How much is left?
100 kg. What is the efficiency of boiler? Efficiency of boiler is steam production capacity divided by heat supply Steam production capacity is mass flow rate of steam into Hg minus Hf upon mass flow rate of coal into calorific value Means net effect upon heat supply so mass flow rate will be 1000 into Hg minus Hf 2500 divided by mass flow rate of coal 100 into 30000 we will solve and multiply by 100 and to convert it into percent your answer will be B next method option B which of the following is not a factor for selecting a type of boiler for a particular application For any particular application, there is no such factor that we keep in mind while selecting the boiler. Yes.
So, fuel and water are available. Absolutely. And steam generation rate is absolutely available.
Floor area is absolutely available. Sameer and I have said C. Sameer, friend, it will not be like this. C will not be there. because if you have floor area available if you want to put a boiler in a plant and your plant is 1 BHK your plant is in 1 BHK area 1 BHK means 1 bedroom, 1 hall and 1 kitchen can be made easily so you can put boiler you can put power plant boiler if the whole plant is in 1 BHK means in 70-75 Gaj you can put boiler in power plant you can't put it right?
So floor area is available. This is a very important factor. If you want to install a power plant on this, then the floor area should be more.
So what is the climate of the reason? There is no point in this. Whether it is hot, cold, rain or fire, if you want to install a power plant, then you have to install it. Let's go.
Next. With whom do we produce natural drought? not of same temperature dear of more than that temperature the artificial the china has developed an artificial sun having even more temperature than the original one but i think this is just a rumor some alleged facts these are these are not facts these are some rumors Natural drought is produced by the use of chimney. We produce natural drought with chimneys. We can produce artificial drought with fans or steam jets.
Furnace is situated outside the boiler shell in a case of... Tell me the answer. Everyone will answer fast.
Furnace is situated outside the boiler shell. Very good. So, in the case of water tube boiler, the furnace is outside. Option B. If someone sees this, what will you say?
This is natural circulation. Natural circulation. Water tube boiler. Next.
Which boiler has relatively large storage of steam and water? They can make anything. Indian kids, how will you make it?
Indian kids are focusing on Bhandara. Indian kids are focusing on Bhandara. How will you make it? Which boiler has a relatively large storage of steam and water?
So, which one has, kids? In the Lankashire boiler. Whose steam generation capacity is very high. Approx 9000 kg per hour.
9000 kg per hour. Okay. Next.
Yes, we are looking for poori sabzi. In our Lankashar boiler, the heat is transferred to the water by... Guys, we have included a lot of questions here.
Like thermodynamics, IC and REC power plant. A lot of questions are included here. So, you quickly answer this.
In our Lankashar boiler, the heat is transferred to the water by... Guys, are you copying someone or answering with your mind? I saw Shubham wrote D. So, 2-3 people wrote D. How will D be?
Dilip, I agree that your name is D. It doesn't mean that your name is the answer. No, sir. Change it.
What will it be? Flu tubes immersed in water. In Langashar boiler, flu tubes are immersed in water. So, there are flu gases in the tubes.
And there is water next to it. Water is outside and there is fire in the tubes. It means there are flu gases.
So, the tube is immersed in water. And because of that, heat... Tell me one thing, how is the heat transfer going in the fire tube boiler? See this is your shell, so this water is out here and these are the flue tubes, they are in it. I hope my pen will come off, if it comes off, it will be a big loss.
If it is in the flue tubes from here, see this is the test book company's boiler, let me show you. This is the test book company's boiler, we have just made it new. Let's put the flue tube in it, so the flue tube is very hot, it is getting flue gases in it. So it is hot and the water is all around, so what will it do? It will heat the water.
water will heat it up and the fun of drinking hot water is different the fun of drinking hot water is different so today we will learn about flue tubes immersed in water next pattern 83 will not happen. India had won the world cup. I agree India won the world cup first.
In 83. But this doesn't mean that 83 will be the answer. 90 will be the answer. How much will be the answer?
90 will be the answer. Boiler means 9 kg of steam. What is the efficiency of boiler?
What is the efficiency of boiler? Now we have taken out the last question. Mass flow rate of steam into delta H upon upon MF mass flow rate of coal into CV This is what we got How much will come? See Steam's mass flow rate is 9 How much is 9?
Into See The enthalpy of feed water are 300 And steam's is 3000 So you will write 3000 minus 300 Divided by Mass flow rate of coal 1 kg per 9 kg of steam per kg of coal burnt How much is coal? 1 kg Into The calorific value of coal is 27 MJ So 27 MJ means 27000 27 mega joule means 27000 kilo joule Calculate and your answer will be 90% See it is very easy you can do like this 9 x 27000 27000 will be 0 0 27000 will be 10 and 10 will be 0.9 multiply it by 100 and it will be 90% let's move on to the next question very good have you started a class in the market? start a class in the market don't start it with a glass ok kid, start a class in the market don't start it with a glass at this time, will you drink more sugarcane juice? or cold? It will cause a lot of damage in rainy season.
As per IBR regulation, the boiler should be fitted with how many safety valves should be in the boiler? Two safety valves. Two safety valves should be there.
Okay? Yes. Because if one fails, the other one should work. Next, man.
The enthalpy of feed water and steam at exit of a boiler are 73 and 2800 kJ per kg respectively. The steam output is this much. The equivalent evaporation you have to get.
I don't think it's A. I don't think it's A. I think it must be B.
I think. What is equivalent evaporation? Equivalent evaporation is mass flow rate of steam into Hg minus Hf divided by latent heat.
Okay. So, how much is the mass fluid of steam? 1128.5 into Hg is 2800 minus Hf is 73. And Lh, latent heat of vaporization is what? Lh is 2257 kJ per kg. Latent heat of vaporization of water is 2257. We will solve it and your answer will be 1363. 1363 will come.
Let me calculate once. You will confuse everyone. Someone will tell me what is the correct answer.
Please. Here, your answer will be 2800 minus 73 into 1128.5 divided by 2257. 1363.5. Option B will be correct.
Next. Tell me. There is a boiler plant in which 600 kg per hour of steam is supplied at 10 bar and 250 degree Celsius with enthalpy content 2942.6 kJ per kg from the feed water at temperature 37. The liquid enthalpy is given at this time it uses 800 kJ per hour of coal having calorific value which is 30000 kJ per kg. Efficiency of boiler is again same question. So let's see how much answer will come.
Guys tell me the answer. How much answer will come? Again, we will see how to get out mass flow rate of steam into Hg minus Hf divided by mass flow rate of coal into calorific value.
So, the mass flow rate of steam is 6000 into Hg. Hg is 2942.6 minus Hf is 154.9 divided by mass flow rate 800. into calorific value 30,000. How much is the answer? What is the answer here? Answer, answer, answer fast.
How much is it? Is C coming? C is coming.
Okay. This is coming, option C. Let's go to the next method.
Maximum working pressure in a Lankashire boiler. How much maximum working pressure will be in a Lankashire boiler? Tell me.
Let's do it in rapid fire. Okay, let's do it fast. How much will be the maximum pressure of the boiler?
16 bar. How much is it? 16 bar. Next question. How much is the operating pressure range in a fire tube boiler?
We will answer this quickly and fast. In a fire tube boiler, D is 10 to 20. 10 to 20, 10 to 20, no no no. It is 16 to 20. 16 to 20, what will be 16 to 20?
The maximum operating pressure range of a fire tube boiler is not 20, it is not 18, but it has a locomotive which has 25. Locomotive boiler is a little exceptional. which has 25, rest all have around 16-18 which of the following doesn't come under the forced circulation type of boiler which of these is not forced circulation ok, yes maximum head here, that maximum is 25 25 is maximum, rest 16-18 is maximum and like cornish boiler works on 10-12 bar and cocoran boiler also works on 12-13 bar so 16-18 bar is below maximum 16-18 is maximum but locomotive's maximum goes upto 25 so this will be lankashire rest will be willox, benson and lomond so i will put all the pressure on here lankashire 16 bar willox boiler 84 bar benson boiler approx 230-240 bar This is approximately 86 bar from 84 Lamont boiler is 170 to 175 bar Next The most appropriate example of dash boiler is Cornish boiler No, no, it's 135, dear. Ah, 134, 135. Yes, you can say 134, 135. There is no exact value.
In any book, you will not find any exact value. Like if someone says that the pressure of the boiler is 84 bar, then wrong. 84, 85, 86. So, this is the approximate answer.
What is a fire tube boiler? Cornish boiler, kids, what is a fire tube boiler? Next. Tell the answer, fast. yes, it is no lord B will not come B will not come see child, what do you ask power developed by turbine how much is the work of turbine Power developed by turbine is 1206 kW and the power of the pump is 6 kW So if I talk about the net power Net power is 1206 minus 6 and this is equal to inner cycle because this is Rankine cycle in a cycle according to first law of thermodynamics net heat transfer is equal to network transfer so what is net power or network transfer 12.6 minus 6 it is equal to net heat transfer what is net heat transfer it is equal to mass flow rate into hg minus hf this is net heat transfer okay now here the heat or you can say this is a heat supply minus heat rejection it is equal to m dot heat supply minus heat rejection so m dot you have to calculate the heat supply see the heat supply is 3500 and heat rejection is 2900 so this is equal to 1206 minus 6 means 1206 it is equal to m dot into 3500 minus 2900 is 600 m dot will be 2 kg per second next What is the typical composition of the casting employed in the oil-fired boiler?
Very good. If there is an oil-fired boiler, means if there is an oil-fired boiler, like you know that there is a coal-fired boiler, there is an oil-fired boiler, So we use different fuels in different boilers. If there is an oil-fired boiler, then when we cast that boiler, when we are making that boiler, then which materials are used in it? 50% nickel and 50% chromium. Because to avoid this from the corrosion and all, we use this 50% nickel and 50% chromium.
Next. Okay, what is the range of length of Cornish boiler? What is the range of Cornish boiler?
15 to 50 meters? Brother, who is he? How much will it be? 4 to 8 meters.
How much will it be? 4 to 8 meters. Okay, so what is the range of Cornish boiler?
How much is it? 4 to 8 meters. Next.
And the dia of this is, dia, What is the range of the dia? This is 1 to 2 meter between Generally 1.2 or 1.2 to 1.6 something meter Next Fusible plug, from which it is made in boiler Fusible plug. Who has it in boiler? Answer guys. Fast.
We will do it fast. It is 8.30 pm. And we have to do a lot of questions. At least 30 questions we have to cover in 30 minutes. At least we have to cover 30 questions in 30 minutes.
Okay. So let's go fast. Who has it in brass?
So fusible plug. Either you make it in brass. Brass.
Whose alloy is it? Copper and zinc. Either you make it in gun metal. Who will you make it in? Gun metal.
What is gun metal? Copper, zinc and tin. Okay. Copper 88. zinc 2 and tin 10% this is its ratio what should all this be made of? made of a low melting point alloy what does a fuse bar plug do?
it saves the boiler from overheating and where is it attached? on the boiler crown next okay operating pressure for once through boiler once through boiler means like Benson super critical boiler operating pressure 230 240 bar what is critical pressure critical pressure it is 221 bar approximately 221 bar approximately next Think about it, if you have a gun, you are standing here with a gun This is a new gun, this is a Mauser. This is a Mauser.
Hitler used to use this in Germany. Suppose you have a gun and the melting point of this gun is very low. The melting point of this gun is very low. You have a gun and its melting point is low. You fired a bullet.
When you fired a bullet, heat was generated here. And the barrel of your gun fell under the melt. The bullet did not reach the front, the barrel of the gun fell under the melt.
In the PV diagram of pure substance, which of the following reason... Oh, oh, oh, did I leave a question? Yes.
Define pure substance. Define pure substance. No, no, I left this question. Okay, bro.
Define pure substance. Define pure substance. Option D. B. Substance which is available in purest form in nature.
Okay. Okay. The purest form in nature is available, that is pure substance.
Okay. D. Substance with fixed chemical composition throughout the mixture. Throughout the mixture.
And what else? Fixed chemical composition and chemical aggregation as well. Chemical aggregation as well. So, any substance of any component is of the same chemical composition throughout the mixture. And if the chemical aggregation or bonding is the same, then such substance is called pure substance.
Like your water-air. Water-air. Not water-air. Water and air.
Like water and air. Next. In a pure substance, there is no reason for a PV diagram. So, you all answered it earlier. That there is no reason for a super cooled vapor region.
How can vapor be super cooled? If vapor is super cooled, then where is the vapor? It is liquid. If the vapor is super cooled, then it will not remain in the vapor state.
Definitely, it will be in liquid state. Therefore, it is called sub-cooled. At the absolute temperature, scale needs only one fixed point, which is which is yes triple point of the water so how to define 1 Kelvin?
1 upon 273.16 of triple point of water how to define triple point of water? next how much is the triple point? so 0.01 degree Celsius means 273.16 Kelvin choose the correct answer Critical point involves equilibrium of solid and vapor phase.
Critical point involves equilibrium of solid and liquid phase. Critical point involves equilibrium of solid and liquid and vapor phase. Yes, obviously.
Triple point involves. Very good. Option C will be corrected. Very good. Very nice.
Deepak is saying that answer A will be corrected. Very good. Very nice.
Your father is watching our lecture and he is also a teacher in college. So, if your father is watching the lecture, first of all, greetings to your father. And tell him to bless you.
That we should also move forward and you should always move forward in life. You should always move forward with your family. And do something in life that your father will be proud of you. Okay, friends?
The day you gave your father and mother the biggest gift of your selection, you cannot give them a bigger gift in life. You cannot give them a gift of your selection. And you cannot ever guess this happiness. ok so let's go this is our wish to you all ok so let's go so see what will come here critical point involves equilibrium of solid, liquid and vapor phases so choose the correct answer triple point involves equilibrium of solid, liquid and vapor phase so what is your triple point so you take a glass vessel and take water in it and start reducing the temperature of this water what is the temperature of room dear it is about 27 degree celsius 27 degree Celsius is room temperature decrease temperature to 0.01 degree Celsius and decrease pressure to 0.611 kilopascal now pressure is 1,1325 pascal decrease pressure to 0.611 kilopascal and when you reach 0.01 degree Celsius temperature you will see triple point where you will see three phases of water you will see practically that in the glass vessel you can see ice, vapor and liquid this is called triple point now if you talk about critical point how critical it will be sir Somgoji critical will not be B critical point is that point where there is a liquid and vapor interface Critical point is the point where the liquid and vapor interface is.
That is called critical point. In all these options, the interface of liquid and vapor is not written anywhere. If you read carefully, then option D will be done. Okay. Let's move to the next.
Mr. Reynolds, you have... I have tied it up. Papa is also watching the lecture.
Oh, Lord. There is liquid and vapour, right? So, I am also saying the same. I am also saying liquid and vapour.
I am also saying liquid and vapour. Sir. I am also saying liquid and vapour.
Hey, listen. What is the name of this? Somghosh. I am also saying that where is the liquid vapor in this option? Critical point is the point where there is equilibrium of liquid and vapor.
But in this option, solid, liquid and vapor are not given. This is not the option. That is why there is a triple point here, on which solid, liquid and vapor co-exist.
Understood? Yes. Joule-Thor-Mission coefficient for an ideal gas. So, what is the Joule-Thor-Mission coefficient of an ideal gas? Okay.
What is the Joule-Thor-Mission coefficient of an ideal gas? Tell me fast. Is it 1, 0, minus 5 or 10? So, tell me what is the Joule-Thor-Mission coefficient? Joule-Thor-Mission coefficient tells us that any ideal gas, if it...
is passing through a throttling process means a very small opening if you have a device with a very small opening and an ideal gas like air is passing through a very small opening then what is that? it is a throttling process so when it is passing through a throttling process then how is its pressure and temperature varying? so I told you that the method to remember the Joule-Thomson coefficient is you will write Thomson's plot so this is called the Joule-Thomson's plot or Thomson's plot Thomson upon plot T by P so Remember, what is the method of remembering? Del T over del P, whose constant enthalpy line? So, for ideal gas, what happens?
Zero happens. For ideal gas, what is the Zoolth option coefficient? Zero. Why?
Because enthalpy of ideal gas is constant. And for ideal gas, the enthalpy is the function of temperature. If enthalpy is constant, then temperature is also constant. If temperature is constant, then DT is equal to zero. If DT is equal to zero, then mu is equal to zero.
If DT is zero, then mu will be zero. It will be zero. Option B will be done. Next part comes. And if any child's respected father is watching this lecture right now, I would like to request him to drink tea.
It's 8.30 pm right now. Let the child study and you can drink tea and water. Uncle, auntie, if anyone is watching, I request them to let the child study and you can drink tea and water. Walk around the balcony and drink tea and water. This is an invitation from a child.
So, I guess having negative Joule Thomson coefficient. Mu less than zero Ben throttled will Tell me No because I am not saying this for myself I am saying this for you guys Because if father Or mother If they sit with you And take a lecture And say brother You will see the chance Then you will not be able to answer You will get in pressure I am saying this because Kids cannot calculate Kids'mind is on you That papa is watching So kids'mind Your kids are Albert Einstein these kids in the comment box are all Albert Einstein they are their own form so their brain gets better so you guys can stand in the balcony and have tea a gas having negative Joule-Thompson coefficient when throttled will ok so if Joule-Thompson coefficient is negative If Joule-Thomson coefficient is negative, then what will happen? Del T over del P. If this child is negative, then what I have told you is that in Joule-Thomson coefficient, the pressure which is there during throttling always decreases. So, the del P will always be negative.
The pressure which will be there in the throttling process, that always decreases. So, when the pressure decreases, this will always be negative. So, now in denominator, you have to write negative always.
So in denominator you should write negative always. Now this mu is negative. Now if mu is negative in denominator then it is negative.
This means numerator should be positive. Numerator positive means tt must be positive. Means t2 minus t1 must be greater than 0. Means t2 is greater than t1. Means we are in heating region.
Temperature is increasing. Joule Thomson coefficient negative means temperature is increasing. Garmi badh rahi hai. Becomes warmer.
Next. No, no. Give me some sunshine. No. Kids must be singing this.
Give me some free time. Don't give me the pain. give me some free time don't give me the pain please take your tea and go in balcony because i want to calculate once again please take the tea and go in balcony because i want to calculate once again i eyes when heated directly sublimate into water vapor without going through liquid phase when ice when heated directly sublimates into water vapor without going liquid phase see whose question is this critical point so brother this is your fusion curve and this is your vaporization curve and this is your sublimation curve so this is pt diagram this is solid here is liquid and here is gas now see have you ever lit a fire at home if you have ever done aarti at home Ashwani ji my daily class Ashwani ji she goes yeah My class runs daily from 7 to 9 pm.
Daily class. My daily live class runs from 7 to 9 pm. Why? Why?
Why? Why? Why? Why are you asking me this?
Why did you come to the teaching line? Are you insulting me or praising me? Was this an insult or praise?
Tushar Kapoor ji once came to KBC and was sitting in front of Bachchan sir. So Bachchan sir asked in a very loud voice, Tushar ji, you are so good at reading. So tell me how did you come to this line of acting? So Tushar Kapoor ji could not understand whether Bachchan is praising or insulting. He could not understand whether he is praising or insulting.
If you have ever burnt a kapoor at home, if you have ever done aarti, then you must have seen that when you burn a kapoor, when you burn it, then it directly... it will be converted into vapor if you burn solid solid will be converted into vapor and not into liquid phase solid will be converted into liquid phase that is called sublimation in hindi it is called urdhopatan if any solid is converted into vapor without undergoing any liquid phase when will this happen when you will keep it under critical pressure see critical pressure is 611 pascal if you are under this it will be converted into vapor So, pressure is lower than critical pressure. Option B will be correct.
Next. Wood also. Wood also. Critical pressure of steam.
How much will be the critical pressure of steam? How much is the steam's revolutionary pressure? 221 times Let's come to the next question Don't waste time Let's come to the next question Only throttling calorimeter is used for measuring Oh oh oh Only throttling calorimeter is used for measuring Only throttling calorimeter can do this work Only 56 answers please 56 answers please Sir, you will take it till 56 Till now 56?
Till now 56? You will take it till 56 sir? only throttling calorimeter is used for see kids throttling calorimeter which is throttling calorimeter it helps to measure the dryness fraction if you want to measure the lower dryness fraction then you are having separating calorimeter but this throttling calorimeter is used to measure the very high dryness fraction up to 98% 98% next Amount of heat required to convert one unit of substance from its solid phase to its liquid phase without any change in temperature is called solid to liquid solid to liquid is to be converted but temperature should not change Mr. Reynold, is the fog still on? is Reynold number 0? The amount of heat required to convert one unit of substance from its solid to liquid phase.
You want to go from solid to liquid. You want the temperature not to increase. You want to go from solid to liquid.
Like ice. Now you put one ton of ice in the room. Heat that ice.
The ice will melt and become water. So the amount of ice will cool down. That is called one ton. You put one ton of AC. So what does one ton of AC mean?
That one ton of ice is kept in the room. One ton means 907 kg. So you put one ton of AC in the room.
Don't take 1000 kg because 907 kg is 1 ton. US ton, American ton, Indian ton, empirical ton, British ton, American ton. You have kept 1 ton of ice in the room. That ice melted completely in 24 hours. It melted and became water.
The room is cooled down. That is called 1 ton AC's power. That is its capacity.
That is its capacity. So, what is it called? What heat does it take?
This is called latent heat of fusion. Or latent heat of vaporization. Change in enthalpy. Change in entropy. What is it called?
This is called. This is called Latin treat of fusion. Next question.
Let's go. Leave now. Balcony. Let's go. Why weren't you able to tell me till now?
Why weren't you able to tell me till now? From so long, my breath is blowing inside. I am suffocating. It feels like, if God hadn't made this heart, heart means search tank, then when would my veins have burst from the water hammer?
My veins are also getting so much pressure, so much pressure that the water hammer is running inside. This is heart, search tank, which saved me. Why couldn't I tell earlier?
Which of the following statement is correct? Which of these statements is true? So, see, this statement is, pressure and temperature are independent during the phase change.
Wrong. Isothermal line is also a constant pressure line in wet region. I told you that I had just asked this question.
Isothermal line in wet region is the same as isothermal line on constant pressure line. In wet region, isothermal line is equal to constant pressure line. Now you will say, why not? Pressure and temperature are independent during phase change.
No. Pressure and temperature are dependent on each other during phase change. If pressure increases, then temperature will also increase.
If pressure decreases, then temperature will also decrease. Next. Questions are like guys, who asked this? Kattar Hinduji.
There are approximately 20 questions left. But there is no time. So, we will end after 70 questions. Okay.
Guys, just 70 questions. After that, we are going to end the session. Dash line on Mollier chart represents dash process.
Dash line, dash process. Dash line, dash process. Very good. So, Mollier chart, guys, what is HS diagram? What is HS diagram?
S. So, if you draw a vertical line, dash line on dash chart represents dash process. That means, if you draw a vertical line, it will be constant entropy, i.e. isentropic.
If you draw a horizontal line, it will be isentropic. Horizontal line isentropic, vertical line isentropic. Option P. Next, superheated vapor behaves approximately as an ideal gas. Let's go to the next question. Leave it.
For all substance, the slope of sublimation and vaporization curve are either... Are either... Mr. Reynald, I will definitely do you a favor. Because today you stopped my breath, so I will do you a favor.
Like today, if your father is watching you, then you said, say something for your father. If ever in your life, someone else is watching you, if you will say for him, then I will say for him too. This is my promise. Look, I don't do partiality.
We are the family of the family. I always say that we are the family of the family. We consider the earth as a whole family.
So if you will tell someone else, I will tell him too. Don't worry. Okay, sir. Let's go.
I always say that this is yours, this is mine. Those who say this, they are small-hearted. Those who are big-hearted, for them, the whole earth is their family.
As it is written in your Shastra, that So we are people of that theory. What is written here? Positive.
What will always happen? Positive. That will be positive.
Okay, I will speak for you, then I will speak well. Okay, what will come here? What did you ask? Sublimation or...
the slope of the vaporization curve is always positive. Guys, always remember, the slope of the sublimation curve and the vaporization curve is always positive. The slope of the melting curve is also positive.
The slope of the melting curve is also positive. The slope of the fusion curve is also positive for most substances. But for water, cast iron, the slope of the melting curve is negative.
although the slope of the melting curve for most of the substance is positive but the slope of the fusion curve or melting curve for water and cast iron it is negative because because these two substance your water or cast iron reverse behavior they expand on freezing and contract on melting next Temperature remains constant, then enthalpy. Reynolds is not answering. Reynolds knows that if I answer and if papa comes by mistake, then he will make me turbulent like this.
He will make me turbulent like this. He will increase Reynolds number like this, that my flow will be so turbulent that I don't know what to say. If the temperature remains constant, then enthalpy. If the temperature is constant, then enthalpy. Tell me fast.
No, that's fine. But see, if you have ever been given such a question, listen very carefully, if you have ever been given such a question, so if nothing is given, then assume ideal gas. Always assume for ideal case. Always assume for ideal case.
So if the temperature remains constant, then enthalpy is unaffected by change in pressure or volume. If the temperature remains constant, then the enthalpy remains unchanged. with the variation in pressure or volume because always assume the ideal case because nothing is given so we are not sure which case is given when we don't know which case is given then we will take the ideal case no so option e will be correct next let's go guys and this is going to be the last question question number uh 71 this is going to be the last question ok I know that you will get the option that don't go near TV so guys what should be this delT over delV delP over delS ok this S here and V here this is negative if we reverse this then what will be delV over delT is equal to delS over delP this P here and this T here this should also be negative here it is not negative so this is wrong this is incorrect ok guys Thank you all for coming to the class. We will end the session here.
Thank you all for coming to the class. Thank you all for coming to the class. And those who want to take any course from Testbook Super Coaching, we are giving you a very big discount testbook by tonight.
And by tonight, you are getting this discount. If you take it before tonight, Testbook or Super Coaching course of AEJ Mechanical Yes, definitely like I said I was a little ahead of you Okay, Mr. Bhabhiduri Okay Yes, absolutely Ramesh I was thinking this from the beginning I was thinking this from the beginning And you reminded me So my thinking is going to be a little stronger Okay, let's go So if you want to take AJ Mechanical's course, you are getting a discount of 95% Approximately 90% discount, 33% extra validity You will get a course of Rs. 11,000 in 2989 The code you have to use is RMISHRA So remember that the offer is only till tonight The offer will end after tonight The offer will end after 7th May 12th In which you are getting preparation flight That is, flight of success You will get flight of confidence Your confidence is being given by Testbook Yes, we will do more production, don't worry Ok dear, and guys if you want to take the bar category 1 and 2 course Then you are getting the course of 7000 in 1819 You are getting the validity of 6 plus 2 months Also, you will not get this offer after 12 pm So, you are getting the validity of 33% You have to use the same code, that is RMISHRA Ok dear, and if you want to take the course of category 2 Then you are getting the discount of 90% here You are getting the course of 6000 for 1560 8 months validity and you have to use same code so today is last day 7th May after this offer will end before this offer ends, all of you get ready lets end our question here if any of you want to see if you want to search link of this course see my video is running see my video is running or is First of all, you have to like this video. I will zoom in a little bit. You can see my telegram link below this video. You will get the link of every teacher's telegram.
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And here you will get this course at a very low rate. AGE Mechanical's full course 10999 you are getting 3219 but you don't have to pay this much you have to click on purchase now you have to enter your phone number here enter your phone number here and apply this code my code is armishra after this you will get this code thank you so much guys and i will inform you in my telegram group that tomorrow our class will be at 9.15 am obviously will it be at 1.30 or not, we will inform you tomorrow wait for a second guys, I will tell you if tomorrow is our class or not just give me one second I will tell you, yes okay guys tomorrow we are having a class at 9.15 and 1.30 so tomorrow we have a class at 9.15 and 1.30 you all must come and we will do classes together thank you so much guys, have a good day, take care, bye bye and love you all bye bye