Lecture Notes: Centrifugal Pumps and Ventilation

Introduction

• Discussion on centrifugal pumps and ventilation systems.
• Importance of understanding formulas and efficiency in these systems.

Centrifugal Pump

Key Concepts

• Centrifugal Pump (CFAL Pump): Uses force, particularly tangential force.
• Efficiency and Power: Efficiency is calculated as output power divided by input power, often in percentage form.
• Monometric Efficiency: Theoretical efficiency often used in calculations.
• Head Generated: Total head generated is actual head, not theoretical.

Formulas

• Force Formula:
  • Force (N) = Density x Rate of Flow x Velocity
• Power Formula:
  • Output Power = (Efficiency x Input Power) / 100
  • Efficiency = Output Power / Input Power
• Monometric Efficiency:
  • Monometric Efficiency = (G x H) / (U x Vw)
  • H = Total Head Generated (Actual Head)
• Peripheral Velocity:
  • U = (π x D x n) / 60 (use outlet diameter)
• Tangential Velocity:
  • Vw = (Gravitational Force x Head) / Monometric Efficiency
  • G = 9.8 m/s²
• Torque Calculation:
  • Torque = Force x Radius
  • Force = Density x Q x Vw

Important Considerations

• Always use outlet diameter for calculations.
• Differentiate between monometric and pump efficiency.
• Use theoretical head when calculating output power with monometric efficiency.

Ventilation Systems

Key Concepts

• Ventilation Pressure: Calculated using the formula PR = K x S x V² / A
• Terms Defined:
  • PR = Initial pressure (Pascals)
  • K = Friction factor
  • S = Rubbing surface
  • V = Velocity (m²/s)
  • A = Area

S Calculations

• S = Perimeter x Length
• Perimeter of a rectangle = 2(L + H)
• Perimeter of a circle = πD

Example Problems

• Calculations involving total head, peripheral velocity, and torque.
• Understanding dimensional analysis when solving problems.

Summary and Conclusion

• Importance of mastering formulas and their applications.
• Future discussions on ventilation systems.

Additional Notes

• Always double-check unit conversions (e.g., liters to cubic meters, minutes to seconds).
• Practice problems provided illustrate practical applications of the formulas.

Note: Ensure to review the lecture material and practice problems for a thorough understanding of centrifugal pumps and ventilation calculations.