Lecture Notes on Aero Engines and Basic Gas Turbine Cycle

Introduction

• Discussion on student participation and online access (Teams and YouTube).
• Class held in a strange situation due to COVID-19—emphasis on efficient teaching.

Course Organization

• Schedule: 4.5 hours on Thursday and Friday afternoons until December.
• Structure:
  • 3 hours of theory followed by 1.5 hours of exercises.
  • Exercises handled by assistants Joël Vincay and Mariano Di Matteo.
• Content Overview:
  • Two main parts:
    1. Aero Engine Cycles
    2. Components of Aero Engines
  • An intermediate part on working points and lines.

Course Breakdown

1. Aero Engine Cycles:
   • Study of different thermodynamic cycles.
   • Historical overview of existing and past cycles.
2. Working Points and Lines:
   • Overview of engines from a holistic view rather than detailed component analysis.
   • Definition and significance of working points and lines.
3. Components of Aero Engines:
   • Detailed analysis of components from intake to exhaust.
   • Challenges and important physical parameters in each component.

Assessment Structure

• Exam Format:
  • 50% theory and 50% exercises.
  • Exercise component completed on paper.
  • Oral exams with prepared questions from a list provided in advance.

Basic Gas Turbine Cycle Overview

• Definition: Study of the simplest gas turbine engine cycle.
• Components:
  • Turbine driven by a high energy flow.
  • Importance of mass flow rate over volumetric flow rate.
  • Necessity of a combustion chamber for continuous energy flow.
  • Role of compressor to increase pressure for combustion.

Working Mechanism

• **Flow Process:
  1. High energy flow enters turbine.
  2. Turbine generates work, creating torque.
  3. Torque drives compressor, increasing pressure.
  4. Combustion chamber ignites fuel-air mixture, increasing temperature.
  5. Flow expands in turbine, exiting at atmospheric conditions.**

Important Parameters

• Pressure and Temperature Requirements:
  • High temperature required for combustion efficiency.
  • Low exit pressure from the turbine is crucial for effective engine operation.

Applications of Gas Turbine Cycle

• Used in both aeronautical applications and electricity generation.
• Power-to-Mass Ratio:
  • Significant in lightweight applications such as aircraft engines.
• Durability:
  • Low friction design leads to extended life cycles.

Computational Analysis in Gas Turbine Engines

1. Undesigned Computation:
   • Compute working point based on real measurements.
2. Optimization:
   • Analyze how to improve performance parameters.
3. Design Point:
   • Define the optimal operating conditions based on earlier computations.
4. Off-Design Study:
   • Essential to understand performance in varying operational conditions.

Conclusion

• The basic gas turbine engine serves as a foundation for all cycles studied in future lectures.
• The versatility and efficiency of gas turbine engines position them as a critical technology in various applications, especially aerospace and energy production.

Next Steps

• Short break before resuming with undesigned computations and cycle analysis.