1. Performance Analysis of Multi Stage Axial Flow Compressors
P M V Subbarao
Professor
Mechanical Engineering Department
Design of Performance….

2. Irreversible Stage of an Axial Flow Compressor
T03=T02
T02s
Rotor Losses
Total Losses
T03s T
p01
T01 s

3. Thermodynamics of Irreversible Compressor

4. Stage Efficiency
The stage efficiency of an adiabatic compressor stage is:
For calorically perfect gas

5. Power input to the compressor :
Inlet Velocity Triangle
Outlet Velocity Triangle
Current Practice:
Theoretical Power input to the compressor:

6. For an isentropic compressor:

8. Polytropic Stage Efficiency
The ratio of the ideal specific work input to actual specific input for a differential pressure change

9. For a differential isentropic compression
Integrating for the complete stage

11. Loss Factors in an Irreversible Compressor stage
Cascade testing gives the values of these loss factors.
General value of Loss factors:

12. Conservation of Rothalpy
Define the rothalpy which is constant throughout the rotor.
The rothalpy is useful for calculating the outlet conditions of the rotor.
For an isentropic rotor

13. Relative total pressures & Total Temperatures

14. Current Design Practice
Fan or low pressure Compressor
Parameter
Range
Pressure ratio for single stage
1.5 – 2.0
Pressure ratio for two stages
2.0 – 3.5
Pressure ratio for three stages
3.5 – 4.5
Inlet mass flow rates
195 – 205 kg/m2.s
Tip speed
427 – 457 m/s
Diffusion factor
0.5 – 0.55

15. Current Design Practice
High pressure Compressor
Parameter
Range
Stage loading coefficient
0.3 – 0.35
Flow coefficient
0.45 – 0.55
Hub/tip ratio
0.6 – 0.75
Inlet mass flow rates
175 – 185 kg/m2.s
Tip speed
386 – 457 m/s
Diffusion factor
0.5 – 0.55

17. Compressor Maps

18. Reciprocating Engine Vs Jet Engine

20. Fire is An Accident… How to make it More reliable Resource….

21. Laws of Combustion
A Special Device is required to hold the flame, called Burner.
The maximum quantity of fuel that can be handled by a single burner is limited.
The maximum allowable air to establish efficient combustion of a given amount of fuel is limited.
The maximum temperature due to efficient combustion is always higher than the maximum safe temperature: limited by turbine blades.
Infra structure should be provided to facilitate these conditions.

22. Requirements of A Reliable Combustion
MATtr Theory
Mixing: Fuel preparation systems.
Air: Draught systems.
T : Preheating of fuel.
t : Dimensions of combustion chamber.
r: Turbulence generation systems.