M15.4 Compressors Flashcards
(55 cards)
Compressor main components
- Stator
- Rotor
Compressor stage
One stator and one rotor
First part of compressor stage
Rotor
A set of stator vanes in front of a compressor stage us called what
Inlet guide vanes (IGV)
IGV purpose
Improve airflow onto the first stage
What are the stator vanes in the fan ducts usually named
Outlet Guide Vanes (OGV)
Types of compressor
- Axial flow
- Centrifugal flow
Centrifugal flow compressor parts
- Impeller
- Diffuser
- Compressor manifold
Centrifugal flow pressure ratio
5:1
Two impellers are mounted face to face is called what
Double face compressor
Benefit of double face compressor
- Weight saving
- smaller engine frontal area
Axial flow compressor stage ratio
1:3:1
Why is the compressor cross section gradually decreased
Constant velocity of the airflow
What is the compressors design point
Optimum condition for a given pressure ratio, rotational speed and airflow
What is a severe form of compressor stall
Compressor surge
What are the effects of compressor surge
- Decrease in thrust
- Engine speed fluctuates
- EGT increases
What area of the compressor is more efficient at low speeds
FWD
Methods to avoid stall or surge
- Compressor bleed valves
- Dual or triple spool rotors
- Variable compressor stator vanes
When do compressor bleed valves open
Low speeds
Where are compressor bleed valves located
Mid or aft
The main disadvantage of compressor bleed valves
Massive loss of efficiency
Advantage of duel or triple spool compressors
Excellent acceleration capability
Most effective method of avoiding compressor stall and surge
Variable stator vanes
Advantage of variable stator vanes
Optimum angle of attack for all speeds
