15.04 Compressors Flashcards
What are the two ways to compress air in an engine?
- Decrease the volume of a cylinder using a piston.
- Make use of Bernoulli’s principle to get compressed air.
What two main parts make up the compressor?
Stators and rotors.
How are the rotor blades used?
They rotate around the axis and suck in the air to energise the airflow.
How are the stator vanes used?
They guide and slow the airflow to increase the pressure.
What is another name for a combination of the stator and rotor ?
Compressor stage.
What do the compressor inlet and outlet cases provide?
support for the compressor rotor bearings, and they improve and straighten the airflow.
What are the two types of compressor?
Axial flow and centrifugal.
Main components of a centrifugal compressor ?
- the impeller
- the diffuser
- the compressor manifold.
Where are you most likely to find a centrifugal compressor?
Small gas turbine engines (APUs)
What is the compressor ratio of a centrifugal compressor ?
5:1
What is a double entry type impeller?
Two impellers mounted back to back, also known as double face compressor, to increase airflow and save weight by having a smaller engine frontal area.
What is the pressure ratio of each stage of an axial flow compressor?
1.3:1
in an axial flow compressor, why are many stages needed?
The pressure increase at each stage is very small.
What are the advantages of an axial flow compressor?
- More efficient at optimum speeds.
- Less aerodynamic drag.
- Addition of many stages creates the ability to reach very high pressures.
What are the advantages of a centrifugal flow compressor?
- Less power needed for engine start.
- less weight.
- simpler and less expensive.
- high pressure increase at each stage.
