Compressors Flashcards
What is the primary function of a compressor?
To supply a sufficient air quantity for combustion chamber requirements
Where does the compressor get air from and where does it discharge it to?
Gets it from air inlet duct and discharges it to the combustion chamber
What is the secondary function of the compressor?
To supply systems requiring bleed air
What is the location of the bleed ports based on?
Pressure and temperature needed
What are the two main components of a compressor?
-compressor rotor
-compressor stator
Describe the compressor stator?
Fixed component with stator vanes to guide and slow airflow to increase pressure
What is the combo of a rotor and stator c@lled?
Compressor stage
What is a compressor stage?
A combination of stator & rotor
What are the two compressor types?
-centrifugal flow compressor
-axial flow compressor (for gas turbines)
What do centrifugal compressors consist of?
-impeller (rotor)
-diffuser (stator)
-compressor manifold
What is the pressure rise per stage Ona centrifugal compressor?
Around 8:1
How many stages are centrifugal compressors limited to and why?
2 due to efficiency concerns
What type of entry can an impeller be on centrifugal compressors?
Single or double entry
What type of engines are centrifugal compressors typically used on?
Turboprop & turboshaft
What does an axial flow compressor consist of?
One or more rotating components that have zero foil shaped blades attached
Why do compressors normally use more than one stage?
As output from a single stage is small
What does increased stages mean for optimal running?
Increased difficulty to optimise
What are centrifugal flow compressors advantages?
-high pressure rise per stage
-efficiency over a wide rotational speed range
-low weight
-simple manufacture
Low cost
Low starting power requirements
What are the disadvantages of a centrifugal flow compressor?
-large frontal area for a given airflow
-losses in turns between stages
What are the advantages of an axial flow compressor?
-high peak efficiencies
-small frontal area for given airflow
-straight through flow allowing for high ram efficiency
-increased pressure rise by increasing the number of stages with negligible losses
What are the disadvantages of axial flow compressors?
-good efficiencies over only a narrow speed range
-difficult to manufacture
-high cost
-relatively high weight
-high starting power requirements
