15.1, 15.3, 15.4 Flashcards
Force
Mass x acceleration
Work
Force x distance
Power
Rate at which work is performed
Work/time
Velocity
Rate if change
Turbo jet vs turbo fan
Turbofan is bypassed
2 parts of a spool
Compressor , turbine
Advantage of high bypass engine
Lower noise level
Specific fuel consumption
Pounds of fuel burned per hour to produce one unit of thrust
Ram ratio
Compression inlet pressure / ambient pressure
Variable geometry intake
Supersonic intake
Where is bell mouth intake used
Helicopter and APU
3 types of subsonic air inlet
Pitot , s duct , bell mouth
Duct best for supersonic engine
CD duct , variable geometry duct , moveable wedge intake
Bifurcated duct
Used on transonic military aircraft
2 types of compressor
Axial flow ; centrifugal flow
Compressor pressure ratio
Pressure of air outside vs inside
Where does pressure rise occur in centrifugal compressor
50% in impeller rest in vaneless space
Advantages of centrifugal compressor
High pressure rise per stage
Good efficiency
Simplicity of manufacture
3 types of axial flow compressor
Single , dual , triple
Spool?
Compressor being driven by a turbine
What is a stage
A complete stage is a row of rotor blades followed by a row of stator blades
Components of axial flow compressor
Rotor , stators, rotor shaft , rotor discs , rotor blades
Compressor stall
Happens when there’s an imbalance of compressor RPM
What happens temp pressure and velocity in a compressor
Temp and pressure increase , velocity decrease
What does air passing through a compressor depend on
Air density , aircraft speed , engine RPM
Effect of temp on pressure rise
Low temp = greater pressure rise
Parts of centrifugal compressor
Impeller rotor , diffuser , manifold
Why are stator vanes shrouded
Prevent vibration
Purpose of bleed valves
Prevent engine surge
Tip clearance control
Cool and hot air contracts or expands tip to maintain clearance
