Intakes and Inlets Flashcards
What are the two engine functions of the inlet
1st: To recover as much of the total pressure of the free stream air as possible and deliver this pressure to the front of the engine with a minimum loss of pressure and correct speed.
“Ram recovery”
2nd: The inlet must uniformly deliver air to the compressor inlet with as little turbulence and pressure variation.
What is the aircraft function of the inlet?
Minimum drag on the aircraft.
Which is the most common air intake for subsonic aircraft or low supersonic aircraft.
Fixed geometry (Pitot type)
Why are intake designs normally divergent?
To reduce speed and increase pressure.
What are the types of inlet and duct types?
Wing Root
Side Inlet
Simple
Fin
What is a vortex dissipator?
Typically installed on pitot-type ducts. To destroy any vortices that are created by the engine sucking air from directly below the intake lip, done by squirting high-pressure air into the vicinity of the vortex.
What are supersonic intakes designed to do?
Reduce airflow to subsonic speed and increase pressure prior to entry to the compressor.
External/Internal compression intake.
Explain the Variable inlet?
Used for supersonic aircraft it has a variable throat area and spill valves to help accommodate and control the changing volumes of air.
The variable throat intake varies with aircraft speed and positions the shockwaves accordingly to decrease air velocity and maintain maximum pressure recovery.
Explain the divergent duct/Inlet Diffuser?
An inlet diffuser.
It has more of an effect on pressure, as it slightly increases static pressure allowing for the air to arrive at the engine with minimal turbulence and at a more uniform pressure.
Explain a fixed inlet?
It is a fixed cone that forms a shockwave across the intake corresponding to subsonic airflow produced downstream through the intake ducting.
What is the purpose of the bird-catcher/sand separator?
Intend to remove any dirt/dust particles by relying on air being lighter and the heavier particles duct overboard via a tounge.
How does the Engine air particle separate works? “EAPS”
Uses vanes creating a vortex in a tube, the centrifugal force separates any particles from the clean air.
