Turbine Air Inlet

Question 1

Air intake

Answer 1

Convergence at the beginning and then diverge

Question 2

Air intake

Answer 2

The lip is shaped to reduce flow separation in crosswinds and high angle of attack.
The throat is slightly convergent duct leads to the diffuser.
The diffuser generates an increase in pressure at the compressor inlet

Question 3

Intake instability

Answer 3

Crosswind across the face of the intake can disrupt the smooth inflow and lead to a hot or hung start.
A strong cross wind at the start of the take off can cause inlet instability and surge
Risk reduced by carrying out a rolling take off

Answer 4

~at low speeds and high power settings the air entering the inlet may approach mach1
The inlet becomes choked

~at high speeds excess air spills over the lip
~above about 0.85mach ,shock waves may from as the air acclerates through the intake throat

Question 5

Intake icing

Answer 5

~disrupt the laminar flow of air into the engine
~can starve the enigne of air causing flame out
~can damage the blades if ice breaks off
~the lip is heated ,usually with bleed air or oil from the enigne