Turbines Flashcards
Where is the highest heat to metal contact?
HP turbine
What are the different types of turbine blades?
Shrouded
Open ended
What 3 factors contribute to turbine creep?
High temperatures
Fatigue
Centrifugal forces over a long period
How is vibration reduced in the LP turbine blades?
Shrouds
What causes stress rupture cracks in the turbine section?
Turbine creep
When does the active clearance control system operate on engines with a hydro-mechanical fuel control system?
Climb and cruise
What type of duct does nozzle guide vane (NGV) form with adjacent vanes?
Convergent
What methods are used to cool NGV’s and HP turbine blades?
Air tubes
Bypass
Which method is used to cool the LP turbine blades?
Ram air
What is the most common method for attaching turbine rotor blades?
Blade retainers
What advantage does the axial flow turbine have over the radial flow turbine?
Very high airflow
Can have any number of stages
What is the purpose of the turbine?
To drive the shaft that keeps the motion continuous during flight
What are the primary air sources in a passive clearance control system?
Ram air
HP compressor
On engine shut down, what is the contraction sequence for the turbine and the casing?
Rotor shrinks faster than the casing
On what stages of a turbine would open turbine blades normally be found?
Areas of high rotational speed such as the HP turbine
