What is the primary function of the turbine in a gas turbine engine?
Convert kinetic energy of exhaust gases into mechanical energy to drive the compressor and accessories
How much exhaust gas pressure energy is absorbed by gas generator turbines?
Approximately 60–70%
What factors determine how much energy a turbine absorbs?
Load on the turbine including compressor size/type, accessories, and other turbine stages
What components can turbines drive in gas turbine engines?
Low-pressure compressors (fans), propellers, and shafts
Where is the turbine located in a gas turbine engine?
Directly downstream of the combustion chamber
What are the two main types of turbines?
Radial flow turbines and axial flow turbines
What is a key characteristic of a radial flow turbine?
It is always single-stage
Where are radial flow turbines commonly used?
Small engines such as APUs
What are the advantages of radial flow turbines?
Simple design and easy manufacturing
What are the disadvantages of radial flow turbines?
Low airflow and lower efficiency due to aerodynamic losses and centrifugal forces
What type of turbine is used in modern gas turbine engines?
Axial flow turbine
Why are axial flow turbines preferred in modern engines?
They handle high airflow and produce high thrust
Why can axial flow turbines have multiple stages?
To drive compressors, accessories, and large fans
What is the function of nozzle guide vanes?
Accelerate and direct exhaust gas toward turbine rotor blades
How does gas produce torque on turbine blades?
By impacting the rotor blades and causing rotation
What defines an impulse turbine?
Rotation caused only by the impact of gas on rotor blades
Where does the pressure drop occur in an impulse turbine?
In the nozzle guide vanes
How does gas behavior change in impulse turbine nozzles?
Velocity increases and pressure decreases
What force acts on impulse turbine blades?
Impulse force from gas impact
What defines a reaction turbine?
Rotation caused by gas expansion and acceleration on the blades
Where does pressure drop occur in a reaction turbine?
Along the rotor blades
What is a reaction-impulse turbine?
A turbine combining both impulse and reaction characteristics
How is power distribution achieved in reaction-impulse blades?
Impulse at the root and reaction at the tip
In what plane do turbine blade forces act?
In the plane of rotation
