Jet Propulsion

The Compressor and Turbine

What do the compressors do?

• They take a quantity of air and squeeze it.• Each stage of the compressor is made up from a

rotor blade in front of the stator vanes.

• The compressor is driven by the turbine.• It rotates at a high speed. This adds energy to the

airflow as well as compressing it into a smaller space.

• By compressing the air, the pressure and temperature is increased.

• Compressor blades are aerofoil section which produce lift just the same as a aircraft wing or propeller blade. As the blades rotate they force air rewards into the compressor stators.

• Stator vanes are attached in clusters, or a complete ring to the engine casings, and are similar to the compressor blades in aerofoilsection. These compress the air.

Airflow

FIRST

STAGE

RO

TO

R

STA

TO

R

SECOND

STAGE

RO

TO

R

STA

TO

R

THIRD

STAGE

RO

TO

R

STA

TO

R

FOURTH

STAGE

RO

TO

R

STA

TO

R

FIFTH

STAGE

RO

TO

R

STA

TO

R

Turbine

• The turbine blades are driven by the gas stream passing through them, just the same as the wind drives a windmill.

• They work in the opposite way to Compressor blades.

• There are two types of turbine blade aerofoilsection, Impact and Reaction.

Impact Turbine Blades

• These are driven simply by the weight of the gas stream hitting it.

Reaction Turbine Blades

• The gap between adjacent turbine blades is smaller at the trailing edge compared to the leading edge, and therefore forming a convergent duct.