1. JET ENGINE PROPULSION
Chapter 1
Compressor Operation

2. The correct name for a jet engine is a
JET ENGINE PROPULSION
The correct name for a jet engine is a
GAS TURBINE ENGINE

3. Compressors THERE ARE TWO TYPES OF COMPRESSOR: AXIAL FLOW CENTRIFUGAL
WE WILL LOOK AT THE AXIAL FLOW COMPRESSOR FIRST.

4. AXIAL COMPRESSOR OPERATION
THE COMPRESSING ACTION CONSISTS OF TAKING A QUANTITY OF AIR AND FORCING IT INTO A SMALLER AND SMALLER SPACE
THIS SQUARE REPRESENTS A QUANTITY OF AIR
THIS SQUARE REPRESENTS THE SAME QUANTITY OF AIR BUT SQUEEZED INTO A SMALLER VOLUME
LET’S SEE HOW THIS IS DONE

5. AXIAL COMPRESSOR OPERATION
SQUEEZE
PUSH BACK

6. AXIAL COMPRESSOR OPERATION
SQUEEZE
PUSH BACK

7. AXIAL COMPRESSOR OPERATION
SQUEEZE
PUSH BACK

8. AXIAL COMPRESSOR OPERATION
SQUEEZE
PUSH BACK

9. AXIAL COMPRESSOR OPERATION
BIG AT FRONT
SMALL AT REAR
THIS IS WHY COMPRESSORS ARE SHAPED THE WAY THEY ARE

10. AXIAL COMPRESSOR OPERATION COMPRESSORS HAVE A SERIES OF ‘STAGES’
FRONT
REAR
COMPRESSORS HAVE A SERIES OF ‘STAGES’
EACH STAGE GIVES A SMALL PRESSURE RISE
OVER THE PREVIOUS STAGE

11. AXIAL COMPRESSOR OPERATION
FIRST
STAGE
ROTOR
STATOR
SECOND
STAGE
ROTOR
STATOR
THIRD
STAGE
ROTOR
STATOR
FOURTH
STAGE
ROTOR
STATOR
FIFTH
STAGE
ROTOR
STATOR
STATOR VANES ARE FIXED TO THE ENGINE CASING
STATORS
ROTOR BLADES ROTATE LIKE PROPELLOR BLADES
ROTOR
FRONT
REAR
FRONT
REAR
EACH STAGE CONSISTS OF A ‘ROTOR BLADE’ IN FRONT OF A ‘STATOR VANE’

12. AXIAL COMPRESSOR OPERATION COMPRESSOR ROTOR BLADES DO THE PUSHING BACK
FRONT
REAR
COMPRESSOR ROTOR BLADES DO THE PUSHING BACK

13. AXIAL COMPRESSOR OPERATION COMPRESSOR STATORS VANES DO THE SQUEEZING
FRONT
REAR
COMPRESSOR STATORS VANES DO THE SQUEEZING
I.E. COMPRESSING
THEY ALSO ENSURE THE AIRFLOW IS PRESENTED TO THE NEXT
SET OF BLADES AT THE CORRECT ANGLE TO INCREASE EFFICIENCY.

14. AXIAL COMPRESSOR OPERATION

15. CENTRIFUGAL COMPRESSOR OPERATION
A CENTRIFUGAL COMPRESSOR IS ONE WHICH TAKES THE AIR IN AT THE
CENTRE OF A DISC AND DISCHARGES IT AT THE CIRCUMFERANCE.
THE VOLUME OF THE IMPELLER IS REDUCED AS THE DIAMETER OF THE
DISC INCREASES
THEREFORE THE PRESSURE INCREASES.

16. CENTRIFUGAL COMPRESSOR OPERATION
TO THE EXHAUST HERE.
VOLUME DECREASES FROM THE INTAKE HERE.
THUS PRODUCING A RISE IN PRESSURE
I.E. COMPRESSION.

17. COMPRESSOR OPERATION
WHENEVER AIR IS FORCED INTO A SMALLER SPACE TWO THINGS HAPPEN
FIRST:- THE PRESSURE OF THE TRAPPED AIR INCREASES
SECOND:- THE TEMPERATURE OF THE TRAPPED AIR ALSO INCREASES
YOU CAN PROVE THESE TWO EFFECTS WITH A BICYCLE PUMP!
IN A JET ENGINE COMPRESSOR, IT IS A CONSTANT FLOW OF AIR
CONSTANTLY BEING COMPRESSED.

18. COMPRESSOR OPERATION