Learning Module 02:
Types of Gas Turbine Engines
TURBO JET
The basic operating principles of a turbojet engine are relatively straight forward:
- ▸ Air is compressed in the compressor, burned in the combustion chamber, expands and spins the turbine, which in turn drives the compressor (self-sustaining), and leaves the exhaust at high velocities.
- ▸ The difference in velocity in the inlet and exit produces thrust.
📌 EPR – engine pressure ratio, which is the
ratio of turbine discharge pressure to the inlet air pressure
AIRFLOW THROUGH TURBOJET
- ▸ When a compressor and turbine are joined on one shaft, the unit is called a 'spool'.
- ▸ From the compressor, the air is fed directly into the combustion chambers. Fuel is added and the resulting mixture is ignited. The resultant increase in temperature causes a substantial increase in volume.
- ▸ The energy required to drive the compressor is extracted from the stream as it passes through the turbine. The remaining energy in the gas stream acts as thrust as the gases pass to atmosphere via the end of the jet pipe.