The Rolls-Royce Avon is a turbojet engine that has been widely used in various aircraft, including military jets such as the English Electric Canberra and the de Havilland Comet. The thermal efficiency of a turbojet engine is a measure of how effectively the engine converts the chemical energy in fuel into useful work, primarily in the form of thrust. The thermal efficiency is defined as the ratio of the useful work output to the energy input from burning the fuel.
The thermal efficiency is expressed mathematically as:
where:
- is the thermal efficiency,
- is the thrust produced by the engine,
- is the jet velocity,
- ṁf is the mass flow rate of fuel,
- is the specific enthalpy of the fuel.