An open cycle gas turbine, in its simplest form, as shown in Fig. 5.16, consists of a compressor, combustion chamber and a gas turbine which drives the generator and compressor.

In this turbine, the air is first sucked from the atmosphere and then compressed adiabatically (generally in a rotary compressor) and then passed into the combustion chamber. The compressed air is heated by the combustion of fuel and the products of combustion (i.e. hot gases formed by the combustion of fuel) also get mixed up with the compressed air, thus increasing the mass of compressed air. The hot gas is then made to flow over the turbine blades (generally reaction type). The gas, while flowing over the blades, gets expanded and finally exhausted into the atmosphere.

An open cycle gas turbine is also called continuous combustion gas turbine as the combustion of fuel takes place continuously. This turbine also works on Joule’s cycle.