A simple cycle gas turbine consists of a (1) compressor, (2) combustion chamber and (3) gas turbine.
In the open cycle gas turbine, ambient air enters at the compressor and after the compression of air, fuel is burned in the air itself to raise it to high temperature and then product of combustion are passed on to the turbine for expansion. After delivering the work combustion products are finally rejected to atmosphere. In the open cycle the working medium is continuously replaced by fresh air and fuel. It works on the joule cycle and Brayton cycle.
The air is sucked in by the compressor from the atmosphere through the filter which removes the dust from the air. The rotary blades of the compressor push the air between the stationary blades to raise its pressure to 4-5 atmosphere. Hence the air is available at high pressure at output of the compressor. Then high pressure air passes through combustion chamber, in which heat added to the air at constant pressure by burning the fuel and raises temperature (about 1650) of working medium. This high temperature must be brought down to the level so that the thermal stresses in the turbine blades do not become excessive. This is achieved by allowing the reminder air to enter the combustion chamber at downstream to mix and cool down the combustion gases. The products of combustion comprising of mixture of gases at high pressure and temperature are passes through the gas turbine. These gases in passing over the turbine blades expand and thus result in motion of rotor and finally discharged to the atmosphere at the temperature about 540.