Gas Turbine

Gas turbine or combustion turbine is a rotary engine that extracts energy from a flow of combustion gas. It has an upstream compressor coupled to a downstream turbine, and a combustion chamber in-between. It may also refer to the turbine component.

Energy is added to the gas stream in the combustor, where fuel is mixed with air and ignited. In the high pressure environment of the combustor, combustion of the fuel increases the temperature. The products of the combustion are forced into the turbine section. There, the high velocity and volume of the gas flow is directed through a nozzle over the turbine’s blades, spinning the turbine which powers the compressor and, for some turbines, drives the mechanical output. The energy given up to the turbine comes from the reduction in the temperature and pressure of the exhaust gas.
  Gas turbines are described thermodinamically by the Brayton cycle, in which air is compressed isentropically (equal), combustion occurs at constant pressure, and expansion over the turbine occurs isentropically back to the starting pressure.


Types of gas turbines are jet engines, aeroderivative gas turbines, amateur gas turbines, auxilliary power units, and industrial gas turbines. Airbreathing jet engines are gas turbines optimized to produce thrust from the ehaust gases, or from ducted fans connected to the gas turbines. Jet engines that produce thrust primarily from the direct impulse of exhaust gases are often called turbojets, whereas those that generate most of their thrust from the action of a ducted fan are often called turbofans or (rarely) fan-jets. Gas turbines are also used in many liquid propellant rockets, the gas turbines are used to power a turbopump to permit the use of lightweight, low pressure tanks, which saves considerable dry mass.

Aeroderivative gas turbines are also being used in electrical power generation due to their ability to...