A gas turbine, also called a combustion turbine, is a type of internal combustion engine. It has an upstream rotating compressor coupled to a downstream turbine, and a combustion chamber in-between.
The basic operation of the gas turbine is similar to that of the steam power plant except that air is used instead of water. Fresh atmospheric air flows through a compressor that brings it to higher pressure. Energy is then added by spraying fuel into the air and igniting it so the combustion generates a high-temperature flow. This high-temperature high-pressure gas enters a turbine, where it expands down to the exhaust pressure, producing a shaft work output in the process. The turbine shaft work is used to drive the compressor and other devices such as an electric generator that may be coupled to the shaft. The energy that is not used for shaft work comes out in the exhaust gases, so these have either a high temperature or a high velocity. The purpose of the gas turbine determines the design so that the most desirable energy form is maximized. Gas turbines are used to power aircraft, trains, ships, electrical generators
par
Nikhil Ashok , Technical Field Advisor , GE Power Service
gas turbine working principle: sucking air from atmosphere
compressing the air in the compressor
mixing the compressed air with fuel gas inside the burner
igniting the same mixture inside combustion chamber and producing the high temperature exhaust gas
guiding the high temperature flow thru the turbine vanes & blades to produce maximum shaft power to drive the generator / coupled machinery.
http://www.youtube.com/watch?v=c12Gh8BN0Io
This is a guite good explanation video, there is a few differencies between turbines regarding the combustor (on the video there is a can system) and the turbine and compressor stage number depends from the field where the turbines are used. The main differencies between turbine types is the maximum power and the effiency. The largest turbines has around360 MW output power and efficency about40% (H class) like Siemens SGT5-8000H. As far as I know the recorder right now is the MHI M701J with470MW /41.0%. If there is more question just let me know.