The Effects of the Combustor Fuel to Air Ratio, Turbine Inlet Temperature, Compressor Bleed Air, Turbine Blade Cooling on the Gas Turbine Performance

One of the most important improvements, the gas turbine has experimented, is the increase of the gas turbine inlet temperature. It has been possible thanks to improvements on the turbine blade cooling techniques, and of course, metallurgical advances. Bleed air is extracted from the compressor for many different purposes like air conditioning, engine start, hydraulic and fuel system pressurization, compressor stall prevention. The specific stage of the compressor from which the air is bled varies by engine type. In some engines, air may be taken from more than one location for different uses as the temperature and pressure of the air is variable dependent upon the compressor stage at which it is extracted. What is common of all compressor bleed is the deterioration of engine performance caused by the extraction. Although, one of the compressor bleeds far from decreases but rather increases the gas turbine engine performance. That is when the colder bleed air is used for the turbine blade cooling increasing the allowable Turbine Inlet Temperature (TIT). In this paper, using our in-house developed thermal mathematical model we examined the negative effect of compressor bleed and the positive effect of the extracted bleed air used for the turbine blade cooling comparing its negative and positive effect on the engine performance.