Analysis of Combined Effects of Air Transpiration Cooling and Evaporative Inlet Air Cooling on the Performance Parameters of a Simple Gas Turbine Cycle

This paper is focused on accessing the benefits of incorporating an air humidifier with a cooled gas turbine cycle. Air transpiration cooling has been adopted as the cooling technique for gas turbine blades. A parametric study of the effect of compressor pressure ratio (r(p,c)), compressor inlet temperature (CIT), turbine inlet temperature (TIT), inlet temperature ratio (r(IT)), ambient relative humidity, and ambient temperature on performance parameters of plant has been carried out. Evaporative inlet air cooling has been observed to improve the plant efficiency of a transpiration cooled gas turbine plant by 4.84% and plant specific work by 9.68% at an ambient temperature of 313 K and ambient relative humidity of 0.2. The effects of variation of ambient parameters on cycle performance are found to be more pronounced at higher turbine inlet temperature and higher compression ratio (r(p,c)). The work ratio increases with an increase in the value of r(IT) up to 5.6 after which it decreases. There exists an optimum r(IT) at any r(p,c) with reference to the maximum work ratio. The heat rate increases with an increase in r(IT) and a decrease in r(p,c). For all values of TIT there exists an optimum r(p,c) at which plant efficiency is at its maximum. (C) 2014 American Society of Civil Engineers.