Performance evaluation of steam injected gas turbine based power plant with inlet evaporative cooling

Highlights: • Steam injection in the combustor increases expanding mass in the gas turbine. • Gas turbine (GT) cycle with SI produces 7.2% more sp. work output than a simple cycle. • GT cycle with IEC & SI produces 9.5% more sp. work output than a simple cycle. • GT cycle with IEC, SI & FC produces 10.1% more sp. work output than a simple cycle. - Abstract: Present paper deals with the study for performance evaluation of steam-injected gas turbine (STIG) based power plant with inlet evaporative cooling. It investigates the combined effect of inlet evaporative cooling (IEC), steam injection (SI) and film cooling (FC) on the power augmentation of simple gas turbine cycle. Thermodynamic modeling has been carried out and presented along with results showing the influence of inlet evaporative cooling on various performance parameters of STIG based power plant. Results show that there occurs increment of 3.2% in cycle thermal efficiency due to lowering of the compressor inlet temperature from 318 K to 282 K at 5% steam to air ratio (SAR). At 1850 K turbine inlet temperature and cycle pressure ratio of 24 there occurs increase in thermal efficiency of the GT cycle with IEC, SI and FC as compared to the simple GT cycle. Injection of steam in the combustion chamber enhances the specific expansion work in the gas turbine, which increases at rate of 2.95% for every increase in SAR by 2%. The study shows that gas turbine cycle configuration with inlet evaporative cooling (IEC), steam injection and film cooling is the best combination for obtaining more efficiency and power.