Efficiency Enhancement in Pressure Gain Combustion Combined Cycle Gas Turbine by Blade Cooling Integration with Bottoming Cycle

This paper investigates the potential advantages of integrating turbine blade cooling with bottoming cycle in Combined Cycle Gas Turbine (CCGT) with Pressure Gain Combustion (PGC) for land-based power generation application. PGC is represented by a steady-state zero-dimensional constant volume combustion (CVC) model based on the Humphrey cycle. The PGC combustor model is simulated with different injection pressure losses to investigate the impact of pressure gain on steam cooling integrated CCGT. Different approaches of turbine blade cooling through the bottoming cycle are investigated in this work, such as (i) cooling of compressor bleed air through steam/water, ii) open-loop steam cooling (OLSC) for stator and vanes, iii) closed-loop steam cooling (CLSC) for stator and vanes and iv) mixed loop steam cooling (MLSC) where stator is steam cooled while rotor is air cooled. Results showed that implementing both PGC technology and steam cooling together in a CCGT can significantly enhance efficiency and work output due to the synergistic effect of both technologies. The efficiency of an H-class CCGT can be increased from 62.6 to 67.2% (4.54 percentage points increment) and specific work by 194.5 kJkgair by using CLSC and PGC combustor with a pressure gain of 0.40. MLSC was identified as the most practical solution, which, when augmented with a PGC combustor with 0.26 pressure gain, can improve the overall CCGT efficiency by 2.9 percentage points and specific work by 104.6 kJ/kgair.