Thermodynamic Performance Prediction of Air-Film Blade Cooled Gas Turbine Based Cogeneration Cycle for Marine Propulsion Applications 2018-01-1364
Cogeneration involves simultaneous production of both thermal energy as well as electrical energy from a single energy conversion system. The thermal energy produced by the system is generally in the form of steam and generally used for process heating purposes. Marine gas turbine that provide propulsive power also have thermal energy in it exhaust gas stream which can be further be used to generate steam for process heating applications. Gas turbine blade cooling is critical to reliable operation of gas turbine based power utilities. A thorough literature review suggests that air-film cooling is one of the most widely used blade cooling techniques. The present study adopts few previously developed air-film cooling based gas turbine blade cooling models (without considering radiative heat transfer) and compare them with a proposed gas turbine model (which consider radiative heat transfer to gas turbine blade surface).
Also the study focuses to extend this article towards analysis of gas turbine based cogeneration cycle with single-pressure heat recovery steam generator. Results have been plotted based on proposed model in terms of blade coolant mass fraction, gas turbine cycle specific work, fuel utilization efficiency, power-to-heat ratio, which are the function of both compressor pressure ratio and turbine inlet temperature. The paper also describes the possibilities of improvements in gas turbine efficiency and power output by advancement in blade material technologies. The paper further reports results of exergy analysis to highlight component-wise exergy destruction. The second law efficiency for the gas turbine has been found to be ≈ 35% (at TIT =1750K) while combustor is the cycle component with maximum exergy destruction.