Efficient power performance analyses and multi-objective optimizations for closed regenerative gas turbine cycle based on five objectives and NSGA-II

Based on finite-time-thermodynamic (FTT) theory and irreversible closed regenerative gas turbine cycle model established before, the cycle's efficient power (E‾P) expression is deduced, impacts of cycle parameters on E‾P are analyzed. The power, thermal efficiency, E‾P, power density and ecological function are taken as optimization objectives (OOs), heat-conductance (HC) distribution of hot-side heat-exchanger (HSHE) and compressor pressure ratio are taken as optimization variables, and single-, two-, three-, four- and five-objective optimizations for arbitrary combinations of OOs, which are totally 31 combinations, are carried out based on NSGA-II algorithm. The best set of solutions is obtained by comparing deviation indexes of decision-making methods: TOPSIS, LINMAP and Shannon Entropy. Results show that E‾P can be clearly enhanced by improving temperature ratio of heat reservoirs, efficiencies of turbine and compressor, and effectivenesses of regenerator, cold-side heat-exchanger and HSHE. For five-objective optimization, optimal HC distribution of HSHE is distributed between 0.355 and 0.405, mainly distributed between 0.375 and 0.405, and optimal pressure ratio is distributed between 7.5 and 20 for irreversible cycle. Endoreversible case is also provided and compared. The major contributions are introducing E‾P analysis and optimization and performing the five-objective optimizations for regenerative gas turbine cycle by applying the FTT theory and MOO.