Braysson heat engine; Multi-irreversibilities; Specific power output; Thermal efficiency; Optimally operating region; Optimum criterion
An irreversible cycle model of a Braysson heat engine operating between two heat reservoirs is used to investigate the performance of the cycle affected by the finite-rate heat transfer between the working fluid and the heat reservoirs, heat leak loss between the heat reservoirs and irreversibility inside the cycle. The specific power output is maximized with respect to the cycle temperatures along with the isobaric temperature ratio. The specific power output is found to be a decreasing function of the internal irreversibility parameter and isobaric temperature ratio while there exist the optimal values of the state point temperatures at which the specific power output attains its maximum value for a typical set of operating parameters. Moreover, the maximum specific power output and other cycle parameters are calculated for different sets of operating conditions. The optimally operating regions of the important parameters in the cycle are determined. The results obtained here may provide some useful criteria for the optimal design and performance improvement of a realistic Braysson heat engine.