Thermodynamic optimization of the indirect precooled engine cycle using the method of cascade utilization of cold sources

Abstract

To solve the problem of engine performance degradation caused by excessive fuel consumption in the precooled engine cycle, a new optimization method based on the cascade utilization of cold source is proposed, in which the cold sources with different temperature ranges and different working fluids are reasonably matched and adequately utilized. Based on this method, two new optimization cycles are put forward, i.e., the air reheat precooling cycle (ARPC) and the hydrogen reheat precooling cycle (HRPC). To evaluate the performances of these two cycles, a unified model is established. According to the simulation results, the fuel consumption of the HRPC could be reduced by 0–21.04% compared with the traditional precooled engine. Besides, the specific impulse of the HRPC, which can be raised by 16.78% when the heat transfer effectiveness is set to 0.9, is higher than that of the ARPC, which can be increased by 12.64% at most. Moreover, considering the operating constraints, the reduction of the minimum temperature difference of the regenerator and the increase of the pressure recovery coefficient of intake are effective ways to expand the performance boundaries. The results in this paper are beneficial for the performance optimization of the precooled engine cycle.