Thermodynamic analysis for a novel steam Rankine cycle based indirect chemical precooled engine used for supersonic flight

Chemical precooling technology is an effective way to improve flight speed for supersonic precooled engine cycle. To solve the problem of pipe blockage caused by the fuel coking in the pre-cooler, a new indirect chemical precooled engine combined with the steam Rankine cycle (SRC) is proposed, from which the chemical reaction is transferred from pre-cooler to regenerator. To evaluate engine performances, a thermodynamic model is developed and an experimental platform is established to obtain the fuel heat sinks. The simulation results indicate that the performances and operation range of SRC based engine are significantly higher than that of traditional Brayton cycle based engine. Further, the upper and lower boundaries of specific impulse and thrust correspond to the maximum and minimum values of fuel chemical reaction degree respectively. Moreover, the optimal values of water mass flow, turbine inlet temperature and compressor pressure ratio could be obtained at the point where the fuel is fully cracked. Finally, the SRC based engine could improve the specific thrust by 46.43–64.54% compared with the traditional ramjet, but the specific impulse is slightly lower than that of traditional turbojets and ramjets. In general, the results in this paper are beneficial for developing high-performance turbine combined engines.