Performance analysis of fuel vapor turbine and closed-Brayton-cycle combined power generation system for hypersonic vehicles

One of the most important targets is the power supply issue in hypersonic propulsion systems with long range/ endurance. Due to the lack of rotating components and aerodynamic loss using the free stream, existing tech- nologies of onboard power generation are hardly applicable on hypersonic vehicles using scramjets. A combined power generation system based on fuel vapor turbine (FVT) and closed-Brayton-cycle (CBC) is proposed in this article. To evaluate the system performance, a zero-dimensional model is established, and an optimization method based on genetic algorithm is developed to obtain the maximum electric power. Results indicate the increase of the compressor pressure ratio has the most significant effect on rising the electric power. And the effect of the FVT expansion ratio becomes significant when the FVT isentropic efficiency gets high. Furthermore, due to the utilization of the fuel vapor pressure energy by the FVT, the electric power of the FVT-CBC combined system is higher than that of the CBC independent power generation system, with a rise percentage of 25%- 190%. After optimization, the maximum electric power of the combined system can be 326.7 kW. In a word, the FVT-CBC combined power generation system can supply sufficient power for hypersonic vehicles.