Cooling and power generation performance evaluation of thermophotovoltaic system for hypersonic vehicle engines

Abstract

The development of hypersonic vehicles is challenging owing to their high cooling and power demands. To address this challenge, this paper proposes a thermophotovoltaic power-generation system for hypersonic vehicle engines that can generate power while providing thermal protection. Thermophotovoltaic cells are installed on the wall of the combustor cooling channels, through which the fuel flows to cool the cells. The photons emitted by the high-temperature emitter are filtered through a filter and reach the cell to generate electricity. A heat transfer and power generation model, including the combustor, thermophotovoltaics, and cooling channels, was established and iteratively solved until energy conservation was satisfied. The impact of different incoming Mach numbers, fuel flow rates, inlet temperatures, and starting positions on the cooling and power generation performance of the system was analyzed. The proposed thermophotovoltaic power-generation system reduced the weight of the combustor by 2.43 % at a combustor length of 3.12 m. The heat flux on the combustor wall in the section where thermophotovoltaics are arranged can be reduced by nearly 2/3, with the total thermal protection demand reduced by about 1 MW at Ma 7. The peak of the power generation density curve reached 58 kW/m², generating 175.75 kW of electricity at Ma6 incoming flow, a 6 kg/s fuel flow rate, and a 263.15 K fuel inlet temperature. The power-to-weight ratio was 0.88, and the net heat-to-power conversion efficiency of the system reached 10.5 %. This research provides a reference for heat-to-power conversion technology of hypersonic vehicles at high flight Mach numbers.