Effects of physical dimensions, temperature ranges and interfacial thermal contacts on the multi-stage thermoelectric generators for a hypersonic vehicle

The conversion and utilization of aerodynamic heat is one of the most promising thermal management techniques for hypersonic vehicles. In this paper, one-, two- and three-stage thermoelectric generators (TEGs) are designed and the effects of physical dimensions, temperature ranges and interfacial thermal contacts are studied for a hypersonic cruise vehicle. First, the geometric parameters of TEGs are optimized, and the optimal physical dimensions under different temperature ranges are obtained in consideration of both power supply and weight increment. Second, the effects of interfacial thermal contacts between TE and electrode materials are studied considering the contacting pressure, temperature and gap medium by two-scale simulations, the thermal contact resistance in micro roughness-scale and the TE performance of TEGs in meso layer-scale. Finally, the TEG is considered as a multi-functional thermal protection structure, and its power generation capacity and weight increment cost are evaluated for a typical hypersonic cruise vehicle. The results show that for different temperature ranges there exist optimal physical dimensions, and greater contact pressure and stronger thermal conduction property of gap medium result into better performance of TEGs.