Feasibility study on applying thermoelectric SiC ceramics for supersonic aerodynamic heat recovery

Abstract

SiC ceramics are widely serving as ceramic composites matrix materials of high-velocity vehicles structures against extremely heating and oxidation for their sustainability at high temperature, and are also high temperature thermoelectric materials, which can transfer heat to electricity by temperature difference. Both of these advantages brought out an idea of generating electricity from aerodynamic heat by thermoelectric SiC structures on supersonic vehicles. A simple nose-tip thermoelectric module is set up, in this work, to predict the thermoelectric performance of SiC ceramics in a supersonic air flow environment (Mach number 3). The flow field parameters, temperature difference and temperature distributions of the module have been simulated by computational fluid dynamics methods. The thermoelectric performance and effect of Thomson heat were discussed. The maximum power output and energy efficiency reaches 0.0027 W and 0.0036 %, respectively, at 230 K temperature difference and a current of 0.122 A. The Thomson heat increases directly with the output current, and at a current above 0.15 A, over 50 % of the generated power has been turned back to thermal heat, resulting in the effective output power as well as energy efficiency decrease rapidly. The thermoelectric efficiency would be increased on higher-speed vehicles by enlarged temperature difference.