Study on Heat Transfer of Carbon Dioxide in Airborne Thermoelectric Conversion System

To design more effective heat exchange ducts for thermoelectric conversion systems on aircraft, the heat transfer process of a working fluid in a nonuniformly heated square duct was simulated in this study and the influence of the heated wall position was further investigated. Due to the effects of the two main vortex structures in the duct, the highest wall temperature was found in the upper-wall heating case. With increasing working pressure, the influence of the heated wall position on the heat transfer process also increased. When the working pressure was 30 MPa, the wall temperature trend exhibited significant differences in cases with different heated walls, and the maximum wall temperature difference along the duct could be up to 110 K. With an increasing inlet temperature, the influence of the heated wall position on the heat transfer process decreased. Meanwhile, for cases under different pressures (specifically from 8 to 30 MPa), if the inlet temperature was higher than the value at which [Formula: see text] was [Formula: see text], the influence of the heated wall position on the yield strength of the duct also decreased with an increasing inlet temperature.