Numerical investigation of a thermoelectric generator system with embedded sickle-shaped fins

Abstract

To enhance the utilization efficiency of exhaust gas in thermoelectric generator (TEG) systems, a polygonal heat exchanger with embedded sickle-shaped fins was proposed in this study. A coupled fluid-thermal-electric multiphysics numerical model was developed to analyze the impact of different fin variables on system performance. Subsequently, the established model was validated on a test bench. The results indicate that embedded sickle fins significantly improve the TEG performance. Higher fins enhance the system's output power and temperature uniformity, albeit with increased pressure drop. Conversely, elongated linear fins and increased arc fin radius decrease pressure drop but reduce its output power. Additionally, increasing the end angle of the arc improves temperature uniformity with minimal effect on output power and pressure drop. Moreover, the TEG system exhibits optimal performance when the linear fin length is 180 mm, the height is 45 mm, the radius of arc fins is 305 mm and the end angle is 8°. At the inlet air temperature of 600 K and the velocity of 40 m/s, the TEG output power, temperature uniformity coefficient and pressure drop for this configuration are 116.59 W, 0.99 and 845 Pa, respectively. This work contributes a theoretical reference for the structural optimization of low-backpressure TEG systems in future automotive exhaust applications.