Compatibility optimization of a polyhedral-shape thermoelectric generator for automobile exhaust recovery considering backpressure effects

The output performance of thermoelectric generator using thermoelectric modules can be improved by optimizing the heat exchanger structure, but this may cause compatibility issues in the exhaust heat recovery process, such as high backpressure and poor performance for the internal combustion engine. In this study, a polyhedral-shape heat exchanger-based thermoelectric generator system for vehicle exhaust recovery was constructed for the uniform temperature and easy thermoelectric module layout, and the influencing factors of heat transfer and backpressure was evaluated using a realizable k-ϵ turbulence model, and the influence order was analyzed based on the analysis of variance method. Finally, a multi-objective grey wolf optimizer was used to improve the thermoelectric generator system based on the proposed compatibility performance index and optimization objective function. The findings show that the heat transfer performance and backpressure of heat exchanger is obviously affected by different fin length, fin width, fin intersection angle and fin spacing distance. Compared with the empty cavity structure based one and those without optimization, the optimized fin parameters not only obtain high power and satisfactory thermoelectric conversion efficiency, but also ensure low pressure drop and ideal temperature uniformity, which well meets the compatibility requirements for automobile exhaust recovery application.