Heat Transfer Performance Analysis And Structural Optimization Of The Heat Exchanger In Automobile Exhaust Thermoelectric Power Generation System

In recent years,with the problems of the worldwide energy shortage and environmental degradation,the thermoelectric technology has attracted great attention around the world as an environmentally friendly energy technology.And many scholars have done a lot of exploration and research on thermoelectric theory and application.In the automobile exhaust thermoelectric power generation system(AETPGS),in order to maximize the thermoelectric conversion efficiency as far as possible,it is necessary to collect and delivery automobile exhaust waste heat efficiently.The heat exchanger is the main component of energy transfer in AETPGS.Thus,to fully exploit its potential of waste heat recovery is the key to improve the thermoelectric conversion power.In this paper,based on the structure of the AETPGS and the working environment of the heat exchanger,the service conditions of the heat exchanger and thermoelectric modules(TEMs)are simulated by using the fluid-solid interaction model.The thermal performance is discussed and structural optimization of the fins is carried out.The main contents in the paper are as follows:(1)Based on the working environment of the heat exchanger,the service conditions of the heat exchanger and TEMs are simulated by using the fluid-solid interaction model.The temperature field and pressure field of the heat exchanger with TEMs are studied by contrast with the case of heat exchanger exposed in air.And the effect of the TEMs’endothermic effect on the heat exchanger is discussed and evaluated comprehensively.The results show that the endothermic effect of the TEMs has a great influence on the thermal field distribution of the heat exchanger.And the actual working condition can be reflected more accurately by the way of considering the endothermic effect of the TEMs.Besides,the heat exchanger with same internal structure has different heat transfer performance and exhaust back pressure under different working conditions.Through the comparison of different working conditions,it can be found that choosing the common working condition of the car is more reasonable to optimize the internal fins of the heat exchanger.(2)Based on the common working environment of the heat exchanger,the fluid-solid interaction model of the heat exchanger and TEMs is established for surrogate model and numerical optimization method.That is,guaranteeing the exhaust back pressure within the acceptable limit of 1500Pa and taking heat transfer power,average temperature and temperature uniformity as optimization goals,the surrogate-model-based optimization is introduced to optimize the internal fins for a high-efficiency heat exchanger.The results show that optimization design of fin structure has a bigger heat transfer power(increased from 4201.3W to 4908.5W),a higher average temperature(increased from 416.7K to 427.4K)and a more homogeneous temperature distribution(uniformity coefficient decreased from110.7K~2 to 93.8K~2)compared with the initial design while maintaining the original premise of exhaust back pressure.It significantly improves the heat transfer performance and heat recovery efficiency.