Development of two transient models for predicting dynamic response characteristics of an automobile thermoelectric generator system

In this work, two transient models, including a transient fluid-thermal-electric multiphysics numerical model and a hybrid transient CFD-analytical model, are proposed to predict the dynamic performance of the automobile thermoelectric generator system in practical applications. The transient models consider the heat source fluc-tuation, temperature dependence of thermoelectric materials, and the coupling of different physical fields, which can simulate the actual working conditions. According to the model results, the dynamic output power varies smoothly and is mainly related to the exhaust temperature due to thermal inertia, whereas the dynamic con-version efficiency fluctuates sharply and is mainly related to the exhaust mass flow rate. Compared with the transient fluid-thermal-electric multiphysics numerical model, the output performance obtained by the hybrid transient CFD-analytical model is overestimated, especially for conversion efficiency, and the average errors of output power and conversion efficiency between the two models are 2.90% and 13.58% respectively. Besides, the output performance predicted by transient models is lower than that expected in a steady-state analysis, and the transient models are experimentally verified. This work fills the gap of theoretical models for predicting the dynamic response characteristics, and the findings are helpful to understand the transient performance of automobile thermoelectric generator systems.

Automated summary

In this study, two transient models, a transient fluid-thermal-electric multiphysics numerical model and a hybrid transient CFD-analytical model, are proposed to predict the dynamic performance of automobile thermoelectric generator systems. The models consider the heat source fluctuation, temperature dependence of thermoelectric materials, and the coupling of different physical fields. The results show that the dynamic output power is mainly related to the exhaust temperature due to thermal inertia, while the dynamic conversion efficiency is mainly related to the exhaust mass flow rate. The hybrid model overestimates the output performance, particularly the conversion efficiency, with average errors of 2.90% and 13.58% for output power and conversion efficiency, respectively, compared to the numerical model. The transient models predict lower output performance compared to steady-state analysis, and the models are experimentally verified. This work fills a gap in theoretical models for predicting the dynamic response characteristics of automobile thermoelectric generator systems.