Multi-scale simulation and optimization on a thermal management system of intermediate circuit and experiment validation

Abstract

In the system-level simulations of heat transfer systems, the characteristics of heat exchangers are often considered constant or used in empirical formulas, which affect the accuracy of the system model. Herein a multi-scale simulation method to analyze the heat transfer characteristics of a thermal management system, including an intermediate loop is proposed. The system model is developed based on the heat current method and flow resistance models. By applying COMSOL LiveLink for MATLAB module, a multi-scale model is obtained, which combines three-dimensional numerical models of the heat exchangers with the system model. Compared to the experimental results, the relative errors associated with the outlet temperatures and heat transfer rate are less than 1.1% and 8.2 %, respectively, thus validating the model. Discussions on the effects of the geometric structure of the heat exchangers on the system show that a plate heat exchanger with 12 plates and a plate spacing of 8 mm is better. For achieving systematic maximum heat dissipation for a certain pumping power consumption, a multi-scale optimization method is proposed by coupling the Lagrange function and numerical model. The results show that the total heat transfer rate improves by 5.89 %, from 8314.81 W to 8804.35 W.

Keywords

• Thermal management system
• Multi-scale simulation
• Heat current model