Flow Loss Analysis and Structural Optimization of Multiway Valves for Integrated Thermal Management Systems in Electric Vehicles

The multiway valve is the core component of the integrated thermal management system in an electric vehicle, and its heat transfer loss and pressure loss significantly impact the performance of the whole thermal management system. In this paper, heat transfer loss and pressure loss in multiway valves are investigated using three-dimensional unsteady numerical simulations. Heat transfer loss and pressure loss under different operating modes are revealed, and relationships between pressure loss and mass flow rate, inlet temperature, and valve materials are studied. The results show that the significant temperature gradient around the control shaft results in heat transfer loss and pressure loss mainly occurs around the junction of the control shaft and the shell, where the flow direction changes sharply. The pressure loss is nonlinearly and positively correlated with the mass flow rate. Furthermore, the main geometric parameters of the pipeline and the control shaft are optimized. The pressure loss firstly increases and then decreases, with the increasing curvature of the inner walls of the pipe corners in four flow channels. Compared with the structural optimization at the pipe corners, increasing the curvature of the inner wall of the control shaft and the shell corners reduces pressure loss continuously. Moreover, this study obtains an optimal structure with minimum pressure loss using coupled structure optimization at the control shaft and shell corners.