Abstract:

A simulation study was carried out for the chiller, which is a key component of the secondary loop liquid battery cooling system. The coolant side flow channel was taken as the research object to analyze the influences of corrugated plate structure, coolant mass flow rate and inlet temperature on the flow and heat transfer characteristics. It is found that the second flow generated by the ripple and the contact structure between the upper and lower plates will enhance the turbulence and weaken the thickness of the boundary layer, thus enhancing the heat transfer effect, even when Reynolds number is as low as 739. And, the fitting equation between Nusselt number and Reynolds number showed that average heat transfer coefficient (HTC) of the plate increases with mass flow rate, but this will inevitably enlarge the pressure drop, so it need balance the heat transfer effect and power consumption. In addition, the variation of inlet temperature, which leads to the change of coolant thermal physical properties, caused a slight effect on the HTC and pressure drop. Therefore, the effects of seasonal and operating condition on the heat transfer performance need not consider.

Key words: thermal management of electric vehicles, chiller, numerical analysis, heat transfer, pressure drop, computational fluid dynamics

摘要：

针对双回路液冷电池热管理系统关键部件电池冷却器进行仿真研究，将提取出的冷却液侧流道作为研究对象，分析换热器中波纹板结构、冷却液质量流量与入口温度对于流道内流动及换热的影响。研究发现，波纹及上下板间的触点结构会在流道中产生的二次流，在低Reynolds数（Re=739）下即可达到湍流，增强了换热效果。拟合了板片Nusselt数与Reynolds数的关系式，发现板片的平均传热系数随着质量流量的提高而增加，增幅可达374%，但功耗也随之迅速增加，因而，需要合理选择质量流量以平衡传热与功耗。冷却液入口温度主要通过热物性影响传热系数及压降，但整体影响幅度较小，因而在实际使用中可不考虑季节与运行因素对电池冷却器性能的影响。

关键词: 电动汽车热管理, 电池冷却器, 数值模拟, 传热, 压降, 计算流体力学