液冷系统中均热板气液相变的热质传输模拟

Numerical simulation of the heat and mass transfer inside a vapor chamber in a liquid cooling system

摘要:

为提高电池热管理液冷系统的均温性,研究一种铝槽式均热板和直流式液冷板相结合的复合液冷系统,并建立相应的三维传热模型。采用Volume-of-fluid(VOF)多相流模型,模拟均热板槽道内丙酮工质的气液相变过程,以及与液冷流道的耦合传热过程,并将模拟结果与实验结果进行了对比,验证了模型的正确性。研究结果显示,均热板可以提高液冷系统散热过程中的均温性,加热表面的温差可以控制在2.72 K以内。通过机理分析发现,其原因与均热板内部气液工质的热质传输过程有关。在液冷系统冷却液沿程温升的影响下,均热板腔室中的丙酮气相工质在长度方向上存在定向输运现象,相变产生的蒸汽会携带热量从高温区往低温区流动,从而抑制液冷板低温冷却水对加热表面温度分布的影响,提高了均温性能。

Abstract:

To improve the thermal uniformity of liquid cooling system for the battery thermal management, a three-dimensional CFD model for the coupled heat and mass transfer in the liquid cooling system was established, which was consisted of a grooved aluminum vapor chamber and a one-through flow liquid cooling plate. The numerical model was solved by VOF method and verified by experimental data. The results show that the thermal uniformity can be improved by the vapor chamber. The temperature difference of the heating surface can be kept within 2.72 K, which is related to the heat and mass transfer process of working medium in the vapor chamber. With the impact of the temperature rise of the coolant, there is a directional flow of vapor phase in the longitudinal direction inside the vapor chamber. The heat energy of the vapor phase can be transported from the high-temperature region to the low-temperature region. Therefore, the influence of cooling water with large temperature rise on the temperature distribution of surface can be suppressed, and the thermal uniformity can be improved.