具有梯度结构吸液芯的均热板传热特性

The Heat Transfer Characteristics of Vapor Chambers With Gradient Structured Wicks

均热板是电子器件散热方案中常见的传热元件,而吸液芯结构是影响均热板传热性能的重要因素。本文将吸液芯划分为核心热源区和工质回流区,使用40μm、75μm和110μm三种粒径的球形铜粉和非球形铜粉开发三种热源区和回流区具有不同毛细性能的梯度结构吸液芯,并以均热板热阻和蒸发侧平均温度为指标开展对应均热板的传热性能测试。实验结果显示,对于两种单粒形双粒径吸液芯,使用较大粒径铜粉烧结核心热源区能有效提高均热板传热性能,且高充液率时传热性能相对较好。而双粒形双粒径梯度结构吸液芯能更好地平衡毛细力和渗透率对工质回流的影响,对应均热板传热性能最好,在实验最高加热功率时均热板总热阻比其他两种单粒形均热板最大降低约91%,并且最佳充液率适中,表明采用双粒形双粒径吸液芯可大幅提高均热板传热性能。

Vapor chamber as a conductive element is widely used in the heat dissipation of electronic devices. The geometric structure of the wick is of great importance in affecting the heat transfer performance of vapor chamber. In this study, the wick was divided into the central heat part and the circumfluence part. The heat and circumfluence parts of the gradient wick with different capillary performances were built by the spherical and non-spherical copper powders with diameters of 40 μm,75 μm, and 110 μm. The experimental test of the heat transfer performance of the vapor chamber was carried out by measuring the mean temperature at the evaporator and the whole thermal resistance.For the structure gradient wick with single-shaped and double-sized copper powder, the larger the size of powder at central heat part was, the higher the heat transfer performance of vapor chamber was. The gradient wick with double-shaped and double-sized copper powder could balance the effects between capillary and permeability rate on the circumfluence of working fluid. Compared with the single-shaped and double-sized wick, the vapor chamber with double-shaped and double-sized wick performed the best heat transfer ability, and with the filling ratio of 90%, its maximum thermal resistance was decreased by 91% on the condition of the highest heat power. Therefore, the heat transfer performance of vapor chamber was substantially enhanced by using the wick with double shapes and sizes.