毕业论文移动版

摘要如今，均温板在电子器件散热领域已经得到广泛应用。均温板是一种利用工质 的相变过程，通过对潜热的吸收与释放，达到高效传热目的的一件物品。同时它还 能把高热流密度（热点）的热量有效地均匀分散开，平面展开成一个相对较均匀的 温度场。因此，如何制作尺寸更小、更轻便、更薄，并同时拥有更大传热极限的均 温板，在电子器件散热领域具有无比重大的意义。本文分别对泡沫铜和沟槽式均温 板的制作过程进行了探索，并对其进行了性能测试。而后采用可视化的方法，探寻 泡沫铜均温板内部的运行过程。81250

首先建立了较为完整的均温板性能测试实验台以及可视化实验系统，在冷凝端 采用水冷方法作为冷却方式。对泡沫铜和沟槽式均温板的制程进行了详细探索：使 用了真空钎焊的方法来烧结泡沫铜的毛细芯，并对均温板的上、下底板封焊，使用 全电子充注系统进行充注。同时也对可视化实验中需要的泡沫铜和沟槽式均温板进 行了设计与加工。

通过系统的性能测试，能得出结论：沟槽式均温板的散热性能并不优于泡沫铜 均温板，处于不同热流密度下的轴向热阻与市售的均温板相当。在失效前，均温板 热阻可达到 0。2K/W。通过时间失效性测试后，并没有发现性能衰减现象。启动特性 方面，沟槽式均温板较泡沫铜均温板表现更好，启动时间大约为 3-5 分钟。

最后，借由高速摄影系统，对所设计的可视化均温板内部的运行情况进行了观 察。我们发现：充注率为 30%时，随着热流密度的增加，没有出现池沸腾现象，而出 现了薄液膜蒸发模式。在热流密度不断增加时，蒸发面附近的吸液芯发生了由中心 向外逐渐干涸的现象；充注率为 100%，且热流密度低于 11W/cm2 时，也未发现池沸腾 现象，也就是薄液膜蒸发模式；当热流密度继续增大时，可观察到孔隙内的液位全 部呈脉动涨落，此为典型的池沸腾现象。上述的结果表明：在均温板充注率较低并 且加热功率较小的情况下，蒸发面上发生的相变换热是薄液膜蒸发模式，而不是通 常人们认为的池沸腾模式；在达到一定充液率和一定的加热功率后，会出现池沸腾 现象。

毕业论文关键词：均温板；泡沫铜；池沸腾现象：可视化

Abstract Phase change heat transfer components such as heat pipe,vapor chamber  has been used widely in the field of electronic device cooling。 Using the phase transition process of working medium, through the absorption and release of latent heat, vapor chamber achieves the goal of highly-efficient heat transfer performance。 It can effectively solve the hot spots problem in high heat flux power device。How to make the smaller and thinner vapor chamber with higher heat transfer limit have important significance for electronic device cooling field。 The development of the vapor chamber is reviewed in detail。 On the basis of this, different forms of vapor chamber: Grooved and copper foam vapor chamber, are designed and produced The processing technology of vapor chamber is studied。The performance tests and the visualization experiment are also carried out。

Firstly, the performance testing platform is established for the vapor chamber。 The silver copper solder is applied to sinter both plates and filling tube of vapor chamber by vacuum brazing furnace。Using electronic filling system, water filling and  vacuum pumping process are successfully completed。After spot welding method, the vapor chamber is fabricated。 Further, the vapor chamber for the visualization are also designed and manufactured Through test, it is found that the overall performance of the foam copper wicks better than that groove wicks。The axial thermal resistance we manufactured are similar to the vapor chamber which was bought。 In the before failure, the thermal resistance of vapor chamber can be reach to 0。2K/W。It is found that there is no  attenuation  failure phenomenon through two tests in different time。From the tests, we can see the rise of temperature of the groove vapor chamber is faster than the foam copper  vapor chamber,and the startup time is about 3-5 mintute。 (责任编辑：qin)