不同加热方式下环路热管蒸发器可视化研究

针对环路热管内部工质相变及流动换热问题，设计了环路热管蒸发器中心通道可视化实验平台，研究了不同加热方式对热管内工质状态和传热特性的影响。结果表明：加热方式直接影响热管10W启动过程，双面加热启动速度最快。相同热载荷时，不同加热方式下环路热管热阻及蒸发器中心通道内液面高度和成核情况存在差异。10W - 40W热载荷时，随着热载荷的增大，三种加热方式的传热热阻均在减小。40W-50W热载荷时，顶部加热方式下的热管性能出现恶化，底部加热传热性能出现停滞，仅双面加热性能稳定并有提高趋势。随着热负荷的增加，蒸发器中心通道内气液界面升高、气泡的产生变得更加剧烈，蒸发器通过吸液芯向储液器的漏热量增加，进而影响环路热管的性能。

Visualization of the evaporator of loop heat pipe under different heating methods

In order to elucidate the phase change and heat transfer process of working fluid in the loop heat pipe (LHP), a visual experi-mental platform for the central channel of the LHP evaporator was designed to study the influence of the flow and heat transfer characteristics of working fluid in the LHP under different heating modes. The results indicate that the start-up process of the LHP at 10W directly affected by the heating mode and and the double-sided heating starts the fastest. With the same heat load, the heat resistance of the LHP and the liquid height and nucleation in the central channel of the evaporator under different heat-ing modes are different. With the increase of the thermal load, the thermal resistance of the LHP under three heating modes de-creases as the thermal load increased at 10W - 40W. The LHP performance under the top heating mode deteriorates, the bottom heating heat transfer performance stagnates, and the double-sided heating performance is stable and has a trend of improvement improves at 40W - 50W. With the increase of the heat load, the liquid height in the central channel of the evaporator rises, the generation of bubbles become more intense, and the heat leakage from the evaporator to the reservoir through the wick increas-es, thus affecting the performance of the LHP.