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本文利用可视化手段实验研究矩形截面微通道(1 mm×0.5 mm)内发生流动沸腾时气泡的生长及受限现象。实验使用去离子水为工质,气泡受限过程由高速CCD相机观察并记录。研究发现,气泡高度方向通道壁面的存在对气泡在该方向的生长产生强烈的限制作用,气泡生长后期顶端气液界面在并未与限制壁面接触时其曲率便明显减小,壁面对气泡生长的限制作用通过其对气泡界面施加一个壁面限制力而体现.通过对比不同运行工况条件下的气泡受限现象,分析讨论了气泡受限过程中其界面形状变化规律及影响因素。
In this paper, the growth and the confinement of bubbles during flow boiling in a rectangular cross-section microchannel (1 mm × 0.5 mm) were experimentally investigated by means of visualization. Experiments using deionized water as the working fluid, the process of limiting the bubbles by high-speed CCD camera to observe and record. It is found that the presence of the wall in the direction of the bubble height strongly restricts the growth of the bubble in this direction. The curvature of the tip gas-liquid interface at the late stage of bubble growth is obviously reduced when it is not in contact with the restricted wall. The limiting effect is manifested by exerting a wall restraining force on the bubble interface.By comparing the restraining phenomenon of bubbles under different operating conditions, the changing regularity of the interface shape and the influencing factors during bubble restraining process are analyzed and discussed.