中文摘要：

基于分子动力学理论的准平衡态界面处界面蒸发/冷凝因素,以及汽泡底部微液层传热因素建立综合传热传质相变模型,对窄通道内汽泡过冷流动沸腾条件下的生长情况进行模拟。相变模型体现了汽泡底部微液层蒸发、近壁过热液体传热、汽泡顶部主流冷凝等多方面机制对汽泡生长的影响。模拟结果体现了汽泡底部微液层厚度的变化情况,与实验结果相吻合;微液层蒸发机制在汽泡生长初期对汽泡生长有较大影响,流道壁面效应对汽泡生长有显著影响。

英文摘要：

A single bubble growing model is established under subcooled flow boiling conditions in vertical rectangular narrow channel to numerically investigate the bubble growth. The model combines interface evaporation/condensation based on molecular dynamics and microlayer evaporation. The phase change model shows the multiple influences of micolayer evaporation under the bubble, superheated liquid near the heating wall, and subcooled mainstream. Numerical simulations results coincide with the experimental results well. The results reveal that the microlayer evaporation accelerates the bubble growth at the beginning, and the mainstream condensation keeps its size after the growing period. Details of bubble shape evolution and changes of microlayer thickness during the growth of the bubble are gained. It is found that the wall effect of narrow channel has an obvious effect on the bubble growing.