加热铂丝上运动汽泡产生的射流

JET FLOWS FROM MOVING BUBBLES ON MICROWIRES

目前很多水的核态沸腾都观察到了汽泡顶部射流的现象。本文分析了沿细丝运动的汽泡顶部产生射流的物理机理,并通过对汽泡和加热细丝周围温度场和速度场的数值求解来进行分析。结果显示:由汽泡前后表面的温度梯度引起的热射流很可能是流动的最主要原因。热射流能够推动汽泡前进。对比和试验的观测指出,不凝气体或者其他可能的机理将限制汽泡界面处的凝结换热,从而增大表面温度梯度,增强热射流。

This paper analyzes the physical mechanisms causing jet flows from the tops of bubbles moving along microwires. The flows were analyzed by numerically solving the governing equations for the velocity and temperature distributions around the bubble and the heated wire as the bubble moves along the wire. The results show that the flow is driven by the temperature difference from the front to the back of the bubble resulting from the bubble motion. The resulting Marangoni flow would provide thrust to push the bubble forward. Comparisons with experimental observations suggest that the condensation heat transfer at the bubble interface must be restricted by noncondensible gases that increase the surface temperature gradient and the resulting Marangoni flow.