电场作用下单气泡行为的可视化

Experimental visualization of single bubbles in an electric field

为进一步探索电场强化沸腾换热的机理,利用高速摄像机研究绝热条件下注入到静止变压器油中的氮气泡在电场作用下的行为,获得了在不同电场作用下气泡形态成长的实验图像,并分析了电场作用下气泡的长径比、脱离体积和脱离周期随电场的变化关系。实验研究表明:随着电场强度的增大,气泡的长径比变大,脱离体积变小,脱离周期变短。电场中气泡行为的改变主要取决于电场强度和电极距离。外电场作用促进了注入气泡从小孔的脱离。

Experiments with a single bubble were conducted to further understand the underlying electrohydrodynamic enhancement mechanisms during boiling. Nitrogen bubbles were injected into stagnant, isothermal transformer oil through an orifice. A hlgh-speed camera was used to record the bubble formation in various electric fields. The bubble aspect ratio, departure volume and departure period were measured for different electric field strengths. The experimental results show that with increasing electric field strength, the bubble aspect ratio increases while the departure volume and departure period decrease. The bubble behavior in the electric field strongly depends on the electric field strength and the electrode distance, and the applied electric fields promote bubble departure.