过冷沸腾气泡行为的实验研究

EXPERIMENTAL INVESTIGATION ON BUBBLE BEHAVIORS IN SUBCOOLED BOILING

本文采用拍摄速度为10000帧/秒的高速摄影仪对不锈钢箔表面的过冷沸腾现象进行了可视化实验研究。实验结果与用微液层模型理论预测的结果一致。高过冷度区域的沸腾换热机理主要是由气泡生长、消失过程中温度边界层的强制排除(所谓强制对流)引起的。气泡周期主要由等待时间构成,这在过冷度高的情况下尤为显著。对等热流密度换热面,微液层模型预测的气泡周期与实验值比较吻合。

Bubble behaviors of subcooled boiling have been investigated by visual experiments. Boiling bubbles at stainless foil are observed by a high-speed camera with speed of 10000 frame/s in the nucleate pool boiling of subcooled water. The experiments clarified that one cycle of the individual bubble experiences four stages, i.e., the initial growth with a semi-spherical shape, the final growth with a spherical segment geometry, the condensation process and the waiting time. The experimental data of bubble periods agree with the theoretical predictions by the microlayer model.