过冷核态池沸腾汽泡扫荡中表面张力作用分析

Analysis of Surface Tension in Bubble Sweeping During Subcooled Nucleate Pool Boiling

针对目前微加热表面汽泡动学研究结果存在分歧现象,对超纯水过冷核态池沸腾过程中微尺度铂金加热丝表面的射流和汽泡扫荡现象进行了数值模拟.结果表明:汽泡的合并和脱离现象可在等温条件下发生,即不考虑表面张力分布不均或热毛细力作用的影响;射流的诱因是热毛细力效应,这与以往的分析结果一致;汽泡扫荡是泡底液层不对称温度场和表面张力分布不均引起的横向热毛细作用的共同结果,模拟结果与相关实验观测吻合.

Bubble dynamics on thin heated wire is not well understood. In this investigation,bubble sweeping phenomenon during subcooled boiling on a platinum micro heating wire,submerged in ultrapure water,was numerically simulated. The results indicate that the bubble coalescence and detachment phenomena could happen isothermally,i. e.,the non-uniform distribution of surface tension or the thermocapillary effect could be neglected in these processes. The bubble-top liquid jet flow is majorly induced by the thermocapillary effect,which is in good agreement with previous analyses. It also shows that bubble sweeping is caused by both the asymmetric temperature distribution near the liquid layer at the bubble bottom and the horizontal thermocapillary effect, which is in good agreement with a corresponding experimental observation.