An investigation on dynamic thickness of a boiling liquid film

作者：Gong, Shengjie^*; Ma, Weimin; Wang, Chi; Mei, Yong; Gu, Hanyang

来源：International Journal of Heat and Mass Transfer, 2015, 90: 636-644.

DOI：10.1016/j.ijheatmasstransfer.2015.07.011

• Boiling
• Liquid film dynamics
• Film thickness measurement
• Macrolayer
• Microlayer
• CHF

Motivated by understanding the micro-hydrodynamics of boiling heat transfer and the mechanism of critical heat flux (CHF) occurrence, the present study is to investigate the boiling phenomenon in a liquid film whose dynamic thickness is recorded by a confocal optical sensor with the measurement accuracy of micrometres, while the bubble dynamics of the boiling in the film is visualized by a high-speed photography. This paper is focused on a statistical analysis of the measured thickness signals for the boiling condition ranging from low heat flux to high heat flux (near or at CHF). The dynamic thickness of liquid film appears oscillating with peak values, resulting from the liquid film movements due to nucleation of bubble(s) and its growth and rupture. The statistical analysis in a certain period indicates there emerge three distinct liquid film thickness ranges: 0-50 mu m, 50-500 inn and 500-2500 mu m, seemingly corresponding to the microlayer, macrolayer and bulk layer. With increasing heat flux to a specific extent, the bulk layer disappears, and then the macrolayer gradually decreases to similar to 105 mu m, beyond which the liquid film may lose its integrity and CHF occurs at 1.563 MW/m(2).

• 出版日期2015-11
• 单位上海交通大学