Experimental Study on the Dynamics of a Thin Liquid Film under Shearing Force

doi:10.3901/JME.2017.24.070

Abstract

Abstract: The "scales-separation" phenomenon indicates that high heat-flux boiling and boiling crisis is dominated by micro-hydrodynamics of liquid microlayer on the heater surface. The techniques for liquid film measurement such as acoustic methods, nucleonic techniques, electrical methods, and optical methods are discussed in detail. Accordingly, a confocal optical sensor system is used to detect the dynamics of liquid film sheared by the co-flowing air from above in a horizontal aluminum channel. The impact of the gas shearing on film behaviors is analyzed and the integrity of liquid film is discussed in detail. The results indicate that the liquid film thickness decreases due to the entrainment and shows a linear or nonlinear variation under different flow conditions. Additionally, for a specific surface, the critical film thickness for an integral film is found to have no relation with the gas and liquid flow rates but the fluctuation of the liquid film increases with the increasing gas velocity.

Key words: entrainment, instability, micro-layer, two-phase flow

CLC Number:

O359

WANG Ke, YE Jing, GONG Shengjie, MA Weimin. Experimental Study on the Dynamics of a Thin Liquid Film under Shearing Force[J]. Journal of Mechanical Engineering, 2017, 53(24): 70-76.

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