This paper presents fundamental research on the hydrodynamics and heat transfer surrounding a single elongated bubble during flow boiling in a circular microchannel. A continuum surface force (CSF) model based on the volume of fluid (VOF) method is combined with the thermocapillary force to explore the effects of thermocapillarity for flow boiling in microchannels. To validate the self-defined codes, a two-phase thermocapillary-driven flow and a Taylor bubble growing in a capillary tube are studied. Results of both test cases show good convergence and agreement with data from the earlier literature. The bubble motion and the local heat transfer coefficient (HTC) on the heated wall with respect to time are discussed. It is found that for large Marangoni number (case 3), variation of surface tension has affected the bubble shape and temperature profile. The thermocapillary effect induces convection in a thin liquid film region, which augments the HTCs at specified positions. The numerical investigation also shows that the average HTC increased by 6.7% in case 3 when compared with case 1. Thus, it is very important to study further the effects of themocapillarity and the Marangoni effect on bubble growth in microchannels.
Simulation of Single Bubble Evaporation in a Microchannel in Zero Gravity With Thermocapillary Effect
Hangzhou 310027, China;
Collaborative Innovation Center of Advanced
Hangzhou 310027, China
Jinan 250061, China
University of Illinois at Chicago,
Chicago, IL 60607
Contributed by the Heat Transfer Division of ASME for publication in the JOURNAL OF HEAT TRANSFER. Manuscript received November 3, 2017; final manuscript received April 27, 2018; published online July 23, 2018. Assoc. Editor: Guihua Tang.
Li, W., Luo, Y., Zhang, J., and Minkowycz, W. J. (July 23, 2018). "Simulation of Single Bubble Evaporation in a Microchannel in Zero Gravity With Thermocapillary Effect." ASME. J. Heat Transfer. November 2018; 140(11): 112403. https://doi.org/10.1115/1.4040147
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