Mesoscale simulation of Marangoni convection about a vapor bubble in a liquid with temperature gradients under microgravity conditions

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• 作者：Chaoyang Zhang^a ; Ping Cheng^a ; ^{pingcheng@sjtu.edu.cn" class="auth_mail" title="E-mail the corresponding author} ; Jianguang Cao^b
• 关键词：Marangoni convection ; Vapor bubble ; Microgravity ; Lattice Boltzmann method
• 刊名：International Communications in Heat and Mass Transfer
• 出版年：2016
• 出版时间：November 2016
• 年：2016
• 卷：78
• 期：Complete
• 页码：295-303
• 全文大小：2598 K

文摘

Marangoni convection around a 2-D vapor bubble in a liquid, subjected to an imposed negative temperature gradient in the vertical direction under microgravity conditions, is simulated with a newly developed lattice Boltzmann liquid/vapor phase-change method. It is shown that a floating bubble, initially at the center of a confined space, moves gradually toward the hot wall under zero gravity condition because of Marangoni convection. With the increase of the Marangoni number, Marangoni convection along the liquid–vapor interface appears to be more and more significant. Under microgravity conditions, a sessile bubble attached on a hot bottom wall facing upward at low superheats, the high velocity region on the liquid/vapor interface moves from the triple-contact line region upward as the wettability of the solid surface changes from hydrophobic to hydrophilic. It is shown that the average Nusselt number of such a sessile vapor bubble under microgravity conditions is larger or smaller than those under zero gravity condition, depending on whether the Marangoni convection is in a direction parallel to or opposite to the direction of the gravity.