摘要
考虑蒸发冷却效应、气相物质扩散、气液两相传热及界面变形,采用任意拉格朗日-欧拉法数值模拟研究了接触角θ、蒸发数Ec、Ma数对0.65cSt,硅油液滴固定接触角模型蒸发及Marangoni对流的影响。发现:液滴无量纲体积V~*变化与接触角θ、Ma数有关,而与Ec数无关;且V^(*2/3)随时间线性减少。当θ<0.175 rad时,随着Ma数的升高,液滴内部依次出现热毛细涡流结构、单个BM涡流结构及多个BM涡流结构。当0.175 rad<θ<0.479 rad时,存在热毛细涡流结构或多个BM涡流结构或两种同时存在,而无单个BM涡流结构。当θ>0.479 rad时,仅存在热毛细涡流结构。当0.105 rad<θ<0.401 rad时,每两种涡流结构的分界Ma数均随θ增大而减少。当θ>0.401 rad时,热毛细涡流结构与多个BM涡流结构的分界Ma数随θ增大而增大。
Taking into account of evaporation cooling,mass diffusion,two-phase heat transfer and gas-liquid interface deformation,the evaporation of a droplet of 0.65 cSt silicone oil with constant contact angle on a heated substrate is numerically investigated using Arbitrary Lagrangian-Eulerian method.The effects of contact angle θ,evaporation number Ec and Marangoni number Ma on the evaporation and the Marangoni convection are analyzed.Numerical results find that the variation of volume V＊ is affected by θ and Ma but not by Ec,and the V（＊2/3） varies with t＊ linearly.With increasing Ma,the thermocapillary convection,single-vortex Benard-Marangoni convection（BM convection） and multiple-vortex BM convection appear in sequence for θ 〈0.175 rad.Thermocapillary convection or multiple-vortex BM convection or both of them occur for 0.175 rad〈 θ 〈0.479 rad but without single-vortex Benard-Marangoni convection.Only thermocapillary convection appears for θ 〉0.479 rad.The neutral Ma between two kinds of vortex convection decreases with increasing contact angle for 0.105 rad〈 θ 〈0.401 rad,while it increases for θ 〉0.401 rad.
出处
《工程热物理学报》
EI
CAS
CSCD
北大核心
2017年第4期792-799,共8页
Journal of Engineering Thermophysics
基金
国家自然科学基金项目(No.51676018)
关键词
液滴蒸发
两相传热
界面变形
Marangoni对流
evaporating droplet
two-phase heat transfer
interface deformation
Marangoni convection
