摘要
以氧化铝纳米流体液滴为研究对象,本文建立了基于任意拉格朗日-欧拉(ALE)法的液滴蒸发瞬态模型,对液滴蒸发过程中蒸汽浓度、纳米颗粒浓度、温度等进行多物理场耦合,并考虑了Marangoni流对液滴蒸发的影响,同时研究还结合蒸发实验可视化结果,分析了氧化铝纳米流体液滴的瞬态蒸发速率随时间的演化规律,讨论了颗粒体积分数和基板温度对蒸发模式的影响。结果表明,在液滴蒸发过程开始时,纳米流体液滴保持定接触半径蒸发模式,气液界面面积逐渐减小,瞬态蒸发速率也呈逐渐减小的趋势;当颗粒体积分数增大至26%时,瞬态蒸发速率曲线达到驻点;蒸发接近完全时,由于Marangoni流影响了内部流场、强化了内部传热,且液滴在已沉积在基板上的颗粒表面形成液膜,瞬态蒸发速率迅速增大。
The applications of nanofluid droplet evaporation play an important role in inkjet printing,chip manufacturing and medical diagnosis.An arbitrary Lagrangian-Euler(ALE)method was applied to transiently simulate the evaporation period of alumina nanofluid droplets.The physical fields of vapor concentration,nanoparticle concentration,temperature gradient and flow direction during the evaporation process were coupled and the effect of Marangoni flow inside the droplets was taken into consideration.Meanwhile,according to the visualization images of evaporation experiments,the evolution behavior of the transient evaporation rates of nanofluid droplets and the effects of particle concentration along with substrate temperature on the evaporation modes were analyzed and discussed,respectively.The results demonstrated that at the beginning of the evaporation process,the nanofluid droplets remained in the evaporation mode with constant contact radius,and the transient evaporation rates decreased gradually with the decrease of the gas-liquid interface area.In the middle stage of evaporation process,when the particle concentration increased to 26%,the transient evaporation rate curve reached the stationary point.Due to the influence of Marangoni flow on the internal flow field of the droplets,the internal heat transfer of droplets was enhanced as the evaporation process reached to the end.Moreover,the droplets formed a liquid film on the surface of the particles which had been deposited on the substrate,the transient evaporation rates of droplets raised rapidly therefore.
作者
李钰璨
胡定华
刘锦辉
LI Yucan;HU Dinghua;LIU Jinhui(MIIT Key Laboratory of Thermal Control of Electronic Equipment,Nanjing University of Science and Technology,Nanjing 210094,Jiangsu,China)
出处
《化工进展》
EI
CAS
CSCD
北大核心
2022年第7期3493-3501,共9页
Chemical Industry and Engineering Progress
基金
国家自然科学基金青年基金(51706102)。
关键词
蒸发
数值模拟
传热
纳米流体
液滴
evaporation
numerical simulation
heat transfer
nanofluid
droplets
