剪切流中液滴变形及破裂的数值模拟  

Numerical simulation of droplet deformation and breakup in shear flow

作　　者：龚旺 杨帆[1] GONG Wang;YANG Fan(School of Energy and Power Engineering/Shanghai Key Laboratory of Multiphase Flow and Heat Transfer in Power Engineering,University of Shanghai for Science and Technology,Shanghai 200093,China)

机构地区：[1]上海理工大学能源与动力工程学院/上海市动力工程多相流动与传热重点实验室,上海200093

出　　处：《能源研究与信息》2024年第1期51-60,共10页Energy Research and Information

摘　　要：基于格子Boltzmann颜色梯度模型,针对二维剪切流场中液滴的变形及破裂进行了数值模拟,研究了剪切流动中毛细数Ca、雷诺数Re和流体黏度比λ对液滴变形的影响,并在Re−Ca相图中区分了三种不同的液滴变形或破裂方式。为了进一步掌握界面对液滴内部不同位置流体的作用,引入示踪粒子并分析其在液滴内的运动规律。结果表明:随着Ca的增大,液滴的变形效果和偏转角度更明显,示踪粒子运动受到的影响较大;随着Re的增加,液滴的变形程度加大,但偏转角度受其影响较弱,示踪粒子运动受其影响显著;在低黏度比(λ<0.8)时,液滴会经历大幅度变形过程,当黏度比继续增大,其变形参数反而会减小;示踪粒子离初始圆心距离越近,运动路程越大,受到的剪切作用越大,且其在剪切作用下离界面越来越近,并最终达到稳定状态。Based on lattice Boltzmann color gradient model,numerical simulation was carried out for the deformation and breakup of droplets in two-dimensional shear flow.Effect of capillary number Ca,Reynolds number Re and viscosity ratioλof different fluids on droplet deformation in shear flow was investigated.Three different deformation or breakup ways of droplets were distinguished in the phase diagram of Re-Ca.In addition,to understand the effect of interface on the fluid inside the droplet,tracer particles were introduced,and their motion patterns in the droplets were analyzed.Results show that the increase of Ca number resulted in enhanced deformation effect and weaker deflection angle of droplets,which affected the motion of tracer particles greatly.With the increase of Re number,the droplets deformation became strong,while weak deflection angle was observed.These phenomena affected the motion of tracer particles significantly.When the viscosity ratio was low(λ<0.8),the droplets underwent a large deformation process.When the viscosity ratio continued to increase,the deformation parameter decreased.The closer the tracer particle to the initial center of circle,the longer the movement distance,which caused greater shearing effect on tracer particles.They got closer to the interface and stabilized ultimately.

关 键 词：颜色梯度模型 剪切流动 液滴变形 液滴破裂 示踪粒子 

分 类 号：O35[理学—流体力学]