多液滴槽道湍流减阻的直接数值模拟研究  

Direct numerical simulation of drag reduction in turbulent channel flow with multiple droplets

作　　者：高畅 潘定一 Chang Gao;Ding-yi Pan(School of Aeronautics and Astronautics,State Key Laboratory of Fluid Power&Mechatronic Systems,Zhejiang University,Hangzhou 310027,China)

机构地区：[1]浙江大学,航空航天学院,流体动力与机电系统国家重点实验室,杭州310027

出　　处：《水动力学研究与进展（A辑）》2022年第4期547-554,共8页Chinese Journal of Hydrodynamics

基　　金：国家自然科学基金(91852205和11972322)。

摘　　要：该文以含液滴的槽道湍流为研究对象,采用格子玻尔兹曼方法耦合相场模型对其进行直接数值模拟研究。首先针对传统相场模型在模拟较高雷诺数两相流系统的缺陷,引入高阶精度WENO格式离散Cahn-Hilliard方程中对流项以改善液滴相的质量守恒。其次,基于改进的数值模拟方法,重点考察了液滴体积分数(1.6%-3.1%)对槽道湍流减阻效应的影响。模拟结果发现:通过加入可变形的液滴可使槽道湍流平均流速增加,从而达到减阻的效果。液滴体积分数越大,减阻效应越明显,且液滴总表面积会随着体积分数的增加而减小更多,表明高体积分数时液滴合并现象更明显。进一步考察了韦伯数和液滴初始尺寸对槽道湍流减阻的影响,在研究的参数范围内,韦伯数越大,减阻效应越明显,而液滴初始尺寸对减阻影响较小。Droplet-laden turbulent channel flow is simulated based on Lattice Boltzmann method coupled with phase field model.Firstly,the high-order WENO scheme is applied to the discretization of convection terms in Cahn-Hilliard equations and the mass conservation of droplet phase is improved accordingly.Secondly,drag reduction of droplet-laden turbulent channel flow is investigated by the improved numerical methods and special emphasis is put on the effects of droplet volume fraction(1.6%~3.1%).The simulation results show that the wall drag is reduced by the deformable droplets,and the larger volume fraction of droplets the larger average streamwise velocity of the channel.Meanwhile the total surface area of droplets decreased fast at relatively high volume fraction indicating the coalescence of droplets is enhanced.Thirdly,the effects of Weber number and initial droplet size are investigated as well.In the parameter ranges of present study,the wall drag decreases with the increase of Weber number,whereas the effect of initial droplet size is negligible.

关 键 词：液滴 槽道湍流 格子玻尔兹曼方法 相场模型 减阻 

分 类 号：O352[理学—流体力学]