微通道内电渗压力混合驱动幂律流体流动模拟

Simmulation of Mixed Electroosmotic and Pressure-Driven Flows of Power-Law Fluids in Microchannels

为了研究微通道内电渗压力混合驱动幂律流体的流动特性,建立了微通道内电渗压力混合驱动幂律流体的计算模型,其双电层电势、流体的流场分布分别由Poisson-Boltzmann(P-B)方程和Navier-Stokes(N-S)方程描述.讨论了无量纲Debye(德拜)参数K、壁面ζ*电势和幂律指数n对流体流动特性和Poiseuille数的影响.结果表明,当压力梯度与外加电场方向一致(Γ>0)时,剪切变稀流体的速度大于剪切变稠流体;压力梯度与外加电场方向相反(Γ<0)时,结果相反.Poiseuille数是无量纲Debye常数K、壁面ζ*电势和幂律指数n的增函数.

The pressure effects on electroosmotic flows of power-lawfluids in microchannels were investigated. The electric double layer（ ED L） potential was described with the Poisson-Boltzmann（ P-B） equation,and the flowfield distribution of the power-lawfluid was characterized with the Navier-Stokes（ N-S） equation. Numerical simulation was carried out to discuss the influences of the dimensionless D ebyeHuckel parameter,the wall Zeta potential and the flowbehavior index on the flowproperties and the Poiseuille number. The results reveal that,in the case of the same pressure gradient direction with the electric field direction,the velocity of a shear-thinning fluid is higher than that of a shear-thickening one,whereas the result will be opposite for a reverse pressure gradient direction. The Poiseuille number is an increasing function of the dimensionless D ebye-Huckel parameter,the Zeta potential and the flowbehavior index.