微通道内Cu-H2O纳米流体强制对流特性的数值模拟研究

Numerical Simulation of Flow and Heat Transfer Characteristics of Cu-H2O Nanofluids in Microchannel

采用格子玻尔兹曼方法(Lattice Boltzmann Method,LBM)研究了Cu-H2O纳米流体在二维微通道内强制对流流动与传热特征,分析了微通道内Cu纳米颗粒的体积分数φ、雷诺数Re、相对粗糙度ε等因素对流体流动与传热的影响。结果表明:在光滑壁面条件下,随着入口处Re数的增加,壁面处Nuave会随着变大,同时随着纳米流体体积分数φ的增加,壁面处Nuave也会增加;与光滑壁面相比,在粗糙壁面条件下,随着入口处Re数和纳米流体体积分数φ的增加,壁面处Nuave也随之增大,但Nuave数的增大程度要比光滑壁面条件下小,且随着壁面相对粗糙度ε的增大,壁面处Nuave随之减小。

The forced convection and the heat transfer feature of Cu-H2O nanofluids in two dimensional channel is studied by Lattice Boltzmann method(LBM), and the effects of volume fraction(φ), relative roughness(ε), Reynolds number(Re) of the Cu nanoparticle in microchannel on the fluid flow and heat transfer are analyzed. Results show that when the wall surface is smooth, with the increase of Re at the entrance, the Nuave at the wall increases, and that with the increase of volume fraction φ, the Nuave also increases;when the wall surface is tough, with the increase of Re at the entrance and volume fraction φ, the Nuave at the wall increases, but the increment is less than that when the wall surface is smooth. Besides, with the increase of relative roughness ε, the Nuave decreases.