双弥散多孔介质平板通道内纳米流体流动特征

Flow Characteristics of Nanofluid in a Parallel-Plate Channel Occupied by a Bidisperse Porous Medium

基于双速度Brinkman-Darcy扩展动量模型,分析Cu/H2O纳米流体在双弥散多孔介质平板通道内的流动特征.采用正常模式降阶法推得双弥散多孔介质裂纹相(f相)和多孔相(p相)的速度分布解析解.参数分析表明,两相中纳米流体的速度随着固体颗粒体积分数的增加而降低;动量传递系数增加,两相速度呈相反趋势变化,且速度差变小;达西(Darcy)数增大,两相速度增大且速度差变大;当仅p相Darcy数增大时,导致双弥散效应增强,两相速度亦同时增大,但两相速度差变小;随着纳米流体体积分数增加,流动阻力增大.

Based on the two-velocity Brinkman-extended Darcy momentum model,the characteristics of Cu/H 2O nanofluids in a parallel-plate channel filled with a bidisperse porous medium(BDPM)was analyzed.The analytica1 solutions for BDPM fracture(f)and porous(p)phase velocity distributions were derived by the norma1 mode reduction method.The parametric study indicates that an increase in the nanoparticle volume fraction leads to a reduction in the fluid velocities for both phases.As the momentum transfer coefficient increases,the change of f-phase velocity exhibits an opposite trend and the velocity difference between the two phases becomes smaller.With increasing Darcy numbers,the velocities of two phases as well as their difference increase.For the case of increasing p-phase Darcy number only and consequently enhancing the bidispersion effects,the velocities for both phases increase while their difference becomes smaller.As the volume fraction of nanofluid increases,the flow resistance increases.