微通道内气体-近壁颗粒流动传热数值模拟研究

Numerical simulation of flow and heat transfer between gas and near-wall particle in a microchannel

中文关键词: 微尺度流动传热  速度滑移/温度跳跃  近壁颗粒  数值模拟

英文关键词: micro-scale flow and heat transfer  velocity slip/temperature jump  near wall particle  numerical simulation

中文摘要:

      数值模拟了微通道受限空间内气体-近壁颗粒流动与传热过程，所建模型考虑微尺度气体的可压缩与 变物性特征，且在通道和颗粒壁面采用速度滑移和温度跳跃边界条件以考虑滑移区气体动量/能量非连续效应。在此 基础上，计算分析了克努森数（Kn）和颗粒偏移比对颗粒表面拖曳力系数（CD）以及传热努塞尔数（Nu）的影响 规律。研究结果表明，受气体稀薄效应影响，颗粒表面拖曳力系数呈减小趋势，换热过程也相应削弱；随颗粒与壁 面距离减小，颗粒表面拖曳力系数相应减小，而颗粒与其周围气体的传热过程由于近壁效应呈增强趋势。

英文摘要:

      A numerical model considering the compressibility and variable properties of gas fluid was established to simulate the gas-near wall particle flow and heat transfer characteristics in the microchannel. The velocity slip and temperature jump boundary conditions were implemented at the channel wall and gas-particle interface in the numerical modeling. The influence of Knudsen number and particle offset ratio on the drag coefficient and Nusselt number were studied based on the numerical predictions. The results show that the gas rarefaction effect decreases drag coefficient on particle surface and weakens heat transfer process between gas and micro particle. Moreover, the drag coefficient decreases with the decreasing of particle offset ratio, however, the heat transfer between gas and micro particle is enhanced due to the nearwall effect.