Ma Niya, Duan Zhipeng, Ma Hao, Su Liangbin, Liang Peng, Ning Xiaoru, He Boshu, Zhang Xin
School of Mechanical, Electronic and Control Engineering, Beijing Jiaotong University, Beijing 100044, China.
Beijing Key Laboratory of Powertrain for New Energy Vehicle, Beijing Jiaotong University, Beijing 100044, China.
Micromachines (Basel). 2018 Feb 16;9(2):87. doi: 10.3390/mi9020087.
Developing a three-dimensional laminar flow in the entrance region of rectangular microchannels has been investigated in this paper. When the hydrodynamic development length is the same magnitude as the microchannel length, entrance effects have to be taken into account, especially in relatively short ducts. Simultaneously, there are a variety of non-continuum or rarefaction effects, such as velocity slip and temperature jump. The available data in the literature appearing on this issue is quite limited, the available study is the semi-theoretical approximate model to predict pressure drop of developing slip flow in rectangular microchannels with different aspect ratios. In this paper, we apply the lattice Boltzmann equation method (LBE) to investigate the developing slip flow through a rectangular microchannel. The effects of the Reynolds number (1 < < 1000), channel aspect ratio (0 < < 1), and Knudsen number (0.001 < 0.1) on the dimensionless hydrodynamic entrance length, and the apparent friction factor, and Reynolds number product, are examined in detail. The numerical solution of LBM can recover excellent agreement with the available data in the literature, which proves its accuracy in capturing fundamental fluid characteristics in the slip-flow regime.
本文研究了在矩形微通道入口区域形成三维层流的问题。当流体动力学发展长度与微通道长度具有相同数量级时，必须考虑入口效应，尤其是在相对较短的管道中。同时，还存在各种非连续或稀薄效应，如速度滑移和温度跳跃。关于这个问题的文献中的可用数据相当有限，现有的研究是用于预测不同纵横比的矩形微通道中发展滑移流压降的半理论近似模型。在本文中，我们应用格子玻尔兹曼方程方法（LBE）来研究通过矩形微通道的发展滑移流。详细研究了雷诺数（1 < < 1000）、通道纵横比（0 < < 1）和克努森数（0.001 < 0.1）对无量纲流体动力学入口长度、表观摩擦系数和雷诺数乘积的影响。LBM的数值解与文献中的可用数据能够很好地吻合，这证明了其在捕捉滑移流区域基本流体特性方面的准确性。
