Li Zhigang, Wang Hai
Department of Mechanical Engineering, University of Delaware, Newark, Delaware 19716, USA.
Phys Rev E Stat Nonlin Soft Matter Phys. 2003 Dec;68(6 Pt 1):061206. doi: 10.1103/PhysRevE.68.061206. Epub 2003 Dec 31.
The transport of small particles in the free-molecule regime is investigated on the basis of gas kinetic theory. Drag force formulations were derived in two limiting collision models-namely, specular and diffuse scattering-by considering the potential force of interactions between the particle and fluid molecules. A parametrized drag coefficient equation is proposed and accounts for the transition from specular to diffuse scattering as particle size exceeds a critical value. The resulting formulations are shown to be consistent with the Chapman-Enskog theory of molecular diffusion. In the limit of rigid-body interactions, these formulations can be simplified also to Epstein's solutions [P. S. Epstein, Phys. Rev. 23, 710 (1924)].
基于气体动力学理论，对自由分子流区域中小颗粒的输运进行了研究。通过考虑颗粒与流体分子间相互作用的势场力，在两个极限碰撞模型（即镜面反射和漫散射）中推导了阻力公式。提出了一个参数化的阻力系数方程，该方程考虑了随着颗粒尺寸超过临界值时从镜面反射散射到漫散射的转变。结果表明，所得公式与分子扩散的查普曼-恩斯科格理论一致。在刚体相互作用的极限情况下，这些公式也可以简化为爱泼斯坦的解[P. S. 爱泼斯坦，《物理评论》23, 710 (1924)]。
