Analysis of flow characteristics through micro and nano channels with adsorbates.

分析通过带有吸附物的微纳米通道的流动特性。

基本信息

批准号：
15560144
负责人：
YAMAMOTO Kyoji
金额：
$ 1.73万
依托单位：
OKAYAMA UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2003
资助国家：
日本
起止时间：
2003 至 2004
项目状态：
已结题

项目摘要

The characteristics of the reflected gas molecules were theoretically investigated when other gas molecules are physically adsorbed on the wall surface of micro and nano channels. The accommodation of gas molecules to the wall, and the stress and energy flux on the wall are calculated for various surface characters. We took the platinum surface as a solid wall, and nitrogen and argon molecules as gas molecules. The Couette flow and the thermal problem between two parallel walls whose temperatures are different each other are considered. The wall temperature considered in the present analysis is 300K. We apply the DSMC method for the motion of gas molecules between two walls and the molecular dynamics methods for the interaction between gas molecule and the wall surface. Two cases of wall surface structure are considered, that is, a smooth surface and a grooved surface of molecular scale. The wall surfaces with adsorbed gas molecules are also considered.We obtained the following results : the accommodation coefficients are different for different groove direction. These values on the adsorbed wall surface are much higher than those on the clean surface. The values calculated are in good agreement with the experimental values. We proposed a new boundary condition of the velocity distribution function for the reflected molecules at the wall surface. Namely, the distributions are separated in each velocity direction, and it has the Maxwell-type distribution with accommodation coefficient calculated in the present study. It was found that the proposed boundary condition well describes the flow behavior.Using the boundary conditions proposed, we analyzed the micro-channel flow of gas mixtures, and clarified the effect of the adsorbates on the flux through the channel

当其他气体分子物理吸附在微型和纳米通道的壁表面上时，理论上研究了反射气体分子的特征。对于各种表面特征，计算气体分子到壁上的容纳和壁上的应力和能量通量。我们将铂表面作为固体壁，氮和氩分子作为气体分子。考虑了两个平行壁之间的气流和温度不同的平行壁之间的热问题。目前分析中考虑的壁温为300K。我们将DSMC方法应用于两个壁之间的气体分子和分子动力学方法之间的运动，以进行气体分子与壁表面之间的相互作用。考虑了两种壁表面结构的情况，即光滑的表面和分子尺度的凹槽表面。还考虑了带有吸附气体分子的壁表面。我们获得了以下结果：对于不同的凹槽方向，适应系数不同。吸附的壁表面上的这些值远高于清洁表面上的值。计算出的值与实验值非常吻合。我们提出了在壁表面反射分子的速度分布函数的新边界条件。也就是说，分布在每个速度方向上分开，并且具有麦克斯韦型分布，并在本研究中计算出适应系数。发现所提出的边界条件很好地描述了流动行为。使用提出的边界条件，我们分析了气体混合物的微通道流，并阐明了吸附物对通道通道的影响