A Lattice Boltzmann Model for Non-Equilibrium Flows in Micro/Nano-systems

近十年来，微纳机电系统和微全分析系统技术得到了迅速发展。这些小型化的系统有可能显著提高化学、生物和临床分析的产率，并将显著减少处理时间和试剂消耗。然而，在预测依赖于操纵气流的设备的性能方面存在一个主要问题。当气体分子的平均自由程与这些微/纳米体系的特征尺寸相当时，Navier-Stokes方程所依赖的热力学准平衡假设是不合适的。本研究旨在探索能否建立一种介观格子Boltzmann方程(LBE)方法来预测具有0.1-1000微米特征长度尺度的系统中的非平衡气体动力学，在下文中我们将其称为微/纳米系统。我们将根据已发表的各种流动形态下的观测结果和中银爱德华兹提供的实验数据，对我们的LBE模型进行测试。如果成功，这项研究的结果将有助于开发一种有效的模拟能力，在工业相关的微/纳米系统几何形状的气体流动。

The technology of Micro/Nano-Electro-Mechanical Systems and Micro-Total-Analysis Systems has developed rapidly in the last decade. These miniaturised systems offer the potential to increase yields significantly in chemical, biological and clinical analyses and will lead to significant reductions in process time and reagent consumption. However, there is a major problem in predicting the performance of devices that depend on manipulating gas flows. The thermodynamic quasi-equilibrium hypothesis, on which the Navier-Stokes equations depend, is inappropriate when the mean free path of the gas molecules is comparable to the characteristic dimension of these micro/nano-systems. This research aims to explore whether a mesoscopic lattice Boltzmann equation (LBE) methodology can be established that can predictively model the non-equilibrium gas dynamics in a system with a characteristic length scale between 0.1-1000 microns, which we refer to as a micro/nano-system in the following sections. We will test our LBE model against published observations in a variety of flow configurations and with experimental data provided by BOC Edwards. If successful, the outcomes of this research would contribute to the development of an efficient simulation capability for gas flows in industrially-relevant micro/nano-system geometries.