Simulation of microscale chemical separation processes using the lattice-boltzmann method

摘要

FLuid flow in the micron to hundred micron size range promises to be qualitatively different from fluid flow in large geometries and offers many opportunities for creating and expliting novel flow configurations that can be used in chemical reactors and separations processes. The most significant difference between flow in conventional macrosized systems and flow at micron length scales is the increase in the relative importance of surface forces, particularly surface tension, as the dimensions of the flow configuration shrink. Surface tension forces between the fluid and the walls and at the interface between immiscible fluids are ordinarily negligable on length scales of a centimeter or so but can dominate the behavior of liquid in a 100 micron channel. The ability to include these effects in simulations of flow in microscale devices is critically important to support the design and testing of micro-chemical components and systems, but conventional fluid dynamics simulations are incapable of modeling the multiphase systems anticipated in many microtechnology applications. A promising new method for simulating fluid flow that can easily be adapted to multiphase flows is the lattice Boltzmann algorithm [1, 2]. One major advantage of the lattice Boltzmann method over other fluid dynamics simulation techniques is the ability to incorprate surface interaction terms directly into the equations of motion [3, 4]. This makes it possible to simulate multiphase-multicomponent systems in a straightforward way, without the introduction of complicated front-tracking techniques.