Flow Modeling through an Electro-statically Charged Monolith Filter

Abstract

GIRISAN, VIVEK. Flow Modeling through an Electro-statically Charged Nano-Particle Filter. (Under the direction of Dr. Andrey Kuznetsov).

The modeling of flow thorough regular sized channels is a relatively easy task, but when the channel size reduces to the order of micro and nanometers the physics of the particle motion changes. A lot of other factors have to be taken into consideration, such as Brownian Motion and Vander-Waal forces. At such a small scale it is hard to determine which forces are more dominant, i.e. we do not know whether the drag force is greater than the electrostatic force or the electrostatic force is greater than the Brownian force. The aim of this thesis is to solve some of these problems and try to create a better understanding of the forces in question. The application of such a filter is in capturing nano size particles such as viruses. Since these particles are so small it is hard to capture them by physical means. We have to devise new techniques to capture these particles. There are several challenges to this problem, since we are dealing with such small scales it is hard to perform experiments to get data. Instead we have to spend a lot of time getting analytic solutions so that when we sure of our results we can carry out experiments. The fabrication of such a filter is an extremely complicated process. In fact even if we have the filter it is hard to mount it in an experimental setup without damaging it. Hence to save time and money we use theory and simulations to determine how the flow pattern will be and how many particles can or will be captured. A large part of these simulations was carried out using a Finite element package called COMSOL Multi-Physics. This package is a great multi-physics tool as is allows seamless integration of various physics, in this case it is mainly Navier Stokes Equations and Electrostatic Equations. Brownian motion is extremely hard to model and it was modeled separately using Matlab since Comsol does not have built in capabilities to handle Brownian motion.