Grant: Discovery Grants Program - Individual

In many industrial and research processes there is an interaction between an electric field and flow of fluids or gases. Among others this happens in all applications involving small particles, for example in electrostatic precipitators used in environmental protection. A phenomenon called the electric corona discharge is typically generated to electrically charge the particles, so that electric forces can be used to control the particle's motion. The electric corona discharge is a complex physical process relying on avalanche ionization of the gas molecules, but it also results in motion of the ambient gas, called the secondary electrohydrodynamic flow, or ionic wind. This flow can be sometimes beneficial, but is often a nuisance disturbing the intended functioning of a device. In both cases numerical simulation can be helpful in garnering better understanding of these complex phenomena, and the design and optimization of electrostatic devices.   The proposed research program will first deal with the development of a new numerical algorithm and computer program, which can be used for simulation of the electric corona discharge. The algorithm will incorporate avalanche ionization, attachment and recombination, and all essential ionic reactions and species in pure gases and mixtures. An efficient and accurate corona model will be a prerequisite for the gas flow analysis. Another area where the fluid-electric field interaction plays an important role is microfluidics. Small amounts of fluid, either flowing continuously in a microchannel, or in the form of droplets, are handled in order to perform chemical microreactions. In the proposed research program, the dynamics of droplet deformation and transportation in digital microfluidics will be simulated numerically. Pumping of fluids in microfluidics can be achieved in many different ways and the most promising is based on the AC electroosmosis effect. Investigations of this effect published in the current literature are based on an extremely simplistic model. A new more complex model will be developed, which will take into account a more complete description of the process. Then a numerical algorithm will be created and the efficiency of fluid pumping will be investigated.