The Simulation Of Electroviscous Effects And The Mixed Driven Flow Of Power-law Fluids In Microchannel

Microfluidic Chip(MFC)is a novel kind of micro total analytical system. It has been widely used for its advantages of small size, high precision and easy to operation, etc. This paper aims to study the fluid flow characteristics of the power- law fluid according to the methods of theoretical analysis and numerical simulation. The main research work and achievement are as follows:Based on the PNP model and combined with the current density balance condition, this paper analysis the influence of the electroviscous effects in purely pressure driven flow which is the electroosmotic flow of power- law fluids in a slit microchannel. Revealing the characteristic of the power- law fluid in the pressure driven microchannel. The result shows that when considering the electroviscous effects in the microchannel the velocity of the fluid flow would be reduced and the fluid flow would generated a streaming potential. The strength of the streaming electric field would reduce with the increase of flow behavior index. Contrary to the electroosmotic flow the velocity of the pressure driven flow increased with the increasing concentration of the fluid. The fluid concentration has a great influence on the apparent viscosity. The low concentration fluid would cause more variation of the fluid apparent viscosity.A numerical simulation has toke on the electroviscous effects of the power law fluid in purely pressure driven microchannel, which is an inerratic changed microchannel. Analysis the influence of the size of the microchannel on the fluid velocity and the streaming potential, which compared with the straight microchannel. It is reveals that the velocity of the inerratic changed microchannel is less than the straight microchannel and that the reduce of the velocity which caused by the electroviscous effects also less than the straight microchannel?But the streaming potential in the inerratic changed microchannel is more than the straight microchannel. The results also shows that the shape of the microchannel have significant influence on the property of the fluid flow.Based on the finite element method(FEM) and the dimensionless mathematical model, this paper aims to study the fluid property of the electroosmotic flow o f power-law fluid in the microchannel with the presence of pressure gradient. The result shows that the dimensionless parameters have a great influence on the fluid viscosity. Poiseuille number is a increasing function of the dimensionless Debye parameter and the zeta potential. The growth trend increased with the flow behavior index. The viscous dissipation parameter and the joule heating parameter have a great influence on the temperature profile. It is seen that the temperature difference across the channel rises with the increasing flow behavior index. The dimensionless temperature increasing with the rising zeta potential and the viscous dissipation parameter. The zeta petechial can significantly affect the thermal behavior especially When the dimensionless Debye parameter at a lower value the Nusselt number increased with the rising zeta potential.