Electroosmotic And Pressure Driven Measurement And Simulations Of Power-law Fluids

Microfluidics technology refers to detect,operate and control complex fluids at a micro scale.It is a new interdisciplinary subject developed in multiple disciplines microelectronics,micro mechanical,nanotechnology,bio engineering,instrument science and technology.etc.In this paper,the methods of theoretical analysis,numerical simulation and experimental research are used to study the characteristics of non-Newtonian power-law fluidics driven by electroosmotic and pressure.The main contents and results are as follows:The advantages and disadvantages of various materials used in the fabrication of micro channel chip are compared in this paper,and introduced the characteristics of PMMA and PDMS of polymer materials and the fabrication technology of micro channel.designed and manufactured of microchannel for experiment.This paper also introduced the experimental principle and experimental system of electro osmotic driving and pressure driving.And the experimental data acquisition program was designed based on the NI PCI-6014 acquisition card and LabVIEW programming software.The feasibility of the experimental system is verified by comparing the experimental results with the simulation data.The rheological behavior of sodium carboxymethyl cellulose(CMC)solution was introduced and the effects of different concentrations and different cations on the rheological behavior of the solution were analyzed in paper.Experiments were carried out to study electroosmotic flow and pressure flow characteristics under different channel sizes and solutions.The experimental result indicated that adding Na+ and Ca2+ into the solution can change the rheological behavior of the fluid,respectively.And the viscosity of the non-Newtonian fluid is to larger to show good driving efficiency.Furthermore,due to the micro scale effects and electroviscous effect,it is observed that fluid flow has a nonlinear relationship with the pressure difference,and adding cationic solution can change the power-law fluid viscosity and enhanced electroviscous effect.The flow and heat transfer of power-law fluid driven by electro osmotic pressure in a three-dimensional rectangular microchannel are studied by numerical simulation,and the effects of flow parameters on the temperature distribution and heat transfer in microchannel are analyzed in detail.The results reveal that increasing the power-law exponent n and the zeta potential increases the ?,and the increase of the dynamic parameter K decreases the ?.Moreover,increasing the channel aspect ratio can enhance heat transfer performance,but the Joule heat coefficient S and the dynamic parameter K will be a decreasing function of the Nunumber.