| Summary: | 碩士 === 國立中央大學 === 機械工程研究所 === 93 === The electroosmotic (EO) pump has been widely used in driving and controlling microfluidics in the biomedical and biochemical applications, and it is being used for cooling liquid transportation in the micro cooler in electronics industry recently. The physical models of present numerical study are based on 1) the Poisson-Boltzmann equation for electrical double layer (EDL) potential, 2) the Laplace equation for the externally applied electrostatic field, and 3) the Navier-Stokes equation modified to account for the electro-kinetic body force and porous media effect. This study numerically analyzed various flow characteristics of porous media within the EO pump.
We first validated the EO flow in a micro circular capillary tube with theory, and then developed a model for embedded micro particles into a circular capillary tube to mimic the porous media channels in a realistic EO pump. We have thoroughly investigated the effect of the ratio of zeta potential at wall to zeta potential of particles, which is a dominant factor for affecting the characteristics EO flow within the porous media. Numerical solution agrees with analytical solutions and it also compare with available experiment data, this modified model can effectively correct overestimated values of flowrate and back pressure in previous analytical model. We found many factors affect the EO flow within the porous media; these factors are the ion concentration, the pore size of porous media channel, the applied electrical field and the zeta potential.
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