| dc.description.abstract | The electroosmotic pump (EOP) has been widely used in driving and controlling microfluidics in the biochemical applications, and it is being used for liquid transportation in the electronics cooling solution recently. Thus, the temperature variation and the performance of the EOP for fluid transporting are very important. This study presents a transient numerical analysis of the electroosmotic flow in micro tubes and in porous media, combining analytical solutions and the validation of experimental data, to investigate velocity, pressure and the temperature characteristics of EOP. The mathematical model include the Poisson-Boltzmann equations for electric potential, the Laplace equation for external applied electric field, the modified Navier-Stokes equations for velocity field, and the energy equations for temperature field.
Numerical results reveal that several factors affect the temperature characteristics of the EOP including: the size of EOP, the strength of applied electric field, the concentration of fluid and the cooling condition surrounding the tube. When the Joule heating effect is severe, the auto-thermal phenomenon causes large temperature rise and variation of the fluid viscosity and the dielectric constant, results in modifying the performance of EOP. Although the temperature increases help to enhance the operation of EOP; however, there is an upper limit of operating temperature for most applications of EOP. Therefore, selecting proper conditions in designing EOP is very important. Besides, it is also found that the wall effect from both the geometry and the electrokinetic need to be considered in the simulation of electroosmotic porous flow, otherwise, calculation results will not accurate. | en_US |