Influence of Variable Properties on Electro-osmotic Flows Through Rectangular Microchannels

In this paper a numerical investigation of pure electro-osmotic and combined electro-osmotic/pressure driven flows with Joule heating is presented. The fluid is a real electrolyte, i.e., its density, dynamical viscosity, specific heat, thermal and electrical conductivity are functions of the local temperature and of the fluid composition. A threedimensional microchannel of square cross-section is considered and the solution is obtained by means of the commercial software ANSYS Fluent 6.3. H2 boundary conditions are applied at the wall. Attention is paid to both the dynamical and the thermal behavior. Results are shown for the dimensional velocity and temperature field, as well as for the non-dimensional Poiseuille and Nusselt number. Significant deviations from the case of ideal fluids can be observed, which suggest further investigations to correct the existing correlation for constant properties