Abstract:A numerical analysis of heat transfer in the pressure-driven microchannel flows was carried out using the finite-control-volume based SIMPLEC algorithm. The surface potential andionic concentration distribution of dilute solutions in microchannels were investigated by numerically solving Poisson-Boltzmann equation.The induced electrical body force was considered in the firstly modified Navier-Stokes equation to describe the flow field. All these equations were coupled with energy equation through the temperature-dependent liquid dielectric constant ,viscosity, and thermal conductivity. By numerically solving these equations aforementioned simultaneously, effects of the channel size, and aspect ratio on the Nusselt number Nu and Poiseuille number Po were discussed in this paper,respectively.