A single domain formulation on conjugate heat transfer in parallel plate microchannel with electrical double layer

• Increasing of zeta potential decreases the heat transfer rate in the microchannel.
• An analytical/numerical solution method is proposed for conjugate heat transfer.
• Nusselt number has a non-monotonic behavior as the wall thickness varies.

In this study, the conjugate conduction-convection heat transfer in the thermally developing region of a parallel plate microchannel with the constant heat flux at the walls is investigated. The flow is forced to move by applying the pressure difference and is assumed to be fully developed. Moreover, the effects of electrical double layer (EDL) with low zeta potential on the fluid flow and on the temperature field are taken into account. To do so, an analytical/numerical method is proposed to solve the energy equation in a single domain formulation. The energy equation is split and a series solution based on the variational calculus is employed to determine the temperature field. The effects of various parameters such as Peclet number, non-dimensional wall thickness, thermal conductivity ratio, and the zeta potential are studied in details. The obtained results show that the increasing of zeta potential decreases the heat transfer rate. Moreover, the Nusselt number has a non-monotonic behavior when the wall thickness varies.