Electro-magnetohydrodynamic membrane pumping in a vertical microchannel: coupled thermal and buoyancy effects

Abstract This work presents a micro-pumping principle that leverages the synergistic behavior of electro-magnetohydrodynamics (EMHD) and active thermal control to enhance transport processes at the microscale. The model developed is an analysis of a Newtonian fluid in a finite vertical microchannel, with pumping triggered by a pressure gradient induced by a membrane. Analytical solutions of the governing mass, momentum, and energy equations for low Reynolds number flow are obtained using the optimal homotopy analysis method (OHAM), and the results are supported by finite difference simulations. The parametric analysis shows that distinct roles for the Hartmann number, Grashof number, electric field strength, heat source parameter, and electric double layer (EDL) characteristics on system performance exist. The results reveal that an increase in the Hartmann number suppresses the fluid velocity due to magnetic damping, whereas a higher Grashof number, a stronger electric field, enhanced heat generation, and reduced EDL thickness significantly augment the velocity and net flow rate. Among these parameters, the electric field is identified as the most dominant control mechanism, capable of substantially improving the pumping efficiency even in the absence of EDL modulation. The findings can offer conclusive guidelines to optimizing thermally controlled EMHD micropumps, which can be used as a backbone to advanced designs in biomedical and chemical microfluidic systems.