Membrane-actuated pumping and heat transfer of a Jeffrey fluid in a vertical convergent-divergent porous microchannel

A biologically inspired membrane-based pumping system is developed to analyze the transport of Jeffrey fluids in a vertical convergent–divergent microchannel embedded in a porous medium under thermal radiation. The study investigates how vertical orientation, combined with converging–diverging geometry, influences fluid motion and heat transfer in microfluidic environments. Using lubrication theory and nondimensional analysis, the governing equations for mass, momentum, and energy are solved analytically.The convergent–divergent geometry enhances pressure rise, flow rate, and velocity profiles compared to uniform channels, while vertical orientation introduces buoyancy effects that further shape the flow. The porous medium adds resistance but enables controlled momentum and thermal transport, resulting in improved temperature and pressure distributions. Pumping is driven by periodic membrane oscillations that generate regulated pressure gradients and support unidirectional flow.Key parameters such as the Jeffrey fluid parameter, permeability, Grashof number, heat source parameter, and thermal radiation are examined for their influence on flow and thermal behavior. Entropy generation analysis provides insight into thermodynamic efficiency and optimal operating conditions.Overall, the work contributes to the design of efficient, controllable microfluidic pumping systems for biomedical and microscale engineering applications.