Heat transfer enhancement in electroosmotic and ciliary-induced hybrid nanofluid flow with nonlinear thermal radiation effects

Abstract

This study develops a comprehensive mathematical model to examine the combined effects of electroosmotic forcing and cilia-driven peristaltic motion on the transport and thermal behavior of hybrid nanofluids (HNFs) in a microchannel actuator system. The working fluid comprises a mixture of magnesium oxide (MgO) and molybdenum disulfide (MoS 2 ) nanoparticles suspended in a base fluid with favorable biocompatibility and thermal stability. The model incorporates nonlinear thermal radiation, Joule heating, and thermal slip boundary conditions to accurately capture real microfluidic effects. The governing equations for momentum and energy conservation are derived under the assumptions of low Reynolds number and long wavelength approximation. To simplify the nonlinear electro-kinetic model, lubrication theory is applied to reduce the complexity of the flow domain, while retaining the full nonlinearity of the Poisson–Boltzmann equation to accurately capture the electrostatic potential distribution. The resulting coupled, dimensionless nonlinear partial differential equations are discretized and solved numerically using the finite element method (FEM) with appropriate boundary conditions. Parametric studies reveal that increasing the thermal slip parameter leads to a 21.6 % rise in wall temperature, due to reduced thermal resistance at the fluid–solid interface. Additionally, the axial velocity profile shows a 33.2 % enhancement with electroosmotic velocity parameter.