Joule heating and dissipation effects on thermal analysis of hybrid nanofluid flow between unevenly spinning plates saturated with variable porous medium

This study examines hybrid nanofluid flow through variable porous medium between two spinning disks. Both the disks rotate with varied angular velocities. The nanoparticles of Ag and TiO2 are mixed in H2O to fabricate a hybrid nanofluid. A magnetic field of intensity B0 is used in the normal direction of motion, with effects of Joule heating and viscous dissipation. The main equation of problem has been evaluated through homotopy analysis method. An increase in TiO2 and Ag + TiO2 nanoparticle concentrations, variable porous factor, and Reynolds number enhances axial momentum transfer, increasing radial and axial skin friction in both disks. When the volumetric fraction varies from 0.01 to 0.04, the heat transfer rate increases from 0% to 11.27% at the upper disk and from 0% to 15.46% at the lower disk, indicating the maximum percentage increase at the lower disk. The work has been validated through a comparative study of the current results with published work by ensuring a strong promise among all the results. The findings of this study offer valuable insights for optimizing cooling and thermal management in rotating machinery, turbine rotors, disk brakes, and energy devices, where hybrid nanofluids and porous media improve heat transfer and overall efficiency under Joule heating conditions.