Heat and mass transfer in magnetic Casson nanofluids flow with radiation and stratification effects: Thermal management applications

Convective boundary conditions and nonlinear stratification play a vital role in controlling heat and mass transport in nanofluids, ensuring reliable thermal and solutal distributions. These mechanisms are particularly significant in engineering and biomedical applications where stability and efficiency are essential. Motivated by these applications, the present study investigates the flow of a cubic doubly stratified rotating Casson nanofluid over an inclined bidirectional stretching sheet, incorporating the combined effects of mixed convection, velocity slip, Darcy and non-Darcy porous media, and an oblique magnetic field. Additional physical processes, including thermal radiation, viscous dissipation, heat generation/absorption, Brownian diffusion, and thermophoresis, are integrated into the model to provide a comprehensive analysis of heat transfer behavior. The governing nonlinear ordinary differential equations are derived and numerically solved using Mathematica's NDSolve technique with high accuracy. The results reveal that magnetic and Darcy parameters suppress both primary and secondary velocity fields, while the thermal Biot number and radiation parameter enhance fluid temperature. Solutal Biot number increases nanoparticle concentration, whereas Brownian diffusion reduces it. Thermal and solutal stratification parameters weaken temperature and concentration distributions, respectively, whereas higher Biot numbers counteract these effects, promoting uniform profiles. The results highlight the vital influence of stratification and boundary conditions in optimizing heat and mass transfer, with direct relevance to semiconductor manufacturing, solar collectors, and polymer processing.