Electrically Conducting MHD Casson Nanofluid Flow in a Uniform Transverse Magnetic Field over a Stretching Sheet

This study focuses on volumetric sensible enthalpy formulation of ethylene glycol-based nanofluids that replaces the conventional temperature-based energy equation. The nanofluid contains Al2O3 nanoparticles with volume fractions in the range (0.01≤φ≤0.05), consistent with experimentally investigated concentrations. Unlike conventional temperature-based energy formulations, the present approach describes thermal transport through volumetric sensible enthalpy, representing the sensible energy stored per unit volume of the nanofluid. This framework enables the analysis of coupled momentum, enthalpy, and nanoparticle transport in electrically conducting Casson nanofluids involving thermophoresis, viscous dissipation, and Joule heating. The governing momentum, enthalpy, and nanoparticle concentration equations were transformed into coupled nonlinear ordinary differential equations using similarity transformations and solved numerically using an adaptive collocation scheme (SciPy’s solve_bvp). Parameter effects are systematically evaluated, including the Casson parameter, magnetic field parameter, Schmidt number, Biot number, thermal and solute Grashof numbers, Brinkman number, Eckert number and thermophoresis parameter. The results show that the magnetic field parameter and Casson rheological effects strongly influence the momentum characteristics of the flow. Increasing the magnetic field parameter suppresses the velocity distribution through the Lorentz force while enhancing the volumetric sensible enthalpy due to Joule heating. The Eckert number produces a significant increase in volumetric sensible enthalpy owing to viscous dissipation, whereas the Schmidt number primarily controls nanoparticle concentration transport with only a weak influence on the enthalpy field. Thermal and solutal buoyancy parameters enhance fluid motion through buoyancy-driven convection, while thermophoresis promotes nanoparticle migration and moderately increases thermal energy storage within the boundary layer. In contrast, the Biot and Brinkman numbers exhibit limited influence on the velocity, volumetric sensible enthalpy, and concentration profiles within the considered parameter ranges. The proposed volumetric sensible enthalpy formulation provides an alternative framework for quantifying internal energy storage and redistribution in MHD non-Newtonian nanofluids. Potential applications include thermal energy storage, electronic cooling with nanofluids, polymer extrusion, magnetohydrodynamics (MHD) pumping, biomedical flows, solar thermal collection, and nuclear reactor cooling.