Fractional order transport modelling of MoS₂-vegetable oil nanofluid with hall, radiation and thermophoretic effects under isothermal and ramped boundary conditions

Abstract

This study investigates heat and mass transfer enhancement in unsteady MHD cross-diffusional Brinkman-type vegetable-oil based MoS2 nanofluid transport in the rotating system. The model accounts for the Hall current, thermophoresis, radiation, Brownian motion and chemical reactions under isothermal and ramped wall conditions. The modeled governing equations are generalized by using the Caputo-Fabrizio fractional derivatives with non-singular exponential kernel and the resulting system tackled by the finite difference scheme. Both velocity components raised with time factor and Hall effect but decayed with fractional-order and Brinkman parameters under both thermal conditions. The rotational effect in the system prompted to rise the secondary velocity and decline the primary velocity. The higher nanoparticle concentration in the fluid exhorted to substantial rise in the fluid temperature but both velocity components decelerated. A noticeable enhancement in the fluid temperature was observed under both thermal conditions with Joule heating, Dufour, radiation and thermo-Brownian effects. Both temperature and concentration fields enhanced by the fractional-order parameter under isothermal condition but lowered under ramped wall condition. Heat transfer rate raised with Prandtl number and reduced with Brownian-motion, radiation, thermophoresis and Dufour effects. Remarkably, heat transfer rate raised to 0.94% when adding 4% MoS₂ nanoparticles into the vegetable-oil base fluid.