Numerical study of MHD natural convection flow inside a porous cavity with chemical reaction and Soret–Dufour effects

OpenAlex İngilizce

The increasing demand for efficient thermal management in advanced engineering systems has driven significant interest in the study of transport phenomena in non-Newtonian fluids within porous domains. Such configurations are commonly encountered in applications including energy storage systems, chemical reactors, and geophysical processes. In this context, the present work investigates the behavior of a Casson fluid undergoing 2D convective flow inside a porous chamber, with emphasis on the interaction between flow dynamics, mass and heat transmission. This analysis incorporates the combined influence of magnetohydrodynamics, volumetric heat generation, and chemical reaction, along with cross-diffusion mechanisms characterized by the Double-Diffusive effects. The inclusion of these phenomena introduces an additional coupling between the temperature and solutal fields, significantly altering the overall behavior within the cavity. This enclosure is subjected to time-dependent thermal forcing through sinusoidal oscillations applied to the vertical boundaries, while the horizontal walls are maintained under permeable boundaries. These arrangements generate a complex flow structure in which buoyancy-driven motion is strongly influenced by temporal boundary variations. The governing physical model is developed by using the Darcy formulation for porous media, combined with the Boussinesq approximation to represent density variations arising from temperature and concentration differences. The internal heat generation acts as a source term that elevates the fluid temperature. The governing equations for momentum, energy, and concentration are expressed in dimensionless form to identify the dominating governing parameters. These equations are then discretized using the finite difference technique, ensuring accurate spatial representation of the coupled transport processes. To obtain stable and efficient numerical solutions, a hybrid computational approach is adopted, integrating the Gauss-Jordan elimination and the Alternating Direction Implicit technique. The findings show that buoyancy enhancement intensifies circulation and strengthens heat and mass transport, while magnetic parameter and Casson fluid behavior suppress flow development and reduce velocity magnitude. The Rayleigh number is observed to be a dominant controlling parameter that significantly strengthens buoyancy-driven flow and enhances convective heat transfer with increasing magnitude. Furthermore, the combined effects of internal heat generation and the Dufour parameter intensify thermal gradients, producing increasingly distorted isotherms and enhanced energy transport within the cavity. In contrast, the Soret effect promotes species diffusion induced by temperature gradients, thereby substantially altering the concentration distribution and mass transfer charateristics.