Mesoscopic Lattice Boltzmann Numerical Model for Magnetohydrodynamic Thermosolutal Convection with Soret and Dufour Effects

This study investigates magnetohydrodynamic (MHD) double-diffusive convection in a driven cavity, considering the Soret (thermal diffusion) and the Dufour (diffusion-thermo) effects. A novel hybrid numerical scheme is proposed, combining the multiple relaxation time (MRT) lattice Boltzmann method (LBM) for the velocity field, the single relaxation time LBM (SRT-LBM) for the magnetic field and the finite difference method (FDM) to solve the energy and species balance equations. The proposed model has been validated against benchmark results from the literature, demonstrating good agreement. Numerical simulations reveal that the flow structure, isotherms and isoconcentrations are significantly influenced by the magnetic field under both aiding and opposing flow situations. The magnetic field substantially alters flow dynamics, with stronger fields dampening buoyancy- and shear-driven vortices, resulting in a more stratified velocity, temperature and concentration distribution. As the Hartmann number increases, convective heat and mass transfer are significantly suppressed, leading to a transition to conduction- and diffusion-dominated regimes. Additionally, the computed average Nusselt and Sherwood numbers provide valuable insights into the heat and mass transfer characteristics under varying magnetic field strengths. Furthermore, the proposed numerical model can exhibit potential for use in a range of industrial and engineering applications, offering the capacity to provide outcomes of benchmark quality.