MHD thermosolutal convection in nanofluids with Soret and Dufour effects using a hybrid MRT-LBM FDM approach

This study develops a hybrid numerical model to simulate magneto-thermo-solutal convection in nanofluids, incorporating the Soret and Dufour effects. The model combines the Multiple Relaxation Time Lattice Boltzmann Method (MRT-LBM) for fluid flow, the BGK-LBM for solving the magnetic induction equation, and the Finite Difference Method (FDM) for heat and mass transport. Simulations are performed for Cu–H 2 O and Al 2 O 3 –H 2 O nanofluids in a lid-driven cavity, with parametric analyses of the Hartmann number (Ha) and cross-diffusion numbers (Sr = Df), under aiding and opposing buoyancy conditions. Results show that Cu–H 2 O provides better thermal and solutal performance than Al 2 O 3 –H 2 O at low Ha and N = +1. However, magnetic damping and opposing buoyancy (N = −1) reduce or reverse this advantage. The proposed model effectively captures the complex interplay between magnetic, thermal, and solutal effects, offering a robust framework for multi-physics transport simulations in nanofluids.