Investigating the influence of magnetic field on heat transfer in turbulent ferromagnetic fluid over a backward-facing step

In this research, we present a computational investigation into the behavior of turbulent ferromagnetic fluids flowing over a backward-facing step, influenced by an external magnetic field. Our model is subjected to a rigorous validation process to prevent error masking across various submodels. The study encompasses a range of Reynolds numbers (ReH) from 5000 to 80 000, expansion ratios (Er) from just above 1 to 2, Prandtl numbers (Pr) from 4 to 8, and Hartmann numbers (Ha) from 0 to 100. We introduce innovative correlations for the average Nusselt number, applicable in both the presence and absence of a magnetic field. These novel correlations are meticulously compared with existing empirical formulas, and their compatibility and discrepancies are critically analyzed. By incorporating a broader spectrum of physical phenomena, such as the braking effect of magnetohydrodynamics, the impact of the step geometry, the resulting recirculation zones, and the potential inaccuracies in calculating average velocity and Reynolds number, our new correlations substantially enhance the predictive accuracy of the average Nusselt number compared to previous models.