Numerical study of MHD mixed convection flow over a diamond-shaped obstacle using OpenFOAM

Abstract

The development of the flow structure with assisting the buoyancy in the liquid metal flow over the diamond-shaped obstacle and the influence of the presence of magnetic field on the vorticity and heat dissipation from the hot surface is investigated numerically at fixed Reynolds number of Re = 1000. The computation is performed by the in-house developed magnetohydrodynamics (MHD) based flow solver using open source CFD tool OpenFOAM. The liquid metal with a Prandtl number of Pr = 0.02 is considered as working fluid and is assumed to be electrically conducting in nature. The strength of the buoyancy in the flow is varied in the range of four different Richardson number of Ri = 0, 0.5, 1, and 5. The consequence of the rising buoyancy in the flow on the vorticity and time-averaged Nusselt number over the hot surface is observed. The unsteadiness in the flow due to the rise in the buoyancy is further controlled and regulated by the application of a magnetic field. The intensity of the magnetic field is governed by non-dimensional Hartmann number (Ha) varies in the range of Ha = 0–50. It is observed from the results that the Lorentz force in the flow opposes the Kármán vortex street and the buoyancy in the flow degenerates the vortex. The undulation in the heat transfer due to rise in the buoyancy is suppressed by the presence of Lorentz force without sacrificing the Nusselt number at low Hartmann number. The study of isotherms, streamlines, time-averaged Nussselt number, vorticity is discussed in detail.