Effect of thermal radiation on MHD mixed convection in a bottom heated cavity with inner rotating conductive cylinder using Al₂O₃ water nanofluid

Abstract

The effect of radiation in mixed convection flow and heat transfer characteristics of nanofluid inside a bottom-heated lid-driven cavity under the presence of a uniform magnetic field with an inner rotating solid circular cylinder at the center of the enclosure have been investigated numerically. The sidewalls of the cavity are thermally insulated, and the top lid, kept at a constant cold temperature , moving with a uniform velocity of . The bottom wall of the cavity, which is of dome shaped, kept at a constant high temperature of . The solid cylinder of uniform conductivity placed at the center of the cavity is rotating counterclockwise at a uniform rotational speed of . The physical problem is represented by a set of governing equations along with the corresponding initial and boundary conditions using proper transformations. Both the governing equations and the boundary conditions were transformed into non-dimensional form, later those were solved using the Galerkin weighted residual technique based on the finite element method. The results are presented in terms of isotherms, streamlines, average Nusselt number, and an average temperature of the domain for different combinations of the non-dimensional parameters named as Richardson number(0.01-10), Hartmann number (0-45) , Reynolds number (50-200), Radiation Parameter (0-5), solid volume fraction of the nanoparticle (1%-15%) and the clockwise (CW) and counterclockwise(CCW) rotational speed of the cylinder (0-10). The results conclude that the fluid flow, heat transfer rate and average temperature of the domain strongly depends on the prementioned parameters. The average temperature, heat transfer rate increases with the increase in the value of the parameters Rd, Ri, rotational speed, and solid volume fraction on the other hand opposite phenomenon happens in the case of Magnetic parameter (Ha).