Flow and heat transfer due to partially heated moving lid in a trapezoidal cavity with different constraints at inner circular obstacle

Abstract

The main emphasis of the current work is to deal with the forced convection of magnetohydrodynamics (MHD) flow and its heat transfer due to force convection generated by a moving lid in a trapezoidal enclosure. Various cases of temperature at the surface of the circular obstacle inside the cavity are determined. The trapezoidal cavity has a moveable and partially heated top lid while the bottom wall is kept at a low temperature. The linearly inclined walls on the left and right sides of the cavity are both adiabatic. The finite element method is applied for computations validated with existing work. Numerical simulations are conducted to analyze this trapezoidal cavity model for various thermal conditions of the inner circular obstacle, various heated lengths (0 ≤ LH ≤ 1), various Reynolds number (100 ≤ Re ≤ 700), Richardson number (0.001 ≤ Ri ≤ 10) and Hartmann number (0 ≤ Ha ≤ 100). The entire analysis describes that high Reynolds numbers improve the thermal performance of liquid. However, moving lid generates fluid molecules specifically directed according to wall movement. The force convection phenomenon becomes more dominant as the Reynolds number and heated length increase. A cold circular obstacle resists the circulation of heat in the cavity whereas the local Nusselt number drops when the simultaneous effects of the moving lid force and heated sources move away from the surface.