Numerical simulation of heat transfers in a room in the presence of a thin horizontal heated plate

In this work, we present a numerical study of heat transfer by natural convection in a two-dimensional closed room, containing air, in the presence of a thin heater plate. The vertical walls are kept adiabatic, while the horizontal ones are isothermal. The equations governing the natural convection in the room are solved using a finite difference technique based on the control volume approach and the SIMPLEC (Semi-Implicit-Method for Pressure-Linked Equations Corrected) algorithm. A non-uniform mesh in both directions, constructed by using a geometric progression, is adopted. The square room contains a thin heated plate located at the room center with an aspect ratio equal to 0.5. The heater plate is positioned horizontally and has a higher temperature than the isothermal walls. The simulation results are obtained in terms of velocity vectors and isotherms for different Rayleigh numbers values ranging from 10(4) to 10(6). The symmetric boundary conditions produce a symmetric behaviour of temperature and velocity fields according to the central vertical plan. The increase of Rayleigh number leads to increasing importance of convection heat transfer relative to the conduction heat transfer. The fact is more marked for the regions above the heater plate. It is shown that for high Rayleigh numbers, heat transfer from the heater plate to the isothermal horizontal walls is mainly directed towards the top wall. (C) 2013 The Authors. Published by Elsevier Ltd.