Natural convection heat transfer from discrete heat sources in a three dimensional enclosure

Abstract

Flow in a rectangular enclosure with an uniform heat flux applied across the vertical sidewall and with the opposite vertical surface cooled to a uniform low temperature has been numerically studied. Computations has also been carried out for investigating the heat tral1sfer and now pattern inside that enclosure with uniform heat nux applied at the lower horizontal wall with the opposite horizontal surface cooled to isothermal low temperature. The remaining walls are kept adiabatic. In the numerical analysis the integral form of the governing equations are discretized to algebraic equations by using control volume based finite volume method with a body fitted grid. Monotone advection '. and reconstruction scheme and conjugate gradient scheme are used to solve the algebraic equations. The pressure-velocity coupling is achieved by Semi implicit pressure linked equation algorithm. Investigations are carricd out for fluid at Rayleigh number 103 to Rayleigh number 106 It has been assumed that the now is laminar. Boussinesq Approximation is used i.e. it is assumed that the fluid properties are constant except for the density range with temperature which gives rise to the buoyancy force. Investigations are carried out for different size of the enclosure (different aspect ratio) and different size of heated strip applied to the wall. Flow patterns in terms of velocity vector, Horizontal velocity, Vertical velocity, Isotherms, Temperature distribution and Nusselt Number distribution are used to analyze the result obtained. Effect of Rayleigh number and size of the heated strip on the horizontal and vertical velocity also predicted.