NUMERICAL SIMULATION LAMINAR NATURAL CONVECTION HEAT TRANSFER IN A RECTANGULAR ENCLOSURE WHEN ONE OF ITS VERTICAL WALLS IS HEATED PARTIALLY

Abstract

Two-dimensional natural convection heat transfer with a rectangular enclosure isexamined numerically. The left vertical wall is partially heated, the reminder of the walland the right wall is cooled to uniform temperature distribution, the top and bottom wallsare adiabatic. The theoretical study involved the numerical solution of the Navier-Stokesand energy equations by using finite difference method. The stream function–formulation is used in the mathematical model. The numerical solution is capable ofcalculating the stream function, vortices and temperature fields of the computationaldomain. A computer program in (FORTRAN 90) is used to carry out the numericalsolution. Problem has been analyzed and the non-dimensional governing equations aresolved using finite difference method. Enclosure is assumed to be filled with an air with aPrandtl number of 0.71. The problem is analyzed for different values of the Rayleighnumber in the range (103 ≤ Ra ≤ 5×105 ) and aspect ratio (0.5≤ AR ≤ 2). It is found thatfor small Rayleigh, the heat transfer is dominated by conduction and begins to bedominated by convection with increasing Rayleigh. In order to validate the numericalmodel, the results of variation local Nusselt number and a relation between averageNusselt number and Ra number, are compared with previous works, for square enclosurefilled by air (Pr=0.71). There are excellent agreements which validate the presentcomputational model.