This work includes a numerical investigation of steady two dimensional laminar natural
convection heat transfer in glazed rectangular enclosure at different tilt angles ranged from (0o
to 90o) for Rayleigh number (103-106), aspect ratios(4,5, and 8),and Prandtl number (0.7). The
study considers the effect of different boundary conditions on the heat transfer within the
enclosure. The continuity equation, Navier-Stokes equations and the energy equation are
solved by developing a numerical model based on finite volume method using SIMPLE
algorithm with hybrid scheme to compute the velocity vectors, temperature, pressure, and
Nusselt No. (local and average). Results show an increase in heat transfer rate with increasing
of Rayleigh number, and for low Rayleigh numbers, the conduction is the dominant heat
transfer mode. At Ra= 103, the mean Nusselt number remains constant around unity for all
cases. The tilt angle has the major effect on the heat transfer for Rayleigh number larger than
104. A comparison of the present results with previously published data is conducted, and good
agreement is seen to indicate the effectiveness and flexibility of the developed numerical
procedure.