Numerical study of convective and radiative heat transfer from a window glazing with a venetian blind

A two-dimensional numerical solution has been obtained of the effect of a v enetian blind on the conjugate heat transfer at an indoor window glazing. A solution has been obtained to the coupled laminar free convection and radi ation heat transfer problem, including conduction along the blind slats. Th e local convective Nusselt number distributions were found to compare well with published experimental data for an aluminum blind. Also, there was goo d qualitative agreement with temperature and flow field visualization photo graphs. The results show that, over a wide range of Rayleigh numbers, an al uminum venetian blind can have a strong effect on the heat transfer rate fr om the indoor window glazing. Depending upon the specific conditions, the a verage convective heat transfer rate can either increase or decrease. Howev er, for all cases studied, the blind was found to substantially reduce the radiative heat transfer rate from the window, even when the slats were full y open.