SE-99-15-3 -- Convective Heat Transfer from a Window with a Venetian Blind: Detailed Modeling ✓ Most Recent

The convective heat-transfer rate from a window surface to an adjacent venetian blind has been studied using a finite-element code. For this study, the window surface was modeled as an isothermal vertical flat plate, and the effects of radiation exchange between the window and blind were ignored. This investigation was undertaken to investigate the effects of blade-to-plate spacing d and blade angle T on the flow pattern and convective heat-transfer coefficients. Results are presented for values of d=15, 20, 25, 30, and 40 mm, and at each of these spacings, the blade angle was varied, i.e., q=0°, 45°, -45°, 80°. To support model development, the modeling of a common base case, i.e., the laminar natural convection on an isothermal, vertical flat plate, was studied. Comparisons with experimental results were also made for both local heat flux and flow distribution for d =15 mm. The results of this paper indicate that convective heat transfer from a vertical flat surface is influenced by the presence of a venetian blind. These results represent a first step in the analysis of the effects of venetian blinds on fenestration heat transfer. Future studies will investigate the effects of solar energy absorption in the blind surface and coupled convective/radiative heat transfer.

Units: SI