Free convection from a window glazing with a venetian blind: Numerical model development

The present numerical study examines the influence of horizontal louvres (Venetian blinds) on the convective heat transfer from a vertical isothermal surface. A steady, laminar, two dimensional, conjugate conduction/convection solution to this problem has been obtained using the finite element method. Detailed comparisons are made with temperature field and local Nusselt number data obtained using a Mach-Zehnder Interferometer. Also, numerically predicted stream function contours are compared to streamlines obtained from flow visualization experiments. All results are obtained for Pr = 0.7, as the intended application of this study is for air. Results show that as the blind tip-to-plate spacing decreases, the difference between numerical solutions and experimental results increase. This suggests that radiation heat transfer may be a significant factor at smaller blind spacings.