摘要

The free convective heat transfer in an idealized double-glazed window with a between-panes louvered (venetian-type) blind has been studied using laser interferometry. A Mach-Zehnder interferometer has been used to obtain full-field temperature visualization, as well as local and average convective heat transfer rates. A blind consisting of seventeen horizontal aluminium slats was mounted inside a tall vertical “window” enclosure. Optical measurements were obtained for three plate spacings and three blind slat angles over a Rayleigh number range (based on the enclosure width) of 4.6×10⁴ ≤ Ra ≤ 1.3×10⁵. The experimental results show that the louvered blind has a strong influence on the convective heat transfer within the enclosure. At narrow glazing spacings, an open blind (φ=0°) forms a thermal bridge across window, substantially increasing the convective heat transfer rate. In contrast, when the slats are fully closed, the blind effectively partitions the enclosure and the convective heat transfer rate is reduced. The experimental results have also been compared to predictions from a recent two-dimensional numerical solution.