High-Rayleigh-number thermal convection of compressed gases in inclined rectangular enclosures

Abstract

High-Rayleigh-number convection is experimentally studied using compressed gases for a wide range of Rayleigh numbers (1.85 × 106 ≤ Ra ≤ 1.04 × 1011) and angles of inclination (θ = 0°, 30°, 60°, 90°, 120°, and 150°) with rectangular enclosures of varied aspect ratios (AR = 1, 3, 6, and 10). Experimental results reveal that the Nusselt number decreases monotonically with increasing angle of inclination. Furthermore, for any angle of inclination and a given Rayleigh number, the Nusselt number is observed to follow a decreasing trend with an increase in aspect ratio, which gradually amplifies as the angle of inclination is increased. Z-type shadowgraph flow visualization experiments, employed to characterize buoyant flow behavior at various angles of inclination, confirm the observed heat transfer trends.