Natural Convection in Horizontal Duct Connecting Two Fluid Reservoirs

Abstract

The paper reports an experimental study of natural convection between two water reservoirs connected through a two-dimensional horizontal duct. The flow field was visualized and the velocities were measured using the thymol blue pH indicator method. The temperature field in the duct region and the heat transfer rate through the duct were also measured. It is shown that the duct flow consists of two streams in counterflow, the warmer stream occupying the upper half of the channel. The two streams are insulated from one another by a mid-depth buffer layer. The measurements demonstrate that the heat transfer mechanism differs fundamentally from the mechanism envisioned in the Bejan and Tien theory [6]. It is also suggested that the basic design of the experimental apparatus can be used in future studies of stability of shear flows in stratified fluids.