Combined Convection Turbulent Heat Transfer in a Vertical Duct : Opposing Flow

Abstract

An opposing flow of turbulent combined convection in a vertical duct was investigated experimentally. Compared with the forced convection, heat transfer coefficients in the combined convection regime were found to increase. It was realized that heat transfer promotion also occurred in a vertical duct. Then, the wall temperature patterns were also discussed from visualized data using liquid crystal. It was found that low-temperature streaks appeared on the wall, and that they played a significant role in heat transfer.