1987 Volume 12 Issue 35 Pages 95-103
This report describes an experimental study carried out to investigate the effects of the installation of a horizontal baffle plate in a rectangular thermal storage water tank on the flow behaviour in the tank and the thermal characteristics of the tank, by flow visualization and the measurement of transient water temperature response for the case in which hot water was discharged through a rectangular duct into the upper part of the tank filled with cold water. Experimental parameters varied included hot-cold water temperature difference, flow rate, duct width and baffle plate length. From the experimental results, semi-empirical equations suitable for predicting the dimensionless equivalent tank height of the amount of mixed cold water into hot water region, Δh/b, and the thermal storage efficiency in the arbitrary region of the tank, η_<V'>, were both deduced as the functions of the Archimedes number based on inflow conditions, Ar_0, the Peclet number of liquid, Pe, and two dimensionless geometric parameters φ_1 and φ_2. The general conclusion reached was that, for relatively low Archimedes numbers, the installation of a baffle plate contributed to improve the thermal storage efficiency appreciably due to the prevention of the occurrence of short-cut flow.
