A numerical model was used to simulate the two-dimensional flow of chilled water into a storage tank initially filled with warm water. The inlet flow is from a small slot in one vertical wall at the bottom of the tank. The numerical model employs a transient stream function-vorticity formulation to predict the streamline and temperature distribution in the tank as a function of time. Turbulence was modelled using the turbulent kinetic energy and turbulent length scale equations. The model results for a side-slot inlet to the tank reveal that the Archimedes number should be greater than 5 and the Reynolds number should be smaller than 1,000 to ensure thermal stratification of the hot and cold water. When stratification is achieved, the temperature distribution varies only in the vertical direction of the tank, where the water temperature is approximately uniform in the horizontal direction. The numerical results are in reasonably good agreement with some experimental data available in the literature.

KEYWORDS: temperature stratification, chilled water supply, energy storage, water tanks, calculating, streamline flow, temperature distribution, turbulent flow, Archimedes numbers, Reynolds numbers, water temperature