Study on Improvement of Effective Volume Ratio in Multi-Connected Thermal Storage Tank

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It is important to design multi-connected water thermal storage tanks with high effective volume ratio. In this project, effect of the connecting opening size and position and the velocity profile in the connecting opening on mixing property of the storage tank were studied by means of experiments and simulations as follows :1. Effect of the connecting opening size and position were studied by three type experiments which had the connecting opening of different size and position. In case of large storage temperature difference or little water flow rate, it was found that the position of the connecting opening has great effect on the mixing property in the tank because of buoyant bypass flow.2. The velocity profile in the connecting opening was calculated with a model derived from the Bernoulli's equation. The static water pressure difference between both side of the opening was obtained from flow rate and water density of both side tanks. The calculated velocity profile agreed well with experiment results. Two models were studied as mixing model in the tank under high temperature input from bottom opening. The one is a model in which flow rate is distributed from the opening to water surface linearly. The other is a model in which a buoyant plume is formed upward from the opening. The plume model was proven to be superior physically and calculated temperature profiles in the tank agreed roughly with the experiment results.