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http://dx.doi.org/10.5407/jksv.2021.19.3.099

Effects of the aspect ratio and inlet velocity on the thermal stratification in a diffuser type seasonal thermal storage tank  

Kim, Seong Keun (Department of Mechanical Engineering, Chosun University)
Jung, Sung Yong (Department of Mechanical Engineering, Chosun University)
Publication Information
Journal of the Korean Society of Visualization / v.19, no.3, 2021 , pp. 99-105 More about this Journal
Abstract
In this study, the thermal stratification in solar seasonal thermal storage tanks was numerically simulated. The effects of the aspect ratio (AR) and inlet velocity on the thermal stratification in the diffuser type heat storage tank were investigated. The temperature distributions inside the tank were similar with velocity fields. Jet flows from opposite diffusers encountered each other at the tank center region. Thereafter, the downward flows occurred, and this flows strongly affected the thermal stratification. When AR was smaller than 2, these downward flows influenced a further distance and enhanced mixing inside the tank. Thermal stratification was evaluated by thermocline thickness and degree of stratification, and AR of 3 had the highest degree of stratification. The inlet velocity effect was expressed with the ratio (Re/Ri) of Reynolds and Richardson numbers. The second-order approximation was found for the relationship between the thermocline thickness and log Re/Ri.
Keywords
Seasonal thermal storage tank; Thermal stratification; Aspect ratio; Inlet velocity;
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