A NUMERICAL AND EXPERIMENTAL STUDY ON THE MIXING CHARACTERISTICS OF STRATIFIED THERMAL STORAGE |
Mi-Soo Shin1†, Hey-Suk Kim1, Dong-Soon Jang1, Sang-Nam Lee2, and Young-Soo Lee2 |
1Environmental Engineering Nat'l University of Chungnam, Daejon 305-764, Korea 2Utilized Energy Research Team, Korea Institute of Energy Research, Daejon 305-343, Korea |
Corresponding Author:
Mi-Soo Shin ,Tel: +82-42-821-6677, Fax: :+82-42-823-8362, Email: msshin@cnu.ac.kr |
Received: September 13, 2002; Accepted: December 15, 2002. |
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ABSTRACT |
A series of numerical and experimental works are performed for the determination of important design parameters and enhancement of the thermal storage efficiency with a bench scale facility. To this end a 2-D axi-symmetric computer program is developed. For this, a control-volume based finite-difference method is used with the Patankar's SIMPLE algorithm and power-law scheme for the interpolation of convection term.
The calculated temperature profiles with time along the vertical line of storage are compared with the measured ones. The temperature profiles are in general in good agreement especially at the early stage of hot water loading. Further the calculated flow characteristics are analyzed with the aid of the dye visualization experiment, which is injected in charging water. The mixing front shows quite stable and flat for the case of hot water charging from upper inlet, while the front movement of cold water charging from the bottom inlet is quite irregular. This observed difference of mixing front could be well explained by the significant difference of calculated streamlines of two cases.
In general the calculated results with major parameters such as inlet velocity, diffuser shape and diameter, baffles to control flow were physically acceptable and consistent. Further study is recommended to provide optimal determination of design parameters and operating condition for the case of full-scale storage.
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Keywords:
diffuser | SIMPLE | thermal storage tank | thermal stratification |
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