Enhanced thermal stratification in a liquid storage tank with a porous manifold

Solar Energy ◽  
2011 ◽  
Vol 85 (7) ◽  
pp. 1409-1417 ◽  
Author(s):  
N.M. Brown ◽  
F.C. Lai
Keyword(s):  
Storage Tank ◽  
Thermal Stratification ◽  
Liquid Storage ◽  
Liquid Storage Tank

Measurement of Permeability and Slip Coefficient of Porous Tubes

Volume 1 ◽  
2004 ◽  
Author(s):  
N. M. Brown ◽  
F. C. Lai
Keyword(s):  
Reynolds Number ◽  
Wall Thickness ◽  
Storage Tank ◽  
Thermal Stratification ◽  
Porous Wall ◽  
Interface Condition ◽  
Outer Diameter ◽  
Slip Coefficient ◽  
Liquid Storage ◽  
Liquid Storage Tank

Experiments have been conducted to measure the permeability and slip coefficient of seven porous tubes. These tubes are to be used in a liquid storage tank to enhance thermal stratification. They were made from fiberglass and nylon nettings with various wall thicknesses. Six tubes had an outer diameter of 1.9 cm and a thickness ranging from 0.158 cm to 0.635 cm, and the seventh tube had an outer diameter of 10 cm and a thickness of 0.635 cm. Tests show that these tubes have a distinct permeability in the longitudinal and radial directions. As such, both permeabilities of the tubes were measured. In addition, the slip coefficient which is an important parameter in the Beaver-Joseph interface condition was determined. From the results obtained, one can conclude that both permeabilities depend on the material, but the radial permeability also depends on the wall thickness. The slip coefficient depends not only on the material but also on the Reynolds number, permeabilities and porous wall thickness.

Numerical Study of Thermal Stratification in a Liquid Storage Tank With a Porous Manifold

Solar Energy ◽  
2006 ◽  
Author(s):  
N. M. Brown ◽  
F. C. Lai
Keyword(s):  
Experimental Data ◽  
Reynolds Number ◽  
Storage Tank ◽  
Richardson Number ◽  
Thermal Stratification ◽  
Numerical Study ◽  
Temperature Fields ◽  
Liquid Storage ◽  
Wide Range ◽  
Liquid Storage Tank

A numerical model has been developed to study the effects of a porous manifold on thermal stratification in a storage tank. The model is used to predict the development of flow and temperature fields during a charging process. Computations have covered a wide range of the Grashof number (1.8 × 105 < Gr < 1.8 × 108) and Reynolds number (10 ≤ Re ≤ 104), or in terms of the Richardson number, 0.1 < Ri < 105. The results obtained compare favorably well with the experimental data. In addition, the present results have confirmed the effectiveness of porous manifold in the promotion of thermal stratification and provide useful information for the design of such system.

Experimental Study of Stratification in a Liquid Storage Tank With a Porous Manifold

Volume 4 ◽  
2004 ◽  
Author(s):  
N. M. Brown ◽  
F. C. Lai
Keyword(s):  
Experimental Study ◽  
Flow Visualization ◽  
Storage Tank ◽  
Richardson Number ◽  
Thermal Stratification ◽  
Thermal Storage ◽  
Stable Stratification ◽  
Height Ratio ◽  
Liquid Storage ◽  
Liquid Storage Tank

Experiments were conducted to investigate the effectiveness of a porous manifold in the formation and maintenance of thermal stratification in a liquid storage tank. A thermal storage tank with a capacity of 315 liters and a diameter-to-height ratio of 2 was used for the experiment. The porous manifold used was made from rolling up a nylon screen into the shape of a tube. Stratification was observed at a Richardson number as low as Ri = 0.615. Flow visualization was also performed to confirm the effectiveness of the porous manifold in the promotion and maintenance of stable thermal stratification. From the results of flow visualization, one can conclude that a porous manifold is able to reduce the shear-induced mixing between fluids of different temperature, and thus is able to promote and maintain a stable stratification.

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