Measurement of Permeability and Slip Coefficient of Porous Tubes

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.