Increase Of Insulation Thickness Research Articles

Modelling mass transfer entrance lengths in turbulent pipe-flow with applications to small cathodes for measuring local mass transfer rates

Pipe-wall mass transfer, in the developing concentration boundary layer region, under fully developed hydrodynamic conditions is simulated with a low-Reynolds number,k−e, eddy viscosity turbulence model. The predictions are in good agreement with the electrochemical measurements of Berger and Hau, in the rangeRe=104 to 105, forSc=2244, and of Son and Hanratty, in the rangeRe=1×104–5×104, forSc=2400, in both the developing boundary layer region and the fully developed region. The application of small cathodes embedded in a larger active cathode to measure local mass transfer rates is also simulated. The size of the electrode and the thickness of the electrical insulation around the small electrode give rise to errors that increase as the insulation thickness increases and the electrode size decreases.

Insulated solar storage tanks

This paper presents the theoretical and experimental investigation of an insulated parallelepiped, outdoor solar, water-filled storage tank of size 1 m × 0.5 m × 0.3 m, that is made from galvanized iron. The absorption coefficient of the insulating material has been determined. The effects of plastic covers and insulation thickness on the water temperature and the energy gained or lost by water are investigated. Moreover, the effects of insulation thickness on the temperature profiles of the insulating material are discussed. The results show that the absorption coefficient decreases as the insulation thickness increases. Also, it is found that the glass wool insulation of 2.5 cm thickness has the best results compared with the other thicknesses (5 cm, 7.5 cm, and 10 cm) as far as the water temperature and the energy gained by water are concerned.

Programmed and oscillatory motion in Bridgman-Stockbarger growth

The response of the solid-liquid interface was derived for a mechanical drive which is either oscillatory or programmed for a linear change. Because the interface responds in a linear fashion, Laplace transforms prove very powerful for problems of this type. As might be expected, the amplitude of the freezing rate fluctuations decreases as the frequency of the mechanical drive rate fluctuations increases. The damping increases as the heat transfer coefficient decreases, ampoule diameter increases, temperature difference between heater and cooler decreases, and as the insulation thickness increases.