مرکز منطقه ای اطلاع رساني علوم و فناوري

Abstract :

In this study, the effects of the gas layer thickness between the two panes of the double-pane window on the heat transfer is numerically investigated. Calculations with different values of the gas layer thickness (6, 9, 12, 15, 18, 24, 27 and 30 mm) are realized for dry air and argon at atmospheric pressure of 101325 Pa, dry air at vacuum pressure of 50663 Pa. In the calculations, on the outer surface facing outside forced convection with 6 W/m^2K at 258 K, on the outer surface facing inside natural convection at 293 K is applied. Only natural convection and conduction is considered by neglecting radiation heat transfer as heat transfer mechanism. Before the main calculations, the most reasonable turbulence and wall function model for numerical natural convection calculations for the vertical faces with 343 K constant temperature is searched. The comparison of numerical results with experimental results of the literatüre indicated that the most acceptable model and wall function is RNG (Renormalization Group) k-e turbulence model and enhanced wall treatment. All the calculations are performed by a commercial CFD code FLUENT. The results for different thickness of the gas layer exhibited that the heat loss through the double pane window is decreased up to the critical value. The thickness values more than critical value caused constant heat transfer. Critical gas layer thickness is 12 mm for dry air and argon at 1 atm pressure, 24 mm for dry air at vacuum pressure (vacuum). Heat saving rates achived are determined as 55% with air as minimum value and as 63% with argon as maximum value.