Modeling and experiment on thermal performance of vacuum glazing

摘要

The simulation and experimental measurement method are carried out to study the insulation performance of vacuum glazing. The heat transfer mechanism of vacuum glazing has been simply reviewed firstly. Grid meshing method of heat transfer model for vacuum glazing geometry is achieved by results of different meshing methods in ANSYS WORKBENCH 13.0, which is used in heat transfer simulation of vacuum glazing. To ensure the accuracy of calculation, too dense meshing in pillar region is unnecessary, but grid refinement in the projection area of the upper and lower glass must be uniform and dense enough. Heat transfer coefficient of vacuum glass under different pressures has been gotten on the experiment device. A thermal conductivity curve that changes with pressure is 'S' shape. The pressure value at curve inflection point where the gas state shifts could be estimated by Knudsen coefficient. The gas is at the state of free molecule when pressure of the evacuated space between two parallel glass sheets lower 0.1 Pa. Then the reduction of pressure lower 0.1 Pa has little effect on heat transfer coefficient which also demonstrates in experiment.