Study On The Ventilation Added Resistance Characteristics Of Perforated Curtain Wall

In recent years, with the diversified development of building materials, all kinds of perforation metal panel originally applied in the industrial field are widely used in building facade as curtain wall. In order to improve the building adornment effect, reduce the solar radiation, but also can increase the resistance of the vents in building external wall. This article adopts the methods of model test and numerical calculation to study influence of ventilation system after the vents are blocked by perforated curtain wall. And provide the foundation for the design of perforated curtain wall and ventilation system.Based on the similarity principle, this model test using a 1:4 scale-down model to study on the additional resistance characteristics which caused by perforated curtain wall. Firstly, calculated the size of test-bed and discussed the equivalence of square or circular duct in the flow and the installation size and height of curtain wall. Then set up the test-bed and measured the additional resistance caused by perforated curtain wall in three kinds of wind speed under the condition of intake/exhaust air. Finally expressed the additional resistance as a speed-independent coefficient, and analyzed the change laws of the additional resistance coefficient.According to the similarities of perforated curtain wall and porous medium, using two-dimensional porous-jump boundary instead of perforated curtain wall for resistance calculation. Firstly determine the relationship between pressure jump coefficient C, permeability a and aperture, perforation rate, perforation form, spatial arrangement and thickness of perforated curtain wall. Then calculation model is set up and numerical calculation methods and model are verified by comparison with experimental and simulation data.Finally using the validated calculation methods and model calculated the additional resistance characteristic of actual perforated curtain wall. The results shows that the additional resistance coefficient decreased exponentially with the increase of installation distance, and wind speed in the pipe and size of perforation are independent. When the perforation rate is between 20% to 50% and installation distance is 200mm to 1000mm, the relationship between additional resistance coefficient and installation distance can be expressed as Aξ=Aexp(BL). This paper also give the coefficient A and B values under different inlet and exhaust conditions.