Doors And Windows Within The Gap Penetration Coefficient Of The Air Flow Characteristics And The Characteristics Of Air Infiltration Research And Applications

Along with the high-rise buildings unceasingly increasing, the problem on its air infiltration is more and more prominent, and the key link of infiltration study is the calculation on its amount of wind. The gap method is better than other methods to calculate the infiltration amount of wind through windows and doors gap, but the infiltration characteristic exponent of the gap method is influenced by some factors, such as differential pressure,fluid state,gap width,geometrical shape etc, It's Range of variation between 0.5-1.0, generally the exponent takes 0.67 In the project application, which will bring large error to infiltration wind calculation. Therefore, it is very important to the study of flow characteristic in gap and infiltration characteristic exponent.Based on above question and insufficiency, the thesis firstly used the method of CFD numerical simulation to study air flow characteristic of gap under microscopic criterion, and analyze some factors (differential pressure,fluid state,gap width,geometrical shape etc) to the infiltration characteristic exponent of influence. The primary completed research work is following items: the gap physical model were abstracted through analyzing the types of windows and doors, according to the Hagen-Poiseuille equation, deducing the relation between mass flow and differential pressure under the laminar conditions in long and narrow gap; Based on the numerical simulation, the infiltration characteristic coefficients a,b of some gap widths were worked out under all kind of type gaps, simultaneity, the error of the infiltration amount of wind was compared with b equal to 0.67; The empirical formula was inferred on infiltration characteristic constant and gap width through numerical fitting, the width range of straight gap and L type gap were deduced when the b took 0.67; Adopted the b value of relative error less than or equal to 3% as the chosen standard of differential pressure, which analyzed the b value to the influence of differential pressure; The fluid state can judged by the Reynold's number; Applied gap flow characteristic and the discipline of infiltration characteristic coefficient to study the air infiltration to the room of air quality influence.The conclusion of this thesis may apply directly in the project, it is important guiding significance to air infiltration calculation in theory.