上、下悬窗阻风能力对比研究

环境风会改变排烟窗附近的烟气流向和速度,影响建筑内烟气流动,进而导致建筑自然排烟效率受到影响。采用数值模拟方法,对比研究了排烟窗开启角度和环境风对上、下悬窗阻风能力的影响,分析了不同开窗角度下,悬窗进风量和进风区域随开窗角度和风速的变化规律。结果表明:上、下悬窗相对进风量与开窗角度均成指数关系,但上悬窗阻风能力弱于下悬窗,上悬窗开窗角度大于45°后即失去阻风能力,而下悬窗开窗角度大于75°后才逐渐失去阻风能力,且开窗角度小于30°时,下悬窗至少能比上悬窗多减少50%空气进入室内。上悬窗开窗角度小于56°时,主要进风区域为近窗下侧水平区域;下悬窗开窗角度小于30°时,主要进风区域为窗体两侧及远窗下侧竖直区域,随着开窗角度增大,上、下悬窗主要进风区域均过渡到远窗下侧竖直区域。窗体用于日常通风时建议优选上悬窗。若要用于排烟,则应首选下悬窗,开窗角度15°即可满足阻风要求,若选用上悬窗,开窗角度不宜大于45°。

Comparative research on the capacity of restraining wind of top and bottom hung windows

The efficiency of natural smoke exhaust is affected by the building environmental wind. In this paper, a numerical simulation is used to compare the influence of opening angle and environmental wind on the capacity of restraining wind, and investigate the wind intake volume and area of the hung window with different opening angles and wind speeds. The results show that the relative air intake of top and bottom hung windows has an exponential relationship with the window opening angle, and the capacity of restraining wind of the top-hung window is weaker than the bottom-hung window. When the opening angle of the top hung window is greater than 45°, the wind-blocking ability will be lost, while for the bottom hung window, only when the opening angle is greater than 75°, the wind-blocking ability will be gradually lost. When the opening angle is less than 30°, the bottom-hung window can decrease 50% more air than the top-hung window. When the top hung window opening angle is less than 56°, the main wind intake area is the horizontal area near the lower side of the window. When the bottom hung opening angle is less than 30°, the main wind intake area is the triangular area on both sides of the window and the vertical area under the far window. As the opening angle increases, the main wind intake areas of the top and bottom hung windows change to the vertical area under the far window. The top-hung window is preferred for choosing windows for daily ventilation. For smoke exhaust, the bottom-hung window should be used with an opening angle of 15°. If a top-hung window is selected, the opening angle should be lower than 45°.