上、下悬窗自然排烟能力对比研究

通过数值模拟，研究了开窗角度对上、下悬窗排烟能力的影响，主要从排烟量、排烟口压力和速度、主要排烟区域等方面对上、下悬窗排烟能力进行对比分析，结果表明：下悬窗排烟效率明显高于上悬窗，相同开窗角度和火源功率下，下悬窗能比上悬窗多排出52%~61%的烟气。上悬窗相对排烟量与开窗角度成指数关系，窗体结构会阻碍烟气排出，开窗角度小于64°时，主要排烟区域为窗体两侧三角形区域；下悬窗相对排烟量与开窗角度关系不大，窗体结构对排烟有利，开窗角度小于56°时，主要排烟区域为近窗下侧水平区域，随着开窗角度增大，上、下悬窗主要排烟区域均过渡到远窗下侧竖直区域。建筑选择排烟窗时建议优先选用下悬窗，开窗角度30°即可，若选用上悬窗，则开窗角度不宜小于60°。

The comparative research on natural smoke exhaust capacity of top and bottom hung windows

The numerical simulation is used to study the influence of opening angle on the natural smoke exhaust ability for top and bottom hung windows. The smoke exhaust capacity of the top and bottom hung windows are evaluated by analyzing the mass flow, pressure and speed of the smoke outlet, and the main smoke exhaust area. The results show that the smoke exhaust efficiency of the bottom-hung window is obviously higher than the top-hung windows. Under the same o-pening angle and fire source power, the bottom-hung window c-an discharge 52% ~61% more smoke than the top-hung window. The relative mass flow of the top- hung window has an exponential relationship with the opening angle because the window structure is hindering the exhaust of smoke. When the opening angle is less than 64°, the main smoke exhaust area is the triangular area on both sides of the window, while the relative mass flow of the bottomhung window has little relationship with the open angle, and the window structure is beneficial to discharge smoke. When the opening angle is less than 56° , the main smoke exhaust area is the horizontal area near the lower side of the window, as the opening angle increases, the main smoke exhaust areas of the top and bottom hung windows transition to the vertical area under the far window. When choosing exhaust windows for buildings, it is recommended that bottom- hung window should be preferred, and the opening angle is 30° ; if top-hung window is selected, the opening angle should not be less than 60°.