补风方式对中庭火灾燃烧及烟气扩散影响的实验研究

Experimental Study on the Effect of Supplemental Ventilation on the Fire Combustion and Smoke Diffusion in Atriums

补风系统是建筑火灾烟气控制系统的重要组成部分,补风气流对火源的燃烧及烟气的控制效果影响较大。本文利用缩尺实验研究了侧送和下送补风对火源燃烧和疏散通道内烟气控制效果的影响。结果表明,补风口高度的变化会引起火焰形状的变化,且补风口高度越低,火焰越宽,火源热释放率越大。侧送补风对火源的干扰较大,但能有效阻挡烟气在水平方向的扩散;较高楼层设置侧送补风会加速烟气的沉降,四层设置侧送补风时,烟气层可下降至0.3 m。下送补风对火源的干扰较小,但对烟气在水平方向扩散的控制效果较差;下送补风设置在二层及以上楼层时,烟气层可始终保持在1 m以上,能有效维持烟气层的稳定性。本研究结果有望为补风系统的设计提供参考。

The supplemental ventilation system is an important part of the building fire smoke control system,and supplemental air flow has a significant influence on the combustion of fire sources and the effect of smoke control.In this paper,a scale experiment was conducted to study the impacts of the breathing zone combined with underfloor supplemental ventilation on the combustion of fire sources and the effect of smoke control in evacuation passageways the.The results showed that the change of the height of air inlets will cause the change of the flame shape,and the lower the height of air inlets is,the wider the flame and the greater the heat release rate of fire sources will be.The breathing zone supplemental ventilation interferes with fire sources greatly,but it can effectively block the diffusion of smoke in the horizontal direction.The arrangement of breathing zone supplemental ventilation on upper floors will accelerate the settlement of smoke,and when the breathing zone supplemental ventilation is set on the fourth floor,the smoke layer can be reduced to 0.3 m.The underfloor supplemental ventilation brings less interference to fire sources,but its control effect on the diffusion of smoke in the horizontal direction is poor.When the underfloor supplemental ventilation is arranged on the second floor and above,the height of the smoke layer can always be maintained at more than 1 m,which can effectively maintain the stability of the smoke layer.The research results are expected to provide reference for the design of supplemental ventilation systems.