室内准稳态压力火灾烟气沉降模型的改进和实验验证

对室内火灾及烟气的研究给消防工程领域带来了诸多益处,如疏散时间预测、基于性能化的设计分析等。Zukoski (Fireand Materials,1978,2(2): 54-62)在室内火灾烟气运动的开创性研究给出了基于质量和能量平衡的理论方法,为后续研究奠定了基础。然而实验发现,由于忽略热损失偏差,模型对近壁面火源的火灾烟气沉降时间的预测缺乏准确度。本文通过空间重构的方法消除房间长宽比因素造成的热损失偏差,引入两个参数进行表征,以完善该模型。完善后的模型预测烟气沉降时间与实验吻合度非常好,验证了该方法的有效性。在计算分析基础上,将两个参数对模型的影响作了评估,发现其一对模型预测结果的影响远大于另一参数。火源大小确定后,烟气充满房间的时间范围可确定,火源功率越大,时间范围越小。

Improvement and experimental verification of smoke subsiding model in quasi-steady pressure room fire

The research on the development of room fire and smoke movement has brought many benefits to fire engineering, including the prediction of evacuation time and performance-based design analysis. Zukoski (Fire and Materials, 1978, 2(2): 54-62) provided a theoretical analysis method based on mass and energy balance in the pioneering research of room fire smoke movement, which laid a foundation for the subsequent studies. However, due to the bias of heat loss, there is a big gap between the model and the experiment in predicting the subsiding time of fire smoke. In this paper, it is proposed that the heat loss bias caused by the ratio of length to width can be eliminated by the method of geometric space reconstruction, and two parameters are introduced to characterize and improve the model. The time of smoke subsiding predicted by the improved model agrees well with the time measured in the experiment, proving the validity of the method. Based on calculation and analysis, the influence of the two introduced parameters is evaluated, and it is found that one parameter has a much more significant impact on the prediction result than the other. Once the intensity of the fire source is determined, the time range of smoke filling the room can be determined, and the greater the heat release rate, the smaller the time range.