Abstract The effect of cross-wind on the temperature elevation in the downwind region of rectangular diffusion burners was investigated in wind tunnel experiments. The experimental parameters were the geometry of the diffusion burner (the side length parallel and orthogonal to the cross-wind L 1 = 0.2 – 0.8 m and L 2 = 0.4 – 2.0 m , respectively, and the aspect ratio r = 1 – 10 ), the heat release rate ( Q ˙ = 38.3 – 383.3 kW ), and the inflow velocity of the cross-wind ( U ∞ = 0.59 – 1.49 m / s ). Following the concept of the previously proposed point fire source model, the fractional contribution of the cross-wind velocity on the velocity along the trajectory N was introduced to close the system of governing equations, and a relevant line fire source model was derived. The line fire source model was correlated by the measurement results of the present experiment for the diffusion burner with the largest aspect ratio ( r = 10 ). Although the predicted temperature elevation along the trajectory by the present model was similar to that of the existing models, there was a substantial discrepancy in the predicted trajectory. For the unified analysis of temperature elevation and trajectories of the fire sources with various aspect ratios, the point fire source model was firstly tested to correlate the measurement results. As expected, the agreement was less successful for the results of the fire sources with large aspect ratios, especially in the region close to the fire source. Thus, the point fire source model was modified to consider the physical effects of the aspect ratio of the fire source and the attachment of the fire plume to the ground by invoking the correlations for the line fire source. With the modified model, the agreement between the predicted and measured results significantly improved. The proposed model is useful for assessing the hazards of wind-blown fire plumes in large outdoor fires on human activities such as firefighting or the evacuation of residents.

中文翻译：

---

侧风下矩形火源下风区温升及轨迹

摘要 通过风洞实验研究了侧风对矩形扩散燃烧器下风区温度升高的影响。实验参数是扩散燃烧器的几何形状（与侧风平行和正交的边长分别为 L 1 = 0.2 – 0.8 m 和 L 2 = 0.4 – 2.0 m，纵横比 r = 1 – 10 ） , 放热率 ( Q ˙ = 38.3 – 383.3 kW ) 和侧风的流入速度 ( U ∞ = 0.59 – 1.49 m / s )。遵循先前提出的点火源模型的概念，引入侧风速度对沿轨迹 N 的速度的分数贡献来闭合控制方程组，并推导出相关的线火源模型。线火源模型与本实验对具有最大纵横比（r=10）的扩散燃烧器的测量结果相关联。虽然本模型预测的沿轨迹温度升高与现有模型相似，但预测轨迹存在很大差异。为了统一分析不同纵横比火源的温升和轨迹，首先对点火源模型进行了测试，对测量结果进行了关联。正如预期的那样，对于具有大纵横比的火源的结果，该协议不太成功，尤其是在靠近火源的区域。因此，通过调用线火源的相关性，对点火源模型进行了修改，以考虑火源纵横比和火羽对地面的附着的物理影响。使用修改后的模型，预测结果和测量结果之间的一致性显着提高。所提出的模型可用于评估大型室外火灾中风吹火羽对消防或居民疏散等人类活动的危害。