An experimental study of the blue whirl: Effect of fuel surface diameter
An experimental study of the blue whirl: Effect of fuel surface diameter
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DOI：
10.1016/j.combustflame.2024.113322
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发表时间：
2024-03
影响因子：
4.4
通讯作者：
Huahua Xiao;Zixian Chen;Xing Li;Xiaohan Wang
中科院分区：
文献类型：
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作者：
Huahua Xiao;Zixian Chen;Xing Li;Xiaohan Wang
液体燃料表面直径通常是池火的重要影响因素。本文研究了液体燃料表面直径对倾斜10度的凹凸光滑金属表面形成的蓝色旋涡火焰动力学的影响。结果表明，液体燃料表面直径对蓝涡的形成和演化有显著影响。当燃料表面直径在25mm <d< 50mm范围内时，可形成稳定的蓝色漩涡。当≥50mm时，蓝旋涡变得不稳定，即在蓝旋涡的包络中心区域产生黄色旋转火焰，形成过渡状态。随着燃料表面直径的增大，蓝色旋涡的循环和火焰宽度均呈近线性增长。蓝旋稳定状态下火焰边缘升力高度随燃料直径呈线性变化，过渡状态下火焰边缘升力高度基本保持不变。蓝涡火焰进动频率随环流的增加而线性增加，进动半径基本保持不变。蓝色涡流单位面积的质量燃烧速率随燃料表面直径的增大而减小。基于辐射理论建立了蓝旋涡的辐射传热模型，并利用该模型和实验测量得到了蓝旋涡稳定态和过渡态的修正燃烧速率表达式。在量纲分析的基础上，提出了进一步预测蓝旋火焰几何特征和火焰进动频率的标度规律。这项工作提供了不同燃料表面直径的火焰动力学实验和对蓝色漩涡物理的见解。
Diameter of liquid fuel surface is generally an important factor for pool fires. This work studies the effect of diameter of liquid fuel surface on the flame dynamics of the blue whirl formed on a concaved smooth metal surface with a 10-degree inclination. The results show that diameter of liquid fuel surface has a significant influence on the formation and evolution of the blue whirl. When the fuel surface diameter is in the range of 25 mm <d< 50 mm, a stable blue whirl can be formed. Whend≥ 50 mm, the blue whirl becomes unstable, that is a yellow whirling flame is generated in the center region of the envelope of the blue whirl, forming a transitional state. As the fuel surface diameter increases, both the circulation and flame width of the blue whirl show a near-linear growth. The liftoff height of the flame edge in the stable state of blue whirl varies linearly with fuel diameter, while remaining almost constant in the transitional state. Whereas the flame precession frequency of blue whirl increases linearly with the increase of circulation, the precession radius keeps nearly constant. The mass burning rate per unit area of the blue whirl decreases with increasing the fuel surface diameter. A radiative heat transfer model for the blue whirl is established based on radiation theory, and the modified burning rate expressions for the stable and transitional states of the blue whirl are obtained using the model and experimental measurements. Further scaling laws, based on dimensional analysis, are proposed for predicting the flame geometric features and flame precession frequency of the blue whirl. This work provides experiments of the flame dynamics at various fuel surface diameters and insights into the physics of the blue whirl.