From fire whirls to blue whirls and combustion with reduced pollution
From fire whirls to blue whirls and combustion with reduced pollution
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DOI：
10.1073/pnas.1605860113
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发表时间：
2016-08-23
影响因子：
11.1
通讯作者：
Oran, Elaine S.
中科院分区：
文献类型：
--
作者：
Xiao, Huahua;Gollner, Michael J.;Oran, Elaine S.
当大型城市和荒地火灾发生时，火旋风会给人们和周围环境带来强大的旋转灾难。尽管火旋风已被研究用于消防安全应用，但之前的研究尚未利用其潜在的燃烧效率来增强燃烧。本文介绍了对池火引发的火旋流的实验室研究，但燃料位于水面上，提出了利用火旋流的高效率来修复溢油的想法。我们展示了从池火到火漩涡，然后到以前未观察到的状态“蓝色漩涡”的转变。蓝色旋涡较小，非常稳定，燃烧时呈碳氢化合物火焰完全呈蓝色，表明无烟灰燃烧。快速混合、强烈涡流和水面边界的结合创造了几乎无烟灰燃烧的条件。随着世界范围内需要减少想要和不需要的燃烧的排放，这种状态的发现指出了减少燃烧排放和清理燃油泄漏的可能新途径。由于目前产生稳定涡旋的方法很困难，我们还建议蓝色涡旋可以作为流体力学中涡旋和涡旋破裂的基础研究的研究平台。
Fire whirls are powerful, spinning disasters for people and surroundings when they occur in large urban and wildland fires. Whereas fire whirls have been studied for fire-safety applications, previous research has yet to harness their potential burning efficiency for enhanced combustion. This article presents laboratory studies of fire whirls initiated as pool fires, but where the fuel sits on a water surface, suggesting the idea of exploiting the high efficiency of fire whirls for oil-spill remediation. We show the transition from a pool fire, to a fire whirl, and then to a previously unobserved state, a "blue whirl." A blue whirl is smaller, very stable, and burns completely blue as a hydrocarbon flame, indicating soot-free burning. The combination of fast mixing, intense swirl, and the water-surface boundary creates the conditions leading to nearly soot-free combustion. With the worldwide need to reduce emissions from both wanted and unwanted combustion, discovery of this state points to possible new pathways for reduced-emission combustion and fuel-spill cleanup. Because current methods to generate a stable vortex are difficult, we also propose that the blue whirl may serve as a research platform for fundamental studies of vortices and vortex breakdown in fluid mechanics.