Extinguishing class B fires with dry chemicals: Scaling studies
Extinguishing class B fires with dry chemicals: Scaling studies
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使用干粉灭火剂扑灭 B 类火灾：规模研究
DOI：
10.1007/bf01305266
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发表时间：
1995
期刊：
影响因子：
3.4
通讯作者：
Homer W. Cathart
中科院分区：
文献类型：
--
作者：
C. Ewing;F. Faith;J. Romans;C. W. Siegmann;R. J. Ouellette;J. T. Hughes;Homer W. Cathart
在火焰灭火的持续研究中，1，2，3，4WE报告了对较大的庚烷扩散火焰(0.29平方米和2.32平方米平底锅)上干化学品的结垢研究。我们再次证明，小颗粒最有效地熄灭。灭火与分解或蒸发颗粒所吸收的热量有关。我们表明，对于所研究的系统，每种干化学物质的极限颗粒尺寸--即在火焰中完全分解或蒸发的最大颗粒尺寸--与火焰尺寸无关。我们将潜在或最大有效2，3的概念扩大并应用于各种规模的平火。最后，我们描述和表征了粉末传输中的空气动力学效应，即大颗粒以更高的动量卷进并将更小、更有效的颗粒拖入火焰中。我们还表明，消光曲线，包括实际与潜在消光重量的比率以及小颗粒与大颗粒的比例，对于大多数干化学品来说，具有可预测的形状和可预测的定量水平。我们已经开发了真实到潜在的概念，以及用于试剂混合物和广泛范围的试剂和颗粒大小的标度方程。
In a continuing study of flame extinguishment,1,2,3,4we report on scaling studies for dry chemicals on larger heptane diffusion flames (0.29 m2and 2.32 m2pans). We demonstrate again that small particle sizes extinguish most effectively. Extinguishment is related to heat absorption by decomposing or vaporizing particles. We show that the limiting particle size for each dry chemical—that is, the maximum size which completely decomposes or vaporizes in the flame—is independent of flame size for the systems studied. We broaden and apply the concept of latent or maximum effectiveness2,3to pan fires of all sizes. Finally, we describe and characterize an aerodynamic effect in the transport of powders, where large particles with their higher momentum entrain and drag smaller, more effective particles into the flame.We also show that extinction curves, involving the ratio of real-to-latent extinction weight and the proportion of small to large particles, have predictable shapes and predictable quantitative levels for most dry chemicals. We have developed the real-to-latent concept along with scaling equations for agent mixtures and for a wide spectrum of agents and particle sizes.