Radiative, thermal, and kinetic regimes of opposed-flow flame spread: A comparison between experiment and theory
Radiative, thermal, and kinetic regimes of opposed-flow flame spread: A comparison between experiment and theory
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DOI：
10.1016/j.proci.2016.06.025
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发表时间：
2017-01-01
影响因子：
3.4
通讯作者：
Ferkul, Paul
中科院分区：
文献类型：
--
作者：
Bhattacharjee, Subrata;Simsek, Aslihan;Ferkul, Paul
反流火焰传播的三种形式——辐射、热和动力形式——是众所周知的。对于热薄燃料，扩散速率与热态中相反的流速无关。在动力学区，它随着流速的增加而减小，导致吹离消光。在主要发生在无浮力的微重力环境中的辐射状态下，传播速率随着流速的降低而降低，除非氧含量非常高，否则会导致辐射消光。最近在国际空间站上进行的一项实验中，人们在一个流动隧道中点燃了PMMA薄片，其反向流动的变化幅度很大。这是第一次在一组实验中捕捉到所有三种火焰蔓延状态。通过数字视频处理得到瞬时传播速率，并与计算模型比较了三种状态下火焰形状演变的瞬时传播速率。在辐射和热状态下的传播速率也与现有的热和辐射状态下的火焰传播理论进行了比较，得出了显著的定性一致。(C)燃烧研究所2016。Elsevier Inc.出版。
The three regimes of opposed-flow flame spread - radiative, thermal, and kinetic regimes - are well known. For thermally thin fuels, the spread rate is independent of opposing flow velocity in the thermal regime. It decreases with an increase in the flow velocity in the kinetic regime, leading to blow off extinction. In the radiative regime which occurs mostly in a buoyancy-free environment of microgravity, the spread rate decreases with a decrease in flow velocity leading to radiative extinction unless the oxygen level is very high. In a recent experiment aboard the International Space Station, thin sheets of PMMA were ignited in a flow tunnel with the opposing flow varying over a wide range. All three regimes of flame spread were captured in a single set of experiments for the first time. Instantaneous spread rates were obtained from digital video processing and compared with a computational model in all three regimes along with the evolution of flame shapes. Spread rates in the radiative and thermal regimes are also compared with existing theories of flame spread in the thermal and the radiative regime producing remarkable qualitative agreement. (C) 2016 by The Combustion Institute. Published by Elsevier Inc.