当前位置: X-MOL 学术Proc. Combust. Inst. › 论文详情
Our official English website, www.x-mol.net, welcomes your feedback! (Note: you will need to create a separate account there.)
Opposed-flow flame spread in a narrow channel: Prediction of flame spread velocity
Proceedings of the Combustion Institute ( IF 3.4 ) Pub Date : 2018-09-07 , DOI: 10.1016/j.proci.2018.08.017
Koshi Funashima , Ayaka Masuyama , Kazunori Kuwana , Genichiro Kushida

This paper presents results of experimental and numerical investigations of flame spread along a thin solid in an opposed oxygen flow in a narrow channel. Experiments are conducted at various oxygen flow speeds and gas-phase heights. For a low gas-phase height or a low oxygen flow speed, a large portion of solid is left unburned, and the burned region forms a finger-like pattern. It is noted that both the flame spread velocity and the fraction burned increase with an increase in the gas-phase height or oxygen flow speed. A simple, two-equation model is then developed to simulate the phenomenon. The original 3-D equations are reduced to 2-D forms, which are solved numerically. To simplify the model, it is assumed that the rate of solid pyrolysis is linearly proportional to that of gas-phase oxidation. A comparison between the numerical predictions and the experimental data, however, indicates that because of this assumption, prediction error tends to increase with increase in the gas-phase height or oxygen flow speed. Nevertheless, model predictions agree reasonably well with the experimental data, thus validating the assumptions of the model, at least qualitatively. A weakly nonlinear stability analysis is finally conducted to derive a relationship between the scaled flame spread velocity and a dimensionless parameter that combines the effects of material properties and experimental parameters such as the gas-phase height and oxygen flow speed. The presented numerical and experimental results support the stability analysis.



中文翻译:

对流火焰在狭窄通道中的蔓延:火焰蔓延速度的预测

本文介绍了在狭窄的通道中,在相反的氧气流中,火焰沿着稀薄的固体扩散的实验和数值研究结果。在各种氧气流速和气相高度下进行实验。对于低气相高度或低氧气流速,大部分固体不燃烧,并且燃烧的区域形成手指状图案。注意,随着气相高度或氧气流速的增加,火焰蔓延速度和燃烧分数均增加。然后,开发了一个简单的两方程模型来模拟该现象。原始的3-D方程式被简化为2-D形式,并通过数值求解。为了简化模型,假设固体热解速率与气相氧化速率成线性比例关系。然而,数值预测与实验数据之间的比较表明,由于该假设,预测误差倾向于随着气相高度或氧气流速的增加而增加。然而,模型预测与实验数据相当吻合,从而至少在质量上验证了模型的假设。最后进行了弱非线性稳定性分析,以得出缩放的火焰传播速度与无量纲参数之间的关系,该无量纲参数结合了材料性能和实验参数(如气相高度和氧气流速)的影响。给出的数值和实验结果支持稳定性分析。预测误差倾向于随着气相高度或氧气流速的增加而增加。然而,模型预测与实验数据相当吻合,从而至少在质量上验证了模型的假设。最后进行了弱非线性稳定性分析,以得出缩放的火焰传播速度与无量纲参数之间的关系,该无量纲参数结合了材料性能和实验参数(如气相高度和氧气流速)的影响。给出的数值和实验结果支持稳定性分析。预测误差倾向于随着气相高度或氧气流速的增加而增加。然而,模型预测与实验数据相当吻合,从而至少在质量上验证了模型的假设。最后进行了弱非线性稳定性分析,以得出缩放的火焰传播速度与无量纲参数之间的关系,该无量纲参数结合了材料性能和实验参数(如气相高度和氧气流速)的影响。给出的数值和实验结果支持稳定性分析。最后进行了弱非线性稳定性分析,以得出缩放的火焰传播速度与无量纲参数之间的关系,该无量纲参数结合了材料性能和实验参数(如气相高度和氧气流速)的影响。给出的数值和实验结果支持稳定性分析。最后进行了弱非线性稳定性分析,以得出缩放的火焰传播速度与无量纲参数之间的关系,该无量纲参数结合了材料性能和实验参数(如气相高度和氧气流速)的影响。给出的数值和实验结果支持稳定性分析。

更新日期:2018-09-07
down
wechat
bug