Turbulent flame propagation of polymethylmethacrylate particle clouds in an O2/N2 atmosphere
Turbulent flame propagation of polymethylmethacrylate particle clouds in an O2/N2 atmosphere
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DOI：
10.1016/j.combustflame.2021.111616
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发表时间：
2021-12
影响因子：
4.4
通讯作者：
Yu Xia;Nozomu Hashimoto;O. Fujita
中科院分区：
文献类型：
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作者：
Yu Xia;Nozomu Hashimoto;O. Fujita
固体颗粒云的燃烧在许多工程领域有着广泛的应用。然而，描述湍流火焰传播行为和固体颗粒云燃烧机理的实验数据仍然有限。在这项工作中，聚甲基丙烯酸甲酯（PMMA）颗粒云的燃烧研究采用了独特的风扇搅拌定容室。对于准单分散颗粒云，火焰传播速度随着湍流强度的增加和准单分散颗粒尺寸的减小而增加。然而，颗粒浓度对火焰传播速度的影响很小，这是唯一的湍流场。PMMA颗粒云的研究结果与煤颗粒云的研究结果一致，表明焦炭颗粒的非均相燃烧对固体颗粒云的湍流火焰传播速度影响不大。此外，两种类型的准单分散颗粒混合，以研究小和大（多分散）颗粒之间的相互作用如何影响湍流火焰传播。研究发现，湍流火焰传播速度与小颗粒质量比呈非线性关系（J型曲线）。湍流火焰传播速度随小颗粒质量比的减小而略有增加，随小颗粒质量比的增大而急剧增加。增加湍流强度和减小一次颗粒（大颗粒）粒径可以使湍流度急剧上升的起始点提前。这些独特的功能解释了作者提出的多分散颗粒间相互作用的机制。在湍流多分散颗粒云燃烧过程中，湍流流场中颗粒间的团聚和团聚体的破碎影响湍流火焰的传播。据我们所知，这是第一个报告的基本球形湍流火焰传播现象和固体颗粒云燃烧的机制，考虑多分散颗粒间的相互作用。
The combustion of solid particle clouds is extensively used in many engineering areas. However, experimental data describing the turbulent flame propagation behavior and the combustion mechanism of solid particle clouds have remained limited. In this work, the combustion of polymethylmethacrylate (PMMA) particle clouds was studied by employing a unique fan-stirred constant-volume chamber. For the quasi-monodispersed particle clouds, the flame propagation velocity increased with the increase in the turbulence intensity and the decrease in the quasi-monodispersed particle size. However, the particle concentration had little effect on the flame propagation velocity, which is unique in a turbulent flow field. The consistency of the results between the current study of PMMA particle clouds and the previous study for coal particle clouds showed that the heterogeneous combustion of char particles had little effect on the turbulent flame propagation velocity of the solid particle clouds. Further, two types of quasi-monodispersed particles were mixed to study how the interactions between small and large (polydispersed) particles affect turbulent flame propagation. We found that the turbulent flame propagation velocity had a nonlinear relationship with the mass ratio of small particles (J-shaped curve). The turbulent flame propagation velocity slightly increased with low mass ratio of small particles, while it sharply increased with high mass ratio of small particles. Increasing the turbulence intensity and decreasing the primary particle (large particle) size can advance the starting point of the sharp increase. These unique features were explained by a mechanism considering the polydispersed interparticle interaction proposed by the authors. In the combustion of turbulent polydispersed particle clouds, the particle–particle agglomeration and the agglomeration break-up in the turbulent flow field affect turbulent flame propagation. To the best of our knowledge, this is the first report on the fundamental spherical turbulent flame propagation phenomenon and the mechanism of solid particle cloud combustion considering the polydispersed interparticle interactions.