In situ study of aggregation of soot particles in an acetylene flame by small-angle x-ray scattering
In situ study of aggregation of soot particles in an acetylene flame by small-angle x-ray scattering
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DOI：
10.1063/1.2740341
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发表时间：
2007-06
影响因子：
3.2
通讯作者：
M. Sztucki;T. Narayanan;G. Beaucage
中科院分区：
文献类型：
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作者：
M. Sztucki;T. Narayanan;G. Beaucage
用同步辐射小角X射线散射法研究了乙炔火焰中碳烟颗粒的形核和长大过程。用统一的散射函数分析了10−3 nm−1⩽Q⩽0.5 nm−1等宽散射矢量(Q)范围内的散射强度，包括初级粒子、聚集体和凝聚体的三个结构能级.一次粒子具有致密的形貌，其末端回转半径(Rg)约为27 nm，其生长动力学与形核生长过程一致。集合体Rg的演化表现为扩散限制生长机制，形成分维(DF)≈2和Rg∼250 nm。尽管碳烟的产量随着流量的增加而显著增加，但聚集动力学、末端Rg和Df几乎保持不变。研究中使用的流量扩展到了碳烟的气凝胶区域，但聚集动力学与非凝聚情况相似。用同步加速器小角X射线散射研究了乙炔火焰中碳烟颗粒的成核和生长。用统一的散射函数分析了10−3 nm−1⩽Q⩽0.5 nm−1等宽散射矢量(Q)范围内的散射强度，包括初级粒子、聚集体和凝聚体的三个结构能级.一次粒子具有致密的形貌，其末端回转半径(Rg)约为27 nm，其生长动力学与形核生长过程一致。集合体Rg的演化表现为扩散限制生长机制，形成分维(DF)≈2和Rg∼250 nm。尽管碳烟的产量随着流量的增加而显著增加，但聚集动力学、末端Rg和Df几乎保持不变。本研究中使用的流量扩展到了烟尘的气凝胶区域，但发现聚集动力学与非格林情况相似。
The nucleation and growth of soot particles in an acetylene flame were investigated by synchrotron small-angle x-ray scattering. The scattered intensity spanning over a wide scattering vector (q) range, 10−3nm−1⩽q⩽0.5nm−1, was analyzed using the unified scattering function involving up to three structural levels corresponding to primary particles, aggregates, and agglomerates. The primary particles have a compact morphology with a terminal radius of gyration (Rg) of about 27nm and their growth dynamics is consistent with the nucleation and growth process. The evolution of aggregate Rg reveals a diffusion limited growth mechanism resulting in a fractal dimension (df)≈2 and Rg∼250nm. Although the production of soot dramatically increases with the flow rate, the aggregation dynamics, terminal Rg, and df remain nearly the same. The flow rate used in this study extended to the regime of aerogelation of soot but the aggregation dynamics is found to be similar to the nongelling case.The nucleation and growth of soot particles in an acetylene flame were investigated by synchrotron small-angle x-ray scattering. The scattered intensity spanning over a wide scattering vector (q) range, 10−3nm−1⩽q⩽0.5nm−1, was analyzed using the unified scattering function involving up to three structural levels corresponding to primary particles, aggregates, and agglomerates. The primary particles have a compact morphology with a terminal radius of gyration (Rg) of about 27nm and their growth dynamics is consistent with the nucleation and growth process. The evolution of aggregate Rg reveals a diffusion limited growth mechanism resulting in a fractal dimension (df)≈2 and Rg∼250nm. Although the production of soot dramatically increases with the flow rate, the aggregation dynamics, terminal Rg, and df remain nearly the same. The flow rate used in this study extended to the regime of aerogelation of soot but the aggregation dynamics is found to be similar to the nongelling case.