A CFD-DEM model is developed for chemical vapour deposition of silane in a fluidized bed reactor to investigate the effect of polydispersity on local phase dynamics, mass and heat transport, as well as the rate of Si deposition. Both gas-phase fines formation and heterogeneous deposition on the seed particle, as well as the scavenging effect for Si particle growth, are incorporated. The method is first validated against the experimentally measured Si deposition rate, percentage of fine production and minimum fluidisation velocity. Subsequently, the properties, primarily particle intermixing, fluidisation behaviour and bubble dynamics along with the deposition process, are analyzed for several polydisperse beds under various operating conditions. The effect of polydispersity of the bed on a fraction of the bubble size, dense phase expansion and interchange coefficient between various phases is thoroughly investigated to establish a correlation with reactor performance. The results show that broad-Gaussian particle size distribution (PSD) exhibits excellent improvement in fluidisation behaviour, resulting in a high deposition rate, and minimum formation of Si fines.

中文翻译：

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CFD-DEM 分析颗粒多分散性对硅烷热解过程中流化床反应器性能的影响

开发了用于流化床反应器中硅烷化学气相沉积的 CFD-DEM 模型，以研究多分散性对局部相动力学、质量和热传输以及硅沉积速率的影响。气相细粒的形成和种子颗粒上的异质沉积，以及硅颗粒生长的清除效应都被纳入其中。该方法首先根据实验测量的硅沉积速率、精细生产百分比和最小流化速度进行验证。随后，对不同操作条件下的多个多分散床的特性（主要是颗粒混合、流化行为和气泡动力学以及沉积过程）进行了分析。彻底研究了床的多分散性对气泡尺寸、致密相膨胀和各相之间的交换系数的影响，以建立与反应器性能的相关性。结果表明，宽高斯粒度分布 (PSD) 在流化行为方面表现出出色的改善，从而实现高沉积速率和最小化硅细粉的形成。