Meso-scale statistical properties of gas-solid flow—a direct numerical simulation (DNS) study

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• 作者：Xiaowen Liu ; Limin Wang and Wei Ge
• 刊名：AIChE Journal
• 出版年：2017
• 出版时间：January 2017
• 年：2017
• 卷：63
• 期：1
• 页码：3-14
• 全文大小：929K
• ISSN：1547-5905

文摘

Statistical properties of particles in heterogeneous gas–solid flow were numerically investigated based on the results of a three-dimensional large-scale direct numerical simulation (DNS). Strong scale-dependence and local non-equilibrium of these properties, especially the particle fluctuating velocity (PFV) or granular temperature, were observed to be related to the effect of meso-scale structures formed by the compromise in competition between fluid and particle dominated mechanisms. To quantify such effects, the heterogeneous structures were partitioned into a gas-rich dilute phase and a solid-rich dense phase according to the particle-scale voidage defined through the Voronoi tessellation. Non-equilibrium features, such as the deviation of PFV from Gaussian distribution and anisotropy, were found even in phase-specific properties. A new distribution function for the PFV well characterizing these features was obtained by fitting the DNS results, which takes a typical bi-disperse mode, with phase-specific granular temperatures. The implications of these findings to the kinetic theory of granular flow and traditional continuum models of gas–solid flow were also discussed.