Particle-Cloud Drag Force in Dilute Particle Systems: Discrete Element Method versus Eulerian Simulations

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• 作者：Payman Jalali ; Markku Nikku ; Timo Hypp盲nen
• 刊名：Industrial & Engineering Chemistry Research
• 出版年：2013
• 出版时间：March 20, 2013
• 年：2013
• 卷：52
• 期：11
• 页码：4342-4350
• 全文大小：443K
• 年卷期：v.52,no.11(March 20, 2013)
• ISSN：1520-5045

文摘

The discrete element method (DEM) is utilized to calculate the drag force on big spherical objects exerted by the cloud of small particles as they are subjected to an initial relative velocity. The drag force is calculated as the average over single collisions within a certain time interval. Then it is comparable to the calculated values obtained from Eulerian simulations, which are performed on the same particulate system by keeping the big spherical objects in discrete form and turning the cloud of small particles into a continuum phase. The DEM simulations indicate that the average drag force on a big particle in a cluster is lower than that on a single big particle. The decrease in drag force is even larger when the big particles in the cluster are arranged in an ordered configuration such as a simple cubic array. In Eulerian simulations, it is found that the model for kinetic viscosity plays an influential role in the calculated drag force. The two models known as Syamlal鈥揙鈥橞rian and Gidaspow models for kinetic viscosity are employed. Considering the DEM simulation results as the reference cases, it is shown that the Gidaspow model is suitable for the clusters of big particles, while the Syamlal鈥揙鈥橞rian model can reproduce the single big particle motion in a cloud precisely. It is discussed how the distribution of shear stress over the surface of particles in Eulerian simulations may explain the observed differences.