Comparison of three types of swirling generators in coarse particle pneumatic conveying using CFD-DEM simulation

The present investigation aims at developing a gas and particle flow model based on CFD-DEM coupling for three types of swirling generators. Grid and time size dependence tests were performed to validate the numerical model; the prediction ability of the model was confirmed through comparison with experimental data. Detailed studies of certain parameters (including the fluid pattern, swirling number and pressure drop) were based on the CFD method for the three-lobed, rifle and internal spiral vanes swirling generator pipelines. These studies were performed using dimensionless forms and numerical simulations. The peak regions of the axial velocity for the three-lobed and internal spiral vanes pipes have obvious asymmetrical patterns that rotate quasi-periodically downstream; the three-lobed pipe generates the largest swirl number and decays the fastest. In addition, quantitative calculations using the CFD-DEM coupling model, which include the particle distribution and the pneumatic conveying efficiency, suggest that the three-lobed swirling generator is suitable for the preliminary conveying stage and that the internal spiral structure in this work is a favorable option for swirling pneumatic conveying systems for coarse particles.

[1]  P. Cundall,et al.  A discrete numerical model for granular assemblies , 1979 .

[2]  Wiendelt Steenbergen,et al.  The rate of decay of swirl in turbulent pipe flow , 1998 .

[3]  M. P. Escudier,et al.  Observations and LDA measurements of confined turbulent vortex flow , 1980, Journal of Fluid Mechanics.

[4]  Asghar Molaei Dehkordi,et al.  Prediction of equilibrium mixing state in binary particle spouted beds: Effects of solids density and diameter differences, gas velocity, and bed aspect ratio , 2015 .

[5]  Hideto Yoshida,et al.  Three-dimensional simulation of air cyclone and particle separation by a revised-type cyclone , 1996 .

[6]  Bow-yaw Wang,et al.  CFD–DEM simulation of the gas–solid flow in a cyclone separator , 2011 .

[7]  M. Sommerfeld,et al.  Swirling, particle-laden flows through a pipe expansion , 1992 .

[8]  Hao Zhou,et al.  Numerical investigation of gas-particle flow in the primary air pipe of a low NOx swirl burner - The DEM-CFD method , 2015 .

[9]  Aibing Yu,et al.  Application of periodic boundary conditions to CFD-DEM simulation of gas–solid flow in pneumatic conveying , 2013 .

[10]  T. Shih,et al.  A new k-ϵ eddy viscosity model for high reynolds number turbulent flows , 1995 .

[11]  F. Durst,et al.  Turbulence measurements in a swirling pipe flow , 2006 .

[12]  Stefan Heinrich,et al.  DEM–CFD modeling of a fluidized bed spray granulator , 2011 .

[13]  J. Derksen,et al.  Two-Way Coupled Large-Eddy Simulations of the Gas-Solid Flow in Cyclone Separators , 2008 .

[14]  Mohammad Hassan Saidi,et al.  Boundary Layer Solution for the Turbulent Swirling Decay Flow Through a Fixed Pipe: SBR at the Inlet , 2003 .

[15]  Tatsuro Ariyama,et al.  Dynamic Analysis of Gas and Solid Flows in Blast Furnace with Shaft Gas Injection by Hybrid Model of DEM-CFD , 2011 .

[16]  Yuji Tomita,et al.  Particle velocity and concentration characteristics in a horizontal dilute swirling flow pneumatic conveying , 2000 .

[17]  Jack Legrand,et al.  Particle image velocimetry investigation of the flow-field of a 3D turbulent annular swirling decaying flow induced by means of a tangential inlet , 2000 .

[18]  A. H. Algifri,et al.  Prediction of the Decay Process in Turbulent Swirl Flow , 1987 .

[19]  Yuji Tomita,et al.  An Experimental Study of Swirling Flow Pneumatic Conveying System in a Horizontal Pipeline , 1996 .

[20]  Keizo Yabumoto,et al.  Spontaneous structures in three-dimensional bubbling gas-fluidized bed by parallel DEM–CFD coupling simulation , 2008 .

[21]  David Hargreaves,et al.  Numerical modelling of swirl flow induced by a three-lobed helical pipe , 2010 .

[22]  Jos Derksen,et al.  Simulations of confined turbulent vortex flow , 2005 .

[23]  David F. Fletcher,et al.  CFD simulation of precession in sudden pipe expansion flows with low inlet swirl , 2002 .

[24]  Matthias Kraume,et al.  DEM-CFD simulations of fixed bed reactors with small tube to particle diameter ratios , 2011 .

[25]  Yuji Tomita,et al.  Characteristics of Swirling Flow in a Circular Pipe , 1994 .

[26]  Ian Lowndes,et al.  An experimental investigation of pneumatic swirl flow induced by a three lobed helical pipe , 2009 .