Applications of Computational Fluid Dynamics (CFD) Tools for Gravity Concentrators in Coal Preparation

2007 ◽  
Vol 2 (1) ◽  
Author(s):  
Y. K. Xia
Keyword(s):  
Multiphase Flows ◽  
Coupling Effect ◽  
Numerical Models ◽  
Dense Medium ◽  
Hindered Settling ◽  
Heavy Medium ◽  
Computational Fluid Dynamics Cfd ◽  
Dimensional Simulation ◽  
Dense Medium Cyclone ◽  
Lagrange Approach

Extensive progress has been made in using CFD tool in the simulation of multiphase flows in some gravity concentrators. Several case studies for calculation of multiphase flows by different numerical models in spiral, dense medium cyclone, water only cyclones, hindered-settling bed separator, heavy medium vessel and jig are reviewed. The Euler-Lagrange approach in calculation of the particle movement and particle-liquid coupling effect are also discussed. The limitation of Euler-Euler models in the treatment of the particles with a size distribution, and disadvantages of discrete element method (DEM) in description of the jigging processes will be presented. The successful two-dimensional simulation of the hindered-settling bed separator, heavy medium vessel and jig by Euler-Lagrange approach is also addressed.

A generalized settling approach in the numerical modeling of sedimentation tanks

1998 ◽  
Vol 38 (3) ◽  
pp. 95-102 ◽  
Author(s):  
G. Mazzolani ◽  
F. Pirozzi ◽  
G. d'Antonoi
Keyword(s):  
Transport Model ◽  
Numerical Models ◽  
Removal Rate ◽  
Total Concentration ◽  
Suspended Solid ◽  
Primary Concern ◽  
High Concentration ◽  
Hindered Settling ◽  
Low Concentration ◽  
Solid Distribution

Numerical models for the prediction of turbulent flow field and suspended solid distribution in sedimentation tanks are characterized by refined modeling of hydrodynamics, but apparently weak modeling of settling properties of suspensions. It is known that sedimentation tanks typically treat highly heterodisperse suspensions, whose concentrations range from relatively high to low values. However, settling is modeled either by considering one or more particle classes of different settling velocity, without accounting for hindered settling conditions, or by treating the suspension as monodisperse, even in regions of low concentration. A new generalized settling model is proposed to account for both discrete settling conditions in low concentration regions of the tanks and hindered settling conditions in high concentration regions. Settling velocities of heterodisperse suspensions are then determined as a function of particle velocities in isolation and their total concentration. The settling model is used in the framework of a transport model for the simulation of hydrodynamics and solid distribution in a rectangular sedimentation tank. Results show that solid distribution is mainly affected by particle interactions in the inlet region and by settling properties of individual particles in the outlet region. Comparison of the proposed settling model with other settling models suggests that a generalized approach of the modeling of settling properties of suspensions is a primary concern to obtain reliable predictions of the removal rate.

scholarly journals Medium Density Control for Coal Washing Dense Medium Cyclone Circuits

2015 ◽  
Vol 23 (3) ◽  
pp. 1117-1122 ◽  
Author(s):  
Lijun Zhang ◽  
Xiaohua Xia ◽  
Jiangfeng Zhang
Keyword(s):  
Dense Medium ◽  
Medium Density ◽  
Density Control ◽  
Dense Medium Cyclone

Hydrodynamic Interaction Forces and Moments Prediction Methodology for the Ship Behavior Prediction During the Overtaking Maneuver

2015 ◽  
Author(s):  
Dmitry V. Nikushchenko ◽  
Anastasia A. Zubova
Keyword(s):  
Turbulence Modeling ◽  
Numerical Models ◽  
Wake Flow ◽  
Behavior Prediction ◽  
Ship Wake ◽  
Theoretical Investigations ◽  
Transverse Distance ◽  
Computational Fluid Dynamics Cfd ◽  
The Mathematical Model ◽  
Ship Behavior

Provided within current research extensive numerical and theoretical investigations include real maneuvering condition cases when ship-to-ship interaction phenomena play a significant role. General methodology for hydrodynamic forces and moments’ results analysis and further application within the mathematical model of marine simulators is implemented. Real conditions cases include: ship wake flow interaction with the overtaking ship; interaction between ships; speeds and transverse distance variations. Numerical investigations are carried out with the use of Computational Fluid Dynamics (CFD) methods; analysis of numerical models is completed based on the CFD codes used widely. A significant part of research is devoted to the turbulence modeling focused on flow specifics.

The effect of materials and design on the reliability of through-glass vias for 2.5 D integrated circuits: a numerical study

2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Omar Ahmed ◽  
Chukwudi Okoro ◽  
Scott Pollard ◽  
Tengfei Jiang
Keyword(s):  
Integrated Circuits ◽  
Buffer Layer ◽  
Coupling Effect ◽  
Numerical Study ◽  
Numerical Models ◽  
Thermal Strain ◽  
Content Type ◽  
Mismatch Strain ◽  
Pitch Distance ◽  
Stress Buffer

PurposeThis study aims to investigate the factors responsible for substrate cracking reliability problem in through-glass vias (TGVs), which are critical components for glass-based 2.5 D integration.Design/methodology/approachNumerical models were used to examine the driving force for substrate cracking in glass interposers due to stress coupling during heating. An analytical solution was used to demonstrate how the energy release rate (ERR) for the glass substrate cracking is affected by the via design and the mismatch in thermal strain. Then, the numerical models were implemented to investigate the design factors effects, such as the pitch distance, via diameter, via pattern, via design, effect from a stress buffer layer and the interposer materials selection on the susceptibility to substrate cracking.FindingsERR for substrate cracking was found to be directly proportional to the via diameter and the thermal mismatch strain. When a via pattern is implemented for high-density integration, a coupling in the stress fields was identified. This coupling effect was found to depend on the pitch distance, the position of the vias, and the via arrangement, suggesting a via pattern-dependent reliability behavior for glass interposers. Changing the design of the via to an annular shape or a substrate-cored via was found to be a promising approach to reduce the susceptibility to substrate cracking compared to a fully filled solid via. Also, the use of a stress buffer layer, an encouraging design prospect presented for the first time for TGVs in this study, was found to significantly reduce cracking. Finally, alternative via and substrate materials showed lower tendency for substrate cracking, indicating that the reliability of glass interposers can be further enhanced with the implementation of such new materials.Originality/valueThis study signifies the first attempt to comprehensively evaluate the susceptibility to crack formation in glass interposers during heating. Therefore, this study provides new perspectives on how to achieve a significant potential reliability improvement for TGVs.

Effect of coaxial electromagnetic field on separation density of dense-medium cyclone

2019 ◽  
Vol 138 ◽  
pp. 188-194
Author(s):  
Cheng-an Zhang ◽  
Zhang-lei Zhu ◽  
Guo-yuan Gao ◽  
Pan-pan Fan ◽  
Min-qiang Fan
Keyword(s):  
Electromagnetic Field ◽  
Dense Medium ◽  
Separation Density ◽  
Dense Medium Cyclone

An Experimental Assessment of Numerical Predictive Accuracy for Electronic Component Heat Transfer in Forced Convection—Part II: Results and Discussion

2003 ◽  
Vol 125 (1) ◽  
pp. 76-83 ◽  
Author(s):  
Peter J. Rodgers ◽  
Vale´rie C. Eveloy ◽  
Mark R. Davies
Keyword(s):  
Heat Transfer ◽  
Forced Convection ◽  
Printed Circuit Board ◽  
Predictive Accuracy ◽  
Numerical Models ◽  
Circuit Board ◽  
Junction Temperature ◽  
Electrical Performance ◽  
Test Cases ◽  
Computational Fluid Dynamics Cfd

Numerical predictive accuracy is assessed for component-printed circuit board (PCB) heat transfer in forced convection using a widely used computational fluid dynamics (CFD) software. In Part I of this paper, the benchmark test cases, experimental methods and numerical models were described. Component junction temperature prediction accuracy for the populated board case is typically within ±5°C or ±10%, which would not be sufficient for temperature predictions to be used as boundary conditions for subsequent reliability and electrical performance analyses. Neither the laminar or turbulent flow model resolve the complete flow field, suggesting the need for a turbulence model capable of modeling transition. The full complexity of component thermal interaction is shown not to be fully captured.

Studies on a Vorsyl separator as an alternate for a dense medium cyclone

1998 ◽  
Vol 53 (1-2) ◽  
pp. 49-57 ◽  
Author(s):  
T.C. Rao ◽  
J.P. Barnwal ◽  
B. Govindarajan
Keyword(s):  
Dense Medium ◽  
Dense Medium Cyclone
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