Three Dimensional DEM/CFD Analysis of Segregation During Silo Filling with Binary Mixtures of Different Particle Sizes

2012 ◽  
pp. 165-174
Author(s):  
C.-Y. Wu ◽  
Y. Guo
Keyword(s):  
Binary Mixtures ◽  
Three Dimensional ◽  
Particle Sizes ◽  
Cfd Analysis

Three-dimensional pore characteristics and permeability properties of calcareous sand with different particle sizes

2021 ◽  
Vol 80 (3) ◽  
pp. 2659-2670
Author(s):  
Zhihan Fan ◽  
Cong Hu ◽  
Qianlin Zhu ◽  
Yonggang Jia ◽  
Dianjun Zuo ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Particle Sizes ◽  
Calcareous Sand ◽  
Pore Characteristics

scholarly journals CFD Analysis of a Water Vaporization Process in a Three-Dimensional Spouted Bed for Flue Gas Desulfurization

ACS Omega ◽  
2021 ◽  
Vol 6 (4) ◽  
pp. 2759-2766
Author(s):  
Jiali Du ◽  
Zhiquan Hui ◽  
Feng Wu ◽  
Yuan Yan ◽  
Kai Yue ◽  
...  
Keyword(s):  
Flue Gas ◽  
Three Dimensional ◽  
Flue Gas Desulfurization ◽  
Cfd Analysis ◽  
Spouted Bed ◽  
Vaporization Process ◽  
Water Vaporization

An Automated CFD Design and Analysis Tool for Inlet-Bleed Systems

1998 ◽  
Author(s):  
Tom I-P. Shih ◽  
Yu-Liang Lin ◽  
Andrew J. Flores ◽  
Mark A. Stephens ◽  
Mark J. Rimlinger ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Three Dimensional ◽  
Incident Shock ◽  
Navier Stokes ◽  
Oblique Shock Wave ◽  
Design Parameters ◽  
Analysis Tool ◽  
Cfd Analysis ◽  
Circular Holes ◽  
Embedded Grids

Abstract A pre-processor was developed to assist CFD experts and non-experts in performing steady, three-dimensional Navier-Stokes analysis of a class of inlet-bleed problems involving oblique shock-wave/ boundary-layer interactions on a flat plate with bleed into a plenum through rows of circular holes. With this pre-processor, once geometry (e.g., hole dimensions and arrangement) and flow conditions (e.g., Mach number, boundary-layer thickness, incident shock location) are inputted, it will automatically generate every file needed to perform a CFD analysis from the grid system to initial and boundary conditions. This is accomplished by accessing a knowledge base established by experts who understand both CFD and the class of problems being analyzed. For experts in CFD, this tool greatly reduces the amount of time and effort needed to setup a problem for CFD analysis. It also provides experts with knobs to make changes to the setup if desired. For non-experts in CFD, this tool enables reliable and correct usage of CFD. A typical session on a workstation from data input to the generation of all files needed to perform a CFD analysis involves less than ten minutes. This pre-processor, referred to as AUTOMAT-V2, is an improved version of a code called AUTOMAT. Improvements made include: (1) multi-block structured grids can be patched in addition to being overlapped; (2) embedded grids can be introduced near bleed holes to reduce the number of grid points/cells needed by a factor of up to four; (3) grid systems generated allow up to three levels of multigrid; (4) CFL3D is supported in addition to OVERFLOW, two well-known and highly regarded Navier-Stokes solvers developed at NASA’s Langley and Ames Research Centers; (5) all files needed to run RONNIE for patched grids and MAGGIE for overlapped grids are also generated; and (6) more design parameters can be investigated including the study of micro bleed and effects of flow/hole misalignments.

scholarly journals Modeling the dynamical sinking of biogenic particles in oceanic flow

2017 ◽  
Vol 24 (2) ◽  
pp. 293-305 ◽  
Author(s):  
Pedro Monroy ◽  
Emilio Hernández-García ◽  
Vincent Rossi ◽  
Cristóbal López
Keyword(s):  
Three Dimensional ◽  
Finite Size ◽  
Equation Of Motion ◽  
Particle Dynamics ◽  
Particle Sizes ◽  
Small Particles ◽  
Physical Processes ◽  
Mesoscale Simulation ◽  
Sinking Particles ◽  
Theoretical Results

Abstract. We study the problem of sinking particles in a realistic oceanic flow, with major energetic structures in the mesoscale, focussing on the range of particle sizes and densities appropriate for marine biogenic particles. Our aim is to evaluate the relevance of theoretical results of finite size particle dynamics in their applications in the oceanographic context. By using a simplified equation of motion of small particles in a mesoscale simulation of the oceanic velocity field, we estimate the influence of physical processes such as the Coriolis force and the inertia of the particles, and we conclude that they represent negligible corrections to the most important terms, which are passive motion with the velocity of the flow, and a constant added vertical velocity due to gravity. Even if within this approximation three-dimensional clustering of particles can not occur, two-dimensional cuts or projections of the evolving three-dimensional density can display inhomogeneities similar to the ones observed in sinking ocean particles.

CFD Analysis of Cross Flow in Rod Bundles Under Rolling Motion

2016 ◽  
Author(s):  
Di Liu ◽  
Wenxi Tian ◽  
Suizheng Qiu ◽  
G. H. Su
Keyword(s):  
Flow Behavior ◽  
Three Dimensional ◽  
Cross Flow ◽  
Reynolds Stress Model ◽  
Momentum Equation ◽  
Rolling Motion ◽  
Cfd Analysis ◽  
Rod Bundles ◽  
Rolling Velocity ◽  
Dimensional Simulation

A CFD analysis of cross flow in rod bundles in rolling motion was performed to investigate the effect of rolling motion on the flow behavior between the subchannels. The rolling motion was assumed as a sinusoid. The additional forces due to the rolling motion including azimuthal force, centrifugal force and coriolis force were added into the source term in the momentum equation. A transient three dimensional simulation of square rod bundles model was performed in various rolling conditions. In order to precisely predict secondary flow patterns in rod bundles, Reynolds Stress Model was selected as the turbulent model. Effect of various rolling parameters such as rolling velocity and amplitude on the cross mixing was investigated. The results show that cross flow is strongly affected by the rolling motion. The local cross flow field in rolling motion was showed in detail. Also, the mixing coefficients based on CFD results were calculated. Empirical correlations of turbulent mixing were modified to consider the effect of rolling conditions, which can be used in the traditional subchannel thermal hydraulic code.

About the Thermal Hydraulic Analysis Part of a Coupled Study on a Thorium-Fueled SCWR Concept

2020 ◽  
Vol 6 (3) ◽  
Author(s):  
Attila Kiss ◽  
Béla Hegyesi ◽  
Patrik Richárd Ujváry ◽  
András Szabolcs Ványi ◽  
Gyula Csom
Keyword(s):  
Fuel Cycle ◽  
Three Dimensional ◽  
Spectral Shift ◽  
Average Density ◽  
Study Phase ◽  
Cfd Analysis ◽  
Axial Distribution ◽  
Cfd Models ◽  
Water Reactors ◽  
Uranium Plutonium

Abstract Inherently poorer moderation in supercritical water-cooled reactors (SCWRs) due to average density lower than in light water reactors and the resulted spectral shift can be useful when we apply thorium fuel-cycle instead of uranium–plutonium one, according to an ongoing study in Budapest University of Technology and Economics (BME) Institute of Nuclear Techniques (NTI). Upon this conclusion, a thorium-fueled SCWR design (Th-SCWR) has been proposed by BME NTI. In the current feasibility study phase, detailed three-dimensional (3D) computational fluid dynamics (CFD) calculations with novel neutronics analysis were coupled and conducted separately. Neutronics calculations provided the distribution of heat source, while the CFD analysis gave back axial distribution of coolant density (this iteration was repeated until an acceptable convergence). This paper presents the CFD analysis on thermal hydraulics of the initial design (two CFD models without any spacer device and one model with wrapped wire spacer) of Th-SCWR fuel assembly. As results of the preliminary design of Th-SCWR cladding wall, coolant and fuel temperatures have been determined; the flow field with and without spacer device has been showed, and the application of wrapped wire spacer has been proposed.

Bowl-Type Diffusers for Low Specific-Speed Pumps: An Industrial Application

2006 ◽  
Author(s):  
Paolo Boncinelli ◽  
Roberto Biagi ◽  
Antonio Focacci ◽  
Umberto Corradini ◽  
Andrea Arnone ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Cfd Analysis ◽  
Aerodynamic Design ◽  
Three Dimensional Flow ◽  
Aerodynamic Efficiency ◽  
Recovery Capacity ◽  
Critical Problems ◽  
Low Specific Speed ◽  
Specific Speed ◽  
Numerical Solver

In this paper, the aerodynamic design of a bowl–type diffuser for a low specific–speed pump is presented and described in detail. The main goal was to achieve an optimal configuration in terms of diffuser recovery capacity and stage aerodynamic efficiency, while satisfying severe constraints concerning stage size and multistage feasibility. Both geometrical parametrization tools and a fully–viscous three–dimensional numerical solver were exploited in the design process. The geometrical parameterization allowed one to control and modify the geometry of the component by changing a limited number of parameters. CFD analysis was exploited to assess the effectiveness of the geometrical modifications on the performance, and to identify critical problems. A number of aerodynamic ID coefficients with simple physical meanings were also introduced and used as a support to the design to synthesize the main feature of the strongly three–dimensional flow evolving in the component. As a result, a new stage configuration was developed according to the imposed constraints, whose performance is at the same level as standard pumps of the same class.

The Effect of Microstructural Morphologies on the Effective Electromechanical Properties of Piezoelectric Particle Composites

2012 ◽  
Author(s):  
Vahid Tajeddini ◽  
Chien-hong Lin ◽  
Anastasia Muliana ◽  
Martin Lévesque
Keyword(s):  
Mechanical Properties ◽  
Elastic Moduli ◽  
Volume Fraction ◽  
Micromechanical Model ◽  
Three Dimensional ◽  
Particle Sizes ◽  
Reinforced Composites ◽  
Electromechanical Properties ◽  
Particle Volume ◽  
Self Consistent

This study introduces a micromechanical model that incorporates detailed microstructures for analyzing the effective electro-mechanical properties, such as piezoelectric and permittivity constants as well as elastic moduli, of piezoelectric particle reinforced composites. The studied composites consist of polarized spherical piezoelectric particles dispersed into a continuous and elastic polymeric matrix. A micromechanical model generated using three-dimensional (3D) continuum elements within a finite element (FE) framework. For each volume fraction (VF) of particles, realization with different particle sizes and arrangements were generated in order to represent microstructures of a particle composite. We examined the effects of microstructural morphologies, such as particle sizes and distributions, and particle volume fractions on the overall effective electro-mechanical properties of the active composites. The overall electro-mechanical properties determined from the present micromechanical model were compared to those generated using the Mori-Tanaka, self-consistent, and simplified unit-cell micromechanical models.

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