CFD Simulation on Solid Suspension with Continuous Operation

2011 ◽  
Vol 233-235 ◽  
pp. 1177-1183 ◽  
Author(s):  
Chang Shu ◽  
Xue Kui Wang ◽  
Zuo Liang Sha
Keyword(s):  
Particle Size ◽  
Concentration Distribution ◽  
Particle Distribution ◽  
Cfd Simulation ◽  
Continuous Operation ◽  
Multiphase Model ◽  
Solid Concentration ◽  
Product Removal ◽  
Mixing Intensity ◽  
Solid Suspension

The aim of this work is to investigate the solid concentration distribution in a DTB crystallizer under continuous operation. The effects of mixing intensity and product removal location on solid concentration distribution in the crystallizer were studied by CFD simulation with multiphase model for different sizes of particles. The results showed that the particle distribution in a crystallizer was dependent on the size of the particles and the mixing intensity. However, the product removal location did not significantly affect particle size distribution in the crystallizer under the studied conditions.

Particle Distribution Statistics in CFD Modeling of Polymer Processing

2014 ◽  
Vol 704 ◽  
pp. 12-16
Author(s):  
Abbas Rahimi ◽  
Andy Cordonier ◽  
Abhilash J. Chandy
Keyword(s):  
Particle Size ◽  
Conditional Distribution ◽  
Particle Distribution ◽  
Cfd Simulation ◽  
Strong Dependence ◽  
Polymer Processing ◽  
Cfd Modeling ◽  
Dependence Structure ◽  
Entropy Theory ◽  
Different Temperatures

This study presents statistical analysis of particle size distribution from a CFD simulation of polymer devolatilization in contactor, that uses superheated steam to isolate the polymers. This is accomplished by estimating marginal distributions of particle size and temperature using maximum Shannon Entropy theory and capturing their dependence structure by employing Copula thoery. The Copula-based conditional distribution of particles at different temperatures reveals the strong dependence of particle size to heat exchange and corresponding temperature.

scholarly journals CFD simulation of solids suspension in stirred tanks: Review

2010 ◽  
Vol 64 (5) ◽  
pp. 365-374 ◽  
Author(s):  
Aoyi Ochieng ◽  
Mrice Onyango
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Concentration Distribution ◽  
Cfd Simulation ◽  
Fluid Dynamic ◽  
Cfd Modeling ◽  
Small Scale ◽  
Stirred Tanks ◽  
Solids Concentration

Many chemical reactions are carried out using stirred tanks, and the efficiency of such systems depends on the quality of mixing, which has been a subject of research for many years. For solid-liquid mixing, traditionally the research efforts were geared towards determining mixing features such as off-bottom solid suspension using experimental techniques. In a few studies that focused on the determination of solids concentration distribution, some methods that have been used have not been accurate enough to account for some small scale flow mal-distribution such as the existence of dead zones. The present review shows that computational fluid dynamic (CFD) techniques can be used to simulate mixing features such as solids off-bottom suspension, solids concentration and particle size distribution and cloud height. Information on the effects of particle size and particle size distribution on the solids concentration distribution is still scarce. Advancement of the CFD modeling is towards coupling the physical and kinetic data to capture mixing and reaction at meso- and micro-scales. Solids residence time distribution is important for the design; however, the current CFD models do not predict this parameter. Some advances have been made in recent years to apply CFD simulation to systems that involve fermentation and anaerobic processes. In these systems, complex interaction between the biochemical process and the hydrodynamics is still not well understood. This is one of the areas that still need more attention.

CFD Simulation Research on Flow Characteristics of Fluidized Beds

2014 ◽  
Vol 881-883 ◽  
pp. 1809-1813
Author(s):  
Li Ning Han ◽  
Lu Min Wang
Keyword(s):  
Particle Size ◽  
Pressure Drop ◽  
Fluidized Bed ◽  
Fluidized Beds ◽  
Particle Distribution ◽  
Cfd Simulation ◽  
Fluid Model ◽  
Flow Characteristics ◽  
Fluidization Velocity ◽  
Motion Characteristics

The Euler-Euler two-fluid model incorporating the kinetic theory of granular flow was applied to simulate the gas-solid flow in fluidized beds. The pressure drop, particle distribution and motion characteristics were studied in this paper. In order to investigate the effect of structure of the fluidized bed on flow characteristics, fluidized beds with different diameters and structures were applied. User defined functions (UDF) were applied to study the flow characteristics when the particle size and mass changed over time. The results showed that with the increase of particle size, higher minimum fluidization velocity was required, but lower pressure drop was obtained. For a certain fluidizing medium, the bed critical fluidization velocity depended only on the size and nature of the particles. The structure of a fluidized bed had an influence on the particle distribution and motion characteristics.

scholarly journals CFD Simulation of Solid Suspension for a Liquid–Solid Industrial Stirred Reactor

2021 ◽  
Vol 11 (12) ◽  
pp. 5705
Author(s):  
Adrian Stuparu ◽  
Romeo Susan-Resiga ◽  
Alin Bosioc
Keyword(s):  
Chemical Reaction ◽  
Cfd Simulation ◽  
Simulation Analysis ◽  
Solid Phase ◽  
Initial Conditions ◽  
Chemical Reactor ◽  
Liquid Mixtures ◽  
Multiphase Model ◽  
Chemical Product ◽  
Two Phase

The present study examines the possibility of using an industrial stirred chemical reactor, originally employed for liquid–liquid mixtures, for operating with two-phase liquid–solid suspensions. It is critical when obtaining a high-quality chemical product that the solid phase remains suspended in the liquid phase long enough that the chemical reaction takes place. The impeller was designed for the preparation of a chemical product with a prescribed composition. The present study aims at finding, using a numerical simulation analysis, if the performance of the original impeller is suitable for obtaining a new chemical product with a different composition. The Eulerian multiphase model was employed along with the renormalization (RNG) k-ε turbulence model to simulate liquid–solid flow with a free surface in a stirred tank. A sliding-mesh approach was used to model the impeller rotation with the commercial CFD code, FLUENT. The results obtained underline that 25% to 40% of the solid phase is sedimented on the lower part of the reactor, depending on the initial conditions. It results that the impeller does not perform as needed; hence, the suspension time of the solid phase is not long enough for the chemical reaction to be properly completed.

Quantitative cross-sectional measurement of solid concentration distribution in slurries using a wire-mesh sensor

2015 ◽  
Vol 27 (1) ◽  
pp. 015301 ◽  
Author(s):  
Eduardo Nunes dos Santos ◽  
Eckhard Schleicher ◽  
Sebastian Reinecke ◽  
Uwe Hampel ◽  
Marco Jose Da Silva
Keyword(s):  
Concentration Distribution ◽  
Wire Mesh ◽  
Solid Concentration ◽  
Cross Sectional ◽  
Sectional Measurement

Green synthesis of submicron copper powder with narrow particle size distribution via a simple methanol thermal reduction

2021 ◽  
Author(s):  
Xiaoping Chen ◽  
Jiaqi Fu ◽  
Jiangang Li ◽  
Bohong Chen ◽  
Lei Yang ◽  
...  
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Green Synthesis ◽  
Size Distribution ◽  
Copper Powder ◽  
Reduction Method ◽  
Particle Distribution ◽  
Thermal Reduction ◽  
Narrow Particle Size Distribution

In this work, submicron copper powder with narrow particle distribution was synthesized via a simple methanol thermal reduction method without using any surfactants. Smaller copper powder with narrower particle size...

Informational Measures of the Shape of the Amoroso Distributions for the Research of Dispersed Materials

2021 ◽  
Vol 1031 ◽  
pp. 58-66
Author(s):  
Vitaly Polosin
Keyword(s):  
Particle Size ◽  
Distribution Function ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Applied Research ◽  
Particle Distribution ◽  
Size Distribution Function ◽  
Distribution Model ◽  
Information Uncertainty ◽  
Particle Size Distribution Function

For the particle size distribution function various forms of exponential models are used to construct models of the properties of dispersed substance. The most difficult stage of applied research is to determine the shape of the particle distribution model. For the particle size distribution function various forms of exponential models are used to construct models of the properties of dispersed substance. The most difficult stage of applied research is to determine the shape of the particle distribution model. The article proposes a uniform model for setting the interval of information uncertainty of non-symmetric particle size distributions. Based on the analysis of statistical and information uncertainty intervals, new shape coefficients of distribution models are constructed, these are the entropy coefficients for shifted and non shifted distributions of the Amoroso family. Graphics of dependence of entropy coefficients of non-symmetrical distributions show that distributions well-known are distinguish at small of the shapes parameters. Also it is illustrated for parameters of the form more than 2 that it is preferable to use the entropy coefficients for the unshifted distributions.The material contains also information measures for the well-known logarithmic normal distribution which is a limiting case of distribution Amorozo.

scholarly journals EFFECT OF GALLERIES ON THE WIND FLOW STRUCTURE AND POLLUTANT TRANSPORT WITHIN STREET CANYONS WITH OR WITHOUT FACADE ROUGHNESS ELEMENTS (BALCONIES)

2020 ◽  
Vol 7 (12) ◽  
pp. 45-59
Author(s):  
V. A. Karkoulias ◽  
P. E. Marazioti ◽  
D. P. Georgiou ◽  
E. A. Maraziotis
Keyword(s):  
Flow Field ◽  
Concentration Distribution ◽  
Cfd Simulation ◽  
Field Structure ◽  
Flow Structures ◽  
Street Canyons ◽  
Ansys Fluent ◽  
Roughness Elements ◽  
Computational Fluid Dynamics Cfd ◽  
The Vertical Distribution

This paper investigates how the structure of the flow field and the vertical distribution of the pollutant concentration near the wall facades of street canyons are affected by the presence of some elements such as street level galleries. Numerical results are presented for various gallery geometries in combination with facade roughness elements (balconies) for a canyon of an aspect ratio equal to h/w=2.33. The results were obtained by a Computational Fluid Dynamics (CFD) simulation employing the ANSYS-FLUENT suite that incorporated the k-e turbulent (RNG) model. The simulation generated several flow structures inside the canyon (mainly vortices), whose characteristic properties (e.g. number, strength and size) are discussed in terms of the effect of the galleries on the flow field structure and the roughness generated by the building façade balconies. The results indicate a significant influence on both the flow field structure and the mass concentration distribution of the polluting particles.

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