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.

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.

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.

CFD Simulation of Large Dust Collection Cyclones Positioned Vertically in Staggered Downward Cascade Arrangement

2013 ◽  
Author(s):  
Eugen-Dan Cristea ◽  
Pierangelo Conti
Keyword(s):  
Cfd Simulation ◽  
Solid Phase ◽  
Phase Particle ◽  
High Mass ◽  
Cfd Modeling ◽  
Cement Kiln ◽  
Dust Collection ◽  
Dry Process ◽  
Cascade Arrangement ◽  
Simulation Results

Three dimensional, time dependent Euler-Euler simulation approach for numerical calculation of multiphase strongly swirling turbulent gas-heavy laden particulate flow in large industrial collection cyclones, positioned vertically, in staggered downward cascade arrangement has been performed. The multiphase flow was featured high mass loading. This paper specifically addresses a CFD modeling of a “suspension preheater”, typical equipment for dry process cement kiln. Big sized cyclone separator is a key component of this device. The simulation case study was developed in the frame of the commercial general-purpose code ANSYS-Fluent R13. In cyclone separators the swirling gas motion induces a centrifugal force on the solid particulate phase which is the driving force behind the separation process. The turbulence disperses the solid particulates and enhances the probability that particles are discharged, as reject. Both phenomena are related to solid phase particle size distribution (PSD) and flow pattern into the collection cyclones. The multiphase turbulence was modeled using the RSM Mixture Turbulence Model. The simulation results were validated against industrial measurements carried out on an industrial suspension preheater, in the frame of heat and mass balance of cement kiln energy audit. The numerical simulation results were found in reasonable agreement with the collected industrial measurements. This CFD simulation represents a powerful engineering tool on behalf of the cement process engineer either for new cutting-edge design or for performance verification of an existing plant.

scholarly journals Experimental Investigation of Wave Velocity-Permeability Model for Granite Subjected to Different Temperature Processing

Geofluids ◽  
2017 ◽  
Vol 2017 ◽  
pp. 1-10 ◽  
Author(s):  
Guanghui Jiang ◽  
Jianping Zuo ◽  
Teng Ma ◽  
Xu Wei
Keyword(s):  
Particle Size ◽  
High Temperature ◽  
Wave Velocity ◽  
Pore Fluid ◽  
Rock Matrix ◽  
Permeability Model ◽  
Wave Velocities ◽  
Before And After ◽  
Different Temperatures ◽  
Increasing Temperature

Understanding the change of permeability of rocks before and after heating is of great significance for exploitation of hydrocarbon resources and disposal of nuclear waste. The rock permeability under high temperature cannot be measured with most of the existing methods. In this paper, quality, wave velocity, and permeability of granite specimen from Maluanshan tunnel are measured after high temperature processing. Quality and wave velocity of granite decrease and permeability of granite increases with increasing temperature. Using porosity as the medium, a new wave velocity-permeability model is established with modified wave velocity-porosity formula and Kozeny-Carman formula. Under some given wave velocities and corresponding permeabilities through experiment, the permeabilities at different temperatures and wave velocities can be obtained. By comparing the experimental and the theoretical results, the proposed formulas are verified. In addition, a sensitivity analysis is performed to examine the effect of particle size, wave velocities in rock matrix, and pore fluid on permeability: permeability increases with increasing particle size, wave velocities in rock matrix, and pore fluid; the higher the rock wave velocity, the lower the effect of wave velocities in rock matrix and pore fluid on permeability.

Intermetallic Effects on the Ductility of Sintered Aluminium

2008 ◽  
Vol 587-588 ◽  
pp. 380-384
Author(s):  
Jesus Cintas ◽  
José A. Rodríguez ◽  
Francicso Gomez Cuevas ◽  
José M. Gallardo
Keyword(s):  
Heat Treatment ◽  
Particle Size ◽  
Intermetallic Particle ◽  
Quantitative Metallography ◽  
Mechanically Alloyed ◽  
Aluminium Powder ◽  
Attrition Milling ◽  
Different Temperatures ◽  
Alloyed Aluminium ◽  
Milled Powders

Mechanically alloyed aluminium powder was prepared by attrition-milling for 10 hours in the presence of a wax. Milled powders were annealed in vacuum at different temperatures (500, 575, 600, 625 and 650°C). Compacts were consolidated starting from unannealed and from 600°Cannealed powders. Studies by SEM microfractography and quantitative metallography, to investigate the influence of Fe-Al intermetallics on compacts fracture, have been carried out. It is concluded that fracture takes place at regions where the area occupied by the intermetallics is high and intermetallics particles are big. Intermetallic particle size can be controlled by an appropriated heat treatment.

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...

Optimization Method of the Multistage Axial Compressors Using CFD Simulation

2021 ◽  
pp. 2141006
Author(s):  
Grigorii Popov ◽  
Igor Egorov ◽  
Evgenii Goriachkin ◽  
Oleg Baturin ◽  
Daria Kolmakova ◽  
...  
Keyword(s):  
Cfd Simulation ◽  
Optimization Problems ◽  
Search Algorithm ◽  
Pressure Ratio ◽  
Optimization Method ◽  
Cfd Modeling ◽  
Turbine Engines ◽  
Stability Margins ◽  
Axial Compressors ◽  
Cfd Models

The current level of numerical methods of gas dynamics makes it possible to optimize compressors using 3D CFD models. However, the methods and means are not sufficiently developed for their wide application. This paper describes a new method for the optimization of multistage axial compressors based on 3D CFD modeling and summarizes the experience of its application. The developed method is a complex system of interconnected components (an effective mathematical model, a parameterizer, and an optimum search algorithm). The use of the method makes it possible to improve or provide the necessary values of the main gas-dynamic parameters of the compressor by changing the shape of the blades and their relative position. The method was tested in solving optimization problems for multistage axial compressors of gas turbine engines (the number of stages from 3 to 15). As a result, an increase in efficiency, pressure ratio, and stability margins was achieved. The presented work is a summary of a long-years investigation of the research team and aims at creating a complete picture of the obtained results for the reader. A brief description of the results of industrial compresses optimization contained in the paper is given as an illustration of the effectiveness of the developed methods.

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