scholarly journals Two-phase CFD simulation of the monodyspersed suspension hydraulic behaviour in the tank apparatus from a circulatory pipe

2008 ◽  
Vol 10 (1) ◽  
pp. 22-27 ◽  
Author(s):  
Roch Plewik ◽  
Piotr Synowiec ◽  
Janusz Wójcik
Keyword(s):  
Cfd Simulation ◽  
Fluidised Bed ◽  
Cfd Simulations ◽  
Two Phase ◽  
Hydraulic Behaviour ◽  
Hydraulic Conditions ◽  
The One ◽  
Cfd Method ◽  
Multi Phase ◽  
The Ideal

Two-phase CFD simulation of the monodyspersed suspension hydraulic behaviour in the tank apparatus from a circulatory pipe The hydrodynamics in fluidized-bed crystallizers is studied by CFD method. The simulations were performed by a commercial packet of computational fluid dynamics Fluent 6.x. For the one-phase modelling (15), a standard k-ε model was applied. In the case of the two-phase flows the Eulerian multi-phase model with a standard k-ε method, aided by the k-ε dispersed model for viscosity, has been used respectively. The collected data put a new light on the suspension flow behaviour in the annular zone of the fluidised bed crystallizer. From the presented here CFD simulations, it clearly issues that the real hydraulic conditions in the fluidised bed crystallizers are far from the ideal ones.

PARTITION FUNCTION OF THE GAS-LIQUID COEXISTENT SYSTEM

2007 ◽  
Vol 21 (21) ◽  
pp. 3755-3764
Author(s):  
SUHONG ZHANG ◽  
ZIJING LI ◽  
YUANXING GUI ◽  
WEI WANG
Keyword(s):  
Partition Function ◽  
Thermodynamic Limit ◽  
Particle System ◽  
Phase Region ◽  
Horizontal Line ◽  
Fluid System ◽  
Two Phase ◽  
The One ◽  
Multi Phase ◽  
Finite Particle

In this article the equilibrious gas-liquid coexistent system is studied, and a new expression of partition function (PF) corresponding to the two-phase region is derived. Based on this expression, the horizontal line in the isotherm of pressure versus volume is obtained naturally for a finite particle system (i.e., without the necessity of taking the thermodynamic limit). Extending this PF, we can gain a unitive form of the one-component fluid in any system (i.e., one-phase or multi-phase). Then the whole isotherm will have reasonable statistical foundation. The VDW fluid system is discussed as a concrete example.

Two-Phase Flow CFD Simulations of Bubble Crystallization Tube

2012 ◽  
Vol 557-559 ◽  
pp. 2383-2387
Author(s):  
Peng Fei Zhang ◽  
Jian Long Hou ◽  
Ke Xue Fang
Keyword(s):  
Two Phase Flow ◽  
Operating Parameters ◽  
Phase Flow ◽  
Gas Velocity ◽  
Cfd Simulations ◽  
Two Phase ◽  
Inlet Velocity ◽  
Computing Platform ◽  
Multi Phase ◽  
Form Condition

At present, the studies of bubble crystallization focus on the gas velocity, crystallization efficiency and crystallization yield, the effects of other factors were not considered. So it is very important to study factors comprehensively that effect on the gas-liquid two-phase flow of bubble crystallization. In this paper, Fluent was used as a computing platform and RNG k-ε turbulence model and VOF multi-phase model was selected to simulate gas-liquid two-phase flow of bubble crystallization. The results show that as the gas inlet velocity increases, slug bubbles are more and more bigger, more and more dispersed bubbles are below the slug bubbles, crystallization efficiency first increases and then decreases; Under the gas pulse-inlet form condition, the better operating parameters are: gas velocity 1.0m/s, pulse duration 0.4s, interval time 0.8s, crystallization tube diameter 40mm. Simulations agree well with experimental data.

Influence of Jordanian zeolite on the performance of a solar still: experiments and CFD simulation studies

2016 ◽  
Vol 16 (6) ◽  
pp. 1700-1709 ◽  
Author(s):  
Yazan Taamneh
Keyword(s):  
Experimental Data ◽  
Phase Change ◽  
Cfd Simulation ◽  
Volume Fraction ◽  
Solar Still ◽  
Cfd Simulations ◽  
Two Phase ◽  
Vof Model ◽  
Computational Fluid Dynamics Cfd ◽  
Good Agreement

Computational fluid dynamics (CFD) simulations were performed for experiments carried out with two identical pyramid-shaped solar stills. One was filled with Jordanian zeolite-seawater and the second was filled with seawater only. This work is focused on CFD analysis validation with experimental data conducted using a model of phase change interaction (evaporation-condensation model) inside the solar still. A volume-of-fluid (VOF) model was used to simulate the inter phase change through evaporation-condensation between zeolite-water and water vapor inside the two solar stills. The effect of the volume fraction of the zeolite particles (0 ≤ ϕ ≤ 0.05) on the heat and distillate yield inside the solar still was investigated. Based on the CFD simulation results, the hourly quantity of freshwater showed a good agreement with the corresponding experimental data. The present study has established the utility of using the VOF two phase flow model to provide a reasonable solution to the complicated inter phase mass transfer in a solar still.

Development of a Simplified Methodology for Evaluation of Piping Vibration due to Multi-Phase Flow

2015 ◽  
Author(s):  
Humberto R. Santos ◽  
Michèle S. Pfeil ◽  
Ediberto B. Tinoco ◽  
Ronaldo C. Battista
Keyword(s):  
Boundary Conditions ◽  
Multiphase Flow ◽  
Feasible Solution ◽  
Piping System ◽  
Phase Flow ◽  
Two Phase ◽  
Multi Phase Flow ◽  
The One ◽  
Multi Phase ◽  
Acceleration Signals

Excessive piping vibration is a major cause of idleness, leaks, failures, fires and explosions in the petrochemical industry. One of the causes of vibration in piping is the occurrence of multiphase flow regimes, specially the one called slug flow. The main purpose of this work is the verification and improvement of a methodology for evaluation of excessive piping vibration caused by multiphase flow. This methodology is capable of generating, from the measured acceleration signals, forces equivalent to those induced by the two-phase flow. In other words, this methodology enables simplified models to represent adequately the dynamic structural behavior of the piping system when new boundary conditions are imposed, allowing to estimate the risk of failure in operation of piping system or to propose technically feasible solution to mitigate the vibration problem. A physical model made of acrylic pipes and PVC bends was assembled and used to measure, simultaneously, the accelerations at four points of this loop when subjected to multiphase flow and with two different boundary conditions. The methodology could therefore be applied, refined, and validated with the data obtained from the experiment and with the aid of numerical simulation.

CFD Simulation Study of Gas-Liquid Flow Regimes in Inclined Wellbore

2014 ◽  
Vol 915-916 ◽  
pp. 126-130
Author(s):  
Yin Di Zhang ◽  
Long Fei Ruan ◽  
De Hua Liu
Keyword(s):  
Inclination Angle ◽  
Cfd Simulation ◽  
Fluid Dynamic ◽  
Flow Regimes ◽  
Two Phase ◽  
Flow Rates ◽  
Flow Regime Transition ◽  
Gas Liquid Flow ◽  
Cfd Method ◽  
Good Agreement

Computational Fluid Dynamic (CFD) was used to investigate gas-liquid two phase flow regimes for the inclined wells. The simulation results were compared with the Taitel chart. A good agreement between the prediction and the Taitel flow regimes shows that CFD method can reasonably predict flow regimes in the inclined well. Another further study was conducted to explore the influence of flow rates and inclination angle on flow regimes. The results show both of flow rates and inclination angle have a significant effect on flow regime transition.

scholarly journals Approach to 3D Unsteady CFD Analysis of a Single-Blade Pump

2020 ◽  
Vol 328 ◽  
pp. 02016
Author(s):  
Kurilla Matej ◽  
Knížat Branislav ◽  
Olšiak Róbert
Keyword(s):  
Cfd Simulation ◽  
Centrifugal Pumps ◽  
Cfd Simulations ◽  
Ansys Fluent ◽  
Ansys Cfx ◽  
Hydraulic Machines ◽  
Element Number ◽  
The One ◽  
User Friendly ◽  
Blade Pump

Single-blade centrifugal pumps are hydraulic machines used in many industrial areas. A unique screw shaped blade enables liquids containing solids and fibrous matters to be pumped. Owing to good pump hydraulic properties on the one hand and unfavourable impeller mechanical properties on the other have single-blade pumps become recently more interesting for researchers regarding the CFD simulations. In this case a conventional CFD approach for multi-blade pumps cannot be applied due to the lack of symmetry of the single-blade impeller. Possible approaches to the CFD simulation of a single-blade impeller in the Ansys Fluent and the Ansys CFX are compared in this paper. A comparison of two CFD meshing tools showed substantial element number decrease of the whole CFD model. This paper presents also the laboratory experiment results of the investigated single-blade pump. The paper describes a new approach to the single-blade CFD simulation through Ansys Fluent which is faster and more user-friendly then the conventional approach.

scholarly journals Validation of CFD Simulations of Cerebral Aneurysms With Implication of Geometric Variations

2006 ◽  
Vol 128 (6) ◽  
pp. 844-851 ◽  
Author(s):  
Yiemeng Hoi ◽  
Scott H. Woodward ◽  
Minsuok Kim ◽  
Dale B. Taulbee ◽  
Hui Meng
Keyword(s):  
Flow Field ◽  
Cfd Simulation ◽  
Three Dimensional ◽  
Cerebral Aneurysms ◽  
Patient Specific ◽  
Hemodynamic Parameters ◽  
Cfd Simulations ◽  
Piv Measurements ◽  
Cfd Method ◽  
Aneurysm Model

Background. Computational fluid dynamics (CFD) simulations using medical-image-based anatomical vascular geometry are now gaining clinical relevance. This study aimed at validating the CFD methodology for studying cerebral aneurysms by using particle image velocimetry (PIV) measurements, with a focus on the effects of small geometric variations in aneurysm models on the flow dynamics obtained with CFD. Method of Approach. An experimental phantom was fabricated out of silicone elastomer to best mimic a spherical aneurysm model. PIV measurements were obtained from the phantom and compared with the CFD results from an ideal spherical aneurysm model (S1). These measurements were also compared with CFD results, based on the geometry reconstructed from three-dimensional images of the experimental phantom. We further performed CFD analysis on two geometric variations, S2 and S3, of the phantom to investigate the effects of small geometric variations on the aneurysmal flow field. Results. We found poor agreement between the CFD results from the ideal spherical aneurysm model and the PIV measurements from the phantom, including inconsistent secondary flow patterns. The CFD results based on the actual phantom geometry, however, matched well with the PIV measurements. CFD of models S2 and S3 produced qualitatively similar flow fields to that of the phantom but quantitatively significant changes in key hemodynamic parameters such as vorticity, positive circulation, and wall shear stress. Conclusion. CFD simulation results can closely match experimental measurements as long as both are performed on the same model geometry. Small geometric variations on the aneurysm model can significantly alter the flow-field and key hemodynamic parameters. Since medical images are subjected to geometric uncertainties, image-based patient-specific CFD results must be carefully scrutinized before providing clinical feedback.

CFD Simulation of the Gas-Liquid Flow on the Ripple Tray

2012 ◽  
Vol 472-475 ◽  
pp. 1605-1609
Author(s):  
Bin Jiang ◽  
Zhong Tao Li ◽  
Lu Hong Zhang
Keyword(s):  
Cross Sections ◽  
Cfd Simulation ◽  
Euler Method ◽  
Two Phase ◽  
Sieve Tray ◽  
Computational Fluid Dynamics Cfd ◽  
Gas Liquid Flow ◽  
Experimental Values ◽  
Cfd Method ◽  
Superficial Gas Velocity

The ripple tray is a sieve tray without downcomers, in which the liquid contacts with the upward gas counter-currently. The hydrodynamics performance in ripple tray columns was investigated with the computational fluid dynamics (CFD) method. Various superficial gas velocity and liquid loads were simulated for the tray with cylindrical cross sections using the Euler-Euler method. The modeling results were validated by comparing the calculated liquid height on the ripple tray with the experimental values. The developed CFD model is found to be able to predict the two phase flow patterns in ripple tray columns and provide useful information for further design of ripple tray.

Numerical Simulation and Structure Optimization of Converter Gas Evaporative Cooler

2013 ◽  
Author(s):  
Zeyi Jiang ◽  
Pengyuan Chen ◽  
Pan Liu ◽  
Guanghe Tian
Keyword(s):  
Numerical Simulation ◽  
Mass Transfer ◽  
Cfd Simulation ◽  
Engineering Application ◽  
Discrete Phase Model ◽  
Engineering Project ◽  
Two Phase ◽  
Flow Process ◽  
Evaporative Cooler ◽  
Cfd Method

In Lurgi-Thyssen dedusting system of steelmaking converter, the evaporative cooler represents a crucial operating unit, in which the hot dust-laden flue gas has to be cooled by saturation with water. The cooling process of the gas consists of gas-liquid two phase flow and interphase heat and mass transfer. In this paper, k-epsilon standard equations and Lagrange discrete phase model are employed to describe the gas turbulent flow and the heat/mass transfer with droplet evaporation individually. The computational fluid dynamics (CFD) simulation for practical engineering project shows that the large-flux cooling gas is commonly constructed in a non-uniform flow caused by the sharp turnings at the inlet and outlet channels. The unevenness of velocity distribution and the effective cooling height are defined in this paper to evaluate the cooling flow process. A series of newly designed structures with guide plate are investigated by CFD method to eliminate the problems with the non-uniformity. The results of numerical simulation show that optimal designed guide ring plate could improve the flow uniformity and the heat transfer. The investigations have been used to guide the engineering application.

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