Process Simulation of Anchor Stirring in Crystallizer

2013 ◽  
Vol 834-836 ◽  
pp. 1548-1552
Author(s):  
Qing Wu ◽  
Li Ping Guo ◽  
Jian Xin Chen ◽  
Yin Hui Li ◽  
Ai Dang Lu
Keyword(s):  
Flow Field ◽  
Process Simulation ◽  
Chloride Solution ◽  
Single Phase ◽  
Three Dimensional ◽  
Axial Direction ◽  
Single Phase Flow ◽  
Surrounding Area ◽  
Simulation Research ◽  
Stable Flow

The paper studies the mixing effects of anchor stirring on crystallization hybrid process. The single phase flow field of three dimensional in crystallizer of 5 L is simulated by the software of Star CCM+. The change of flow field is analyzed under different stirring speed in ammonium chloride solution. The simulation research shows that the speed of fluid in the area around impeller is high, but in the surrounding and bottom area of stirring shaft is low after forming a relatively stable flow field in the crystallizer. As the stirring speed enhancement, the speed of fluid in the surrounding area of impeller and velocity gradient increase too. However, the flow of fluid in the area of axial direction is not sufficient.

Analysis of Single- and Two-Phase Flows in Turbopump Inducers

1967 ◽  
Vol 89 (4) ◽  
pp. 577-586 ◽  
Author(s):  
P. Cooper
Keyword(s):  
Equation Of State ◽  
Flow Field ◽  
Thermal Effects ◽  
Single Phase ◽  
Fluid Pressure ◽  
Three Dimensional ◽  
Pressure Rise ◽  
Recent Theory ◽  
Two Phase ◽  
Overall Efficiency

A model is developed for analytically determining pump inducer performance in both the single-phase and cavitating flow regimes. An equation of state for vaporizing flow is used in an approximate, three-dimensional analysis of the flow field. The method accounts for losses and yields internal distributions of fluid pressure, velocity, and density together with the resulting overall efficiency and pressure rise. The results of calculated performance of two sample inducers are presented. Comparison with recent theory for fluid thermal effects on suction head requirements is made with the aid of a resulting dimensionless vaporization parameter.

Influences of Axial Gap Between Blade Rows on Secondary Flows and Aerodynamic Performance in a Turbine Stage

2009 ◽  
Author(s):  
K. Yamada ◽  
K. Funazaki ◽  
M. Kikuchi ◽  
H. Sato
Keyword(s):  
Flow Field ◽  
Three Dimensional ◽  
Axial Flow ◽  
Axial Direction ◽  
Secondary Flows ◽  
Navier Stokes ◽  
Turbine Stage ◽  
Stator Vane ◽  
Is Design ◽  
Probe Measurements

A study on the effects of the axial gap between stator and rotor upon the stage performance and flow field of a single axial flow turbine stage is presented in this paper. Three axial gaps were tested, which were achieved by moving the stator vane in the axial direction while keeping the disk cavity constant. The effect of the axial gap was investigated at two different conditions, that is design and off-design conditions. The unsteady three-dimensional flow field was analyzed by time-accurate RANS (Reynolds-Averaged Navier-Stokes) simulations. The simulation results were compared with the experiments, in which total pressure and the time-averaged flow field upstream and downstream of the rotor were obtained by five-hole probe measurements. The effect of the axial gap was confirmed in the endwall regions, and obtained relatively at off-design condition. The turbine stage efficiency was improved almost linearly by reducing the axial gap at the off-design condition.

Simulation Research on Micro-Cavity Flow Field Characteristics of Liquid Floating Rotor Gyro

2013 ◽  
Vol 562-565 ◽  
pp. 490-495 ◽  
Author(s):  
Yu Peng Shi ◽  
Fei Tang ◽  
Xiao Hao Wang
Keyword(s):  
Flow Field ◽  
Boundary Conditions ◽  
Three Dimensional ◽  
Flow Characteristics ◽  
Cavity Flow ◽  
Three Dimensional Model ◽  
Simulation Research ◽  
Resistance Torque ◽  
Flow Field Characteristics ◽  
Micro Cavity

The liquid floating rotor gyro is a gyroscope using electrostatic or electromagnetic forces to levitate rotor, and filling rotor-stator cavities with liquid in order to improve stability of motion. Under influence of the relative surface roughness, rotor velocity, dimension of flow field and fluid nature, flow characteristics of cavity flow field vary under different boundary conditions and geometrical conditions. This paper adopts three-dimensional model and periodic boundary conditions to conduct numerical modeling on cavity flow field. Its results show that, with velocity rising, distribution of flow field speed and pressure manifests partial fluctuations in turbulent-flow-intensive area; resistance torque amid rotor rotation is nonlinearly correlated with velocity, whose rules can be obtained through high-order curve fitting.

Single Phase Flow in the Randomly Packed Bed With Spheres: Simulation and Experimental Validation

2016 ◽  
Author(s):  
Nan Zhang ◽  
Zhongning Sun ◽  
Ming Ding
Keyword(s):  
Single Phase ◽  
Complex Geometry ◽  
Three Dimensional ◽  
Particle Diameter ◽  
Flow Characteristics ◽  
Packed Bed ◽  
Spherical Particles ◽  
Phase Flow ◽  
Single Phase Flow ◽  
Local Flow

A computational fluid dynamic (CFD) model for single phase flow in the three dimensional randomly packed bed with spherical particles has been developed and validated with experimental results. The flow characteristics within this complex geometry are very complicated. In order to obtain insight into the interior and local flow characteristics, Three-dimensional simulation is required. First, we constructed the randomly packed bed with spherical particle, using Discrete Element Method (DEM) based on the integration of Newton’s laws of motion. To validate the DEM simulations the global bed porosity and the radial porosity distribution were compared with empirical correlation from literature. Second, the complex geometrical properties of random packed bed make it difficult to produce a fine mesh. Herein, the bridge method for meshing the particle-particle and particle-wall contact points in the packed bed was applied. The contact zones are modified and then partitioned into several regular parts, so the structure gird was meshed. Finally, the simulation of water flow in the randomly packed bed with a tube-to-particle diameter ratio of 6.325 has been carried out by the commercial CFD code. A comparison with previously published correlations and experimental data shows that the relationship proposed by KTA agree well with the measured pressure drop. Furthermore the results of simulation for distribution of velocity in the bed were analyzed and discussed.

Experimental and Numerical Investigation of Gravity-Driven Pipe Flow With Cavitation

2002 ◽  
Author(s):  
Tobias Giese ◽  
Eckart Laurien ◽  
Wolfgang Schwarz
Keyword(s):  
Mass Flux ◽  
Pipe Flow ◽  
Single Phase ◽  
Two Phase Flow ◽  
Three Dimensional ◽  
Phase Flow ◽  
Single Phase Flow ◽  
Two Phase ◽  
One Dimensional ◽  
Gravity Driven

Gravity driven pipe flows contain no risk of pump failure and are considered to be reliable even under accident conditions. However, accurate prediction methods are only available for single phase flow. In case of the occurrence of two-phase flow (caused e.g. by boiling or cavitation), a considerable reduction in mass flux can be observed. In this study, an experimental and numerical investigation of gravity driven two-phase pipe flow was performed in order to understand and model such flows. An experiment was conducted to analyse gravity driven flow of water near saturation temperature in a complex pipe consisting of several vertical and horizontal sections. The diameter was 100 mm with a driving height of 13 m between an elevated tank and the pipe outlet. The experiment shows that cavitation leads to formation of steam. The two-phase character of the flow causes a significant reduction of mass flux in comparison to a single phase flow case. The experimental flow rate was reproduced by one dimensional single and two phase flow analysis based on standard one dimensional methods including models for steam formation. The main part of this study consists of a three dimensional CFD analysis of the two phase flow. A three dimensional model for cavitation and recondensation phenomena based on thermal transport processes was developed, implemented and validated against our experimental data. Due to the fact that beside bubbly flow, also the stratified and droplet flow regimes occur, a new approach to model phase interaction terms of the Two-Fluid Model for mass, momentum and energy is presented. Thereby, the transition from one flow regime to another is taken into account. The experimental mass flow rate can be predicted with an accuracy of 10%. The three dimensional analysis of the flow situation demonstrates the influence of pipe elements such as horizontal and vertical sections, bends and valves of the pipe on the mass flux and the steam distribution. The analysis of secondary flows in bends emphases their importance for the steam distribution within the pipe, for the pressure loss and the average mass flux.

Numerical Analysis of the Flow Field in the Nozzle of Hot Water Rocket Motor

2014 ◽  
Vol 1016 ◽  
pp. 635-639 ◽  
Author(s):  
Wei Wei Sun ◽  
Zhi Jun Wei
Keyword(s):  
Numerical Simulation ◽  
Numerical Analysis ◽  
Flow Field ◽  
Single Phase ◽  
Rocket Motor ◽  
Hot Water ◽  
Phase Flow ◽  
Single Phase Flow ◽  
Working Process ◽  
Flow Process

Flashing is an important factor in the working process of hot water rocket motor. In order to deeply understand the performance characteristic of hot water rocket motor, a numerical simulation model of the flow field in the nozzle was established in this paper. According to the study of flow field in the nozzle of the motor,it is found that the phase change occurs at the position of the throat,and the flow reaches to supersonic after the throat because of the changing sound speed.The flow in the nozzle can be divided into three processes in this paper: single-phase flow process, flash process and expand-accelerating process.

BACCHUS-3D/SP, A Computer Program to Describe Transient Three-Dimensional Single Phase Flow in LMFBR Rod Bundles

1985 ◽  
Vol 71 (1) ◽  
pp. 43-67 ◽  
Author(s):  
Maurizio Bottoni ◽  
Burkhardt Dorr ◽  
Christoph Homann ◽  
Dankward Struwe
Keyword(s):  
Computer Program ◽  
Single Phase ◽  
Three Dimensional ◽  
Phase Flow ◽  
Single Phase Flow ◽  
Rod Bundles

Fine-Scale Simulation of Sandstone Acidizing

2005 ◽  
Vol 127 (3) ◽  
pp. 225-232 ◽  
Author(s):  
Chunlou Li ◽  
Tao Xie ◽  
Maysam Pournik ◽  
Ding Zhu ◽  
A. D. Hill
Keyword(s):  
Flow Field ◽  
Three Dimensional ◽  
Axial Direction ◽  
Three Dimensions ◽  
Scale Model ◽  
Small Scale ◽  
Fine Scale ◽  
Homogeneous Case ◽  
The Matrix ◽  
Highly Correlated

We have developed a fine-scale model of the sandstone core acid flooding process by solving acid and mineral balance equations for a fully three-dimensional flow field that changed as acidizing proceeded. The initial porosity and mineralogy field could be generated in a correlated manner in three dimensions; thus, a laminated sandstone could be simulated. The model has been used to simulate sandstone acidizing coreflood conditions, with a 1in.diam by 2in. long core represented by 8000 grid blocks, each having different initial properties. Results from this model show that the presence of small-scale heterogeneities in a sandstone has a dramatic impact on the acidizing process. Flow field heterogeneities cause acid to penetrate much farther into the formation than would occur if the rock were homogeneous, as is assumed by standard models. When the porosity was randomly distributed (sampled from a normal distribution), the acid penetrated up to twice as fast as in the homogeneous case. When the porosity field is highly correlated in the axial direction, which represents a laminated structure, acid penetrates very rapidly into the matrix along the high-permeability streaks, reaching the end of the simulated core as much as 17 times faster than for a homogeneous case.

scholarly journals Verification benchmarks for single-phase flow in three-dimensional fractured porous media

2021 ◽  
Vol 147 ◽  
pp. 103759 ◽  
Author(s):  
Inga Berre ◽  
Wietse M. Boon ◽  
Bernd Flemisch ◽  
Alessio Fumagalli ◽  
Dennis Gläser ◽  
...  
Keyword(s):  
Porous Media ◽  
Single Phase ◽  
Three Dimensional ◽  
Fractured Porous Media ◽  
Phase Flow ◽  
Single Phase Flow

scholarly journals Numerical Simulation of a Single-Phase Flow Through Fractures with Permeable, Porous and Non-Ductile Walls

2017 ◽  
Vol 7 (5) ◽  
pp. 2041-2046
Author(s):  
N. Pour Mahmoud ◽  
A. Zabihi
Keyword(s):  
Fluid Dynamics ◽  
Numerical Simulation ◽  
Single Phase ◽  
Phase Flow ◽  
Single Phase Flow ◽  
Surrounding Area ◽  
Fracture Geometry ◽  
Pressure Drops ◽  
Permeable Walls ◽  
Flow Through

This paper attempts to study flows within fractures through a set of numerical simulations. In addition, a special care is given to hydraulic features and characteristics of fractures. The research is performed through the application of calculative fluid dynamics and a finite volume discrete schema. The investigated flows are laminar, single-phase and stable flows of water and air through fractures with penetrable walls. The selected fracture geometry is inspired from the tomographic scan of a stone fracture. Water and air are modeled in fractures with permeable walls and different permeability levels. It has been observed that in case of permeable matrixes, the friction coefficient is lower compared to impermeable matrixes. In fact permeability reduced friction. In addition, highest pressure drops were observed in areas with smaller fracture diaphragms. Nonetheless, the surrounding area of the fracture is analyzed with the consideration of Darcy's rule.

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