Investigation on Influence of Launch Depth to the Hydrodynamic Characteristics of the Cylinder out of the Tube

2011 ◽  
Vol 328-330 ◽  
pp. 2261-2264
Author(s):  
Hai Jun Liu ◽  
Xing Zhi Peng ◽  
Cong Wang ◽  
Ben Li Wang
Keyword(s):  
Numerical Simulation ◽  
Flow Field ◽  
Resistance Coefficient ◽  
Viscous Drag ◽  
Hydrodynamic Characteristics ◽  
Multiphase Model ◽  
Pressure Drag ◽  
Simulation Results ◽  
Volume Method ◽  
Mesh Technique

The influence of different the depth to the hydrodynamic characteristics of the underwater cylinder vertical launch out of the tube was researched with numerical simulation. The finite volume method based on the multiphase model, continuity equation, transport equations of liquid mass fraction,a dynamic mesh technique and a standard tow-turbulence model are adopted to solve RANS equation in conjunction. The fluid-solid coupling problem of both movement boundary of the cylinder and multiphase flow field was solved by using numerical method. Under the influence of the gravity, the flow field affected the hydrodynamic characteristics of the cylinder was derived with the numerical simulation. Simulation results show that different launch depths affect on the trajectory of underwater cylinder and hydrodynamic. The fluctuation reasons of different pressure drag coefficient, viscous drag resistance coefficient and toll resistance coefficient were derived by analyzing simulation results.

Numerical Simulation of Powder Dispersion Performance by Different Mesh Types

2016 ◽  
Vol 680 ◽  
pp. 82-85
Author(s):  
Jian Cai ◽  
Lan Chen ◽  
Umezuruike Linus Opara
Keyword(s):  
Numerical Simulation ◽  
Flow Field ◽  
Fine Particle ◽  
Particle Deposition ◽  
Tetrahedral Mesh ◽  
Computational Time ◽  
Kinetic Characteristics ◽  
Powder Dispersion ◽  
Simulation Results ◽  
Time Accuracy

OBJECTIVE To investigate the influence of mesh type on numerical simulating the dispersion performance of micro-powders through a home-made tube. METHODS With the computational fluid dynamics (CFD) method, a powder dispersion tube was meshed in three different types, namely, tetrahedral, unstructured hexahedral and prismatic-tetrahedral hybrid meshes. The inner flow field and the kinetic characteristics of the particles were investigated. Results of the numerical simulation were compared with literature evidences. RESULTS The results showed that using tetrahedral mesh had the highest computational efficiency, while employing the unstructured hexahedral mesh obtained more accurate outlet velocity. The simulation results of the inner flow field and the kinetic characteristics of the particles were slightly different among the three mesh types. The calculated particle velocity using the tetrahedral mesh had the best correlation with the changing trend of the fine particle mass in the first 4 stages of the new generation impactor (NGI) (R2 = 0.91 and 0.89 for powder A and B, respectively). Conclusions Mesh type affected computational time, accuracy of simulation results and the prediction abilities of fine particle deposition.

scholarly journals Slit Wall Effect on the Stability of Wavy Vortex Flow

2014 ◽  
Vol 6 ◽  
pp. 853069 ◽  
Author(s):  
Dong Liu ◽  
Ying-ze Wang ◽  
Hyoung-Bum Kim ◽  
Fang-neng Zhu ◽  
Chun-lin Wang
Keyword(s):  
Numerical Simulation ◽  
Flow Field ◽  
Radial Velocity ◽  
Flow Regime ◽  
Experimental Measurement ◽  
Vortex Flow ◽  
Wall Effect ◽  
Taylor Vortices ◽  
Simulation Results ◽  
The Stability

The wavy vortex flow in the plain model was studied by experimental measurement; the preliminary feature of wavy vortex flow was obtained. This flow field in the plain model was also studied by numerical simulation. The reliability of numerical simulation was verified by comparing with the experimental and numerical simulation results. To study the slit wall effect on the wavy vortex flow regime, another two models with different slit number were considered; the slit number was 6 and 12. By comparing the wavy vortex flow field in different models, the axial fluctuation of Taylor vortices was found to be different, which was increased with the increasing of slit number. The maximum radial velocity from the inner cylinder to the outer one in the 6-slit number was increased by 12.7% compared to that of plain model. From the results of different circumferential position in the same slit model, it can be found that the maximum radial velocity in slit plane is significantly greater than that in other planes. The size of Taylor vortices in different models was also calculated, which was found to be increased in the 6-slit model but was not changed as the slit number increased further.

Study on flow field of gas–solid two-phase pulsed jet

2019 ◽  
Vol 33 (24) ◽  
pp. 1950279
Author(s):  
Xinhua Song ◽  
Xiaojie Li ◽  
Yang Wang ◽  
Honghao Yan
Keyword(s):  
Numerical Simulation ◽  
Flow Field ◽  
Particle Distribution ◽  
Starch Granule ◽  
Injection Pressure ◽  
Two Phase ◽  
Particle Injection ◽  
Pulsed Jet ◽  
Simulation Based ◽  
Simulation Results

In this paper, a computational fluid dynamics–discrete element method (CFD–DEM) coupling method is established to simulate the starch granule injection by coupling CFD and DEM. Then a gas–solid two-phase pulsed jet system is designed to capture the flow field trajectory of particle injection (colored starch with a mean diameter of 10.67 [Formula: see text]m), and the image is processed by color moment and histogram. Finally, the simulation results are compared with the experimental results, and the following conclusions are drawn. The numerical simulation results show that with the increase of injection pressure, the injection height increases gradually. When the injection pressure reaches above 0.4 MPa, the increase of injection height decreases. The experimental images show that the larger the pressure (i.e., the greater the initial velocity), the faster the velocity of particle distribution in the space, and the injection heights with the injection pressures of 0.4 MPa and 0.5 MPa are close, which is consistent with the result from the FLUENT numerical simulation based on CFD–DEM.

Study on the Principle of Yarn Splicing of Pneumatic Splicer Using Numerical Simulation

2012 ◽  
Vol 588-589 ◽  
pp. 1355-1358
Author(s):  
Xiao Xing ◽  
Guo Ming Ye
Keyword(s):  
Numerical Simulation ◽  
Flow Field ◽  
Three Dimensional ◽  
Numerical Results ◽  
Simulation Results

During the splicing process of pneumatic splicer, the principle of yarn splicing is closely related to the flow field inside the splicing chamber. This paper presents a numerical simulation of the flow char-acteristics inside the splicing chamber of the pneumatic splicer. A three-dimensional grid and the realizable tur¬bulence model are used in this simulation. The numerical results of veloc¬ity vectors distribution inside the chamber are shown. Streamlines starting from the two air injectors are also acquired. Based on the simulation, the principle of yarn splicing of the pneumatic splicer is discussed. The airflow in the splicing chamber can be divided into three regions. In addition, the simulation results have well sup¬ported the principle of yarn splicing of pneumatic splicer claimed by the splicing chamber makers.

Numerical Simulation of the Flow Field in Cavitations Nozzle for Impinging Streams Reactor

2010 ◽  
Vol 139-141 ◽  
pp. 1048-1051 ◽  
Author(s):  
Qin Li ◽  
Hui Lin Wang ◽  
Fu Bao Li
Keyword(s):  
Numerical Simulation ◽  
Flow Field ◽  
Surrounding Medium ◽  
Analytical Calculation ◽  
Simple Algorithm ◽  
Shear Effect ◽  
Outlet Pressure ◽  
Pressure Distributions ◽  
Strong Shear ◽  
Simulation Results

The pressure distributions in cavitations nozzle of three different structures were studied by Hydromechanics theory, the models and mashes were completed by using Gambit software, for the conditions of the inlet pressure to 20MPa and the outlet pressure to 0.1MPa, the flow field within cavitations nozzles is simulated based on the standard k-ε model and the SIMPLE algorithm with Fluent. The result of numerical simulation is consistent with that of analytical calculation. Simulation results show that the flow has a strong shear effect with the surrounding medium in the diffuser, resulting in significant negative pressure, which is conducive to the formation of cavitations bubbles. The angle nozzle is best selected for impinging streams cavitations reactor on this basis in the paper.

Numerical Simulation of Flow Field of Inflation Pressure for Large Complex Sulfide Mineral of Low-Tin Flotation Machine

2013 ◽  
Vol 341-342 ◽  
pp. 333-336
Author(s):  
Ming Zhen Hu ◽  
Bo Zeng Wu ◽  
Jin Quan Chen ◽  
Ji Shu Zeng
Keyword(s):  
Fluid Dynamics ◽  
Numerical Simulation ◽  
Flow Field ◽  
Sulfide Mineral ◽  
Inflation Pressure ◽  
Flotation Machine ◽  
Complex Sulfide ◽  
Flow Field Characteristics ◽  
Machine Simulation ◽  
Simulation Results

For flotation characteristics of complex sulfide mineral of low-tin in Guangxi Dachang mine, fluid dynamics software FLUENT was applied to simulate the turbulence intensity of slurry fluid in flotation machine at different inflation pressures. The effect of flow field characteristics was gotten for flotation machine. Simulation results show that the best inflation pressure was 120000 Pa.

Numerical Simulation of Blade Channel Vortex in a Low Head Francis Turbine

2013 ◽  
Vol 291-294 ◽  
pp. 1958-1962 ◽  
Author(s):  
Hong Ming Zhang ◽  
Li Xiang Zhang
Keyword(s):  
Numerical Simulation ◽  
Francis Turbine ◽  
Transfer Model ◽  
Mass Transfer Model ◽  
Governing Equations ◽  
Cavitation Model ◽  
Finite Rate ◽  
Low Head ◽  
Simulation Results ◽  
Volume Method

The paper presents numerical simulation of blade channel vortex in a low head Francis turbine using OpenFoam code. A mixture assumption and a finite rate mass transfer model were introduced to analyze blade channel vortex. The finite volume method is used to solve the governing equations of the mixture model and the pressure-velocity coupling is handled via a Pressure Implicit with Splitting of Operators (PISO) procedure. Simulation results have shown that using cavitation model to analyze blade channel vortex is very effective.

Hydrodynamic Characteristics of Dislocated Floating Ring Bearing with Different Eccentricities

2011 ◽  
Vol 52-54 ◽  
pp. 152-155
Author(s):  
Yu Jie Dai
Keyword(s):  
Numerical Simulation ◽  
Boundary Element Method ◽  
Internal Friction ◽  
Boundary Element ◽  
Hydrodynamic Characteristics ◽  
Ring Radius ◽  
Simulation Results ◽  
Element Method

For obtain the effect of floating ring radius R2 and floating ring velocity v2 on internal friction in dislocated floating ring with different eccentricities, the evolution of internal friction is simulated with boundary element method (BEM). Numerical simulation results show that internal friction increases with the increase of eccentricity. Internal friction rises linearly as the addition of floating ring velocity v2 if the eccentricity e and radius R2 are fixed. When the velocity v2 is a constant and the range of R2 is 0.75<R2<0.8, the internal friction increase enormously.

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