On equation of discrete solid particles' motion in arbitrary flow field and its properties

2000 ◽  
Vol 21 (3) ◽  
pp. 297-310 ◽  
Author(s):  
Huang Shehua ◽  
Li Wei ◽  
Cheng Liangjun
Keyword(s):  
Flow Field ◽  
Solid Particles ◽  
Arbitrary Flow

scholarly journals The Dynamics of Suspended Solid Particles in a Two Stage Gas Turbine

1986 ◽  
Author(s):  
W. Tabakoff ◽  
A. Hamed
Keyword(s):  
Flow Field ◽  
Gas Turbine ◽  
Turbine Blades ◽  
Three Dimensional ◽  
Suspended Solid ◽  
Solid Particles ◽  
Two Stage ◽  
Particle Momentum ◽  
Performance Deterioration ◽  
And Performance

Gas turbine engines operating in dusty environments are exposed to erosion and performance deterioration. In order to provide the basis for calculating the erosion and performance deterioration of turbines using pulverized coal, an investigation is undertaken to determine the three dimensional particle trajectories in a two stage turbine. The solution takes into account the influence of the variation in the three dimensional flow field. The change in particle momentum due to their collision with the turbine blades and casings is modeled using empirical equations derived from experimental Laser Doppler Velocimetry (LDV) measurements. The results show the three dimensional trajectory characteristics of the solid particles relative to the turbine blades. The results also show that the particle distribution in the flow field are determined by particle-blade impacts. The results obtained from this study indicate the turbine blade locations which are subjected to more blade impacts and hence more erosion damage.

Numerical Simulation of Sand Erosion Phenomena in Square-Section 90 Degree Bend With Linear/Nonlinear RANS Turbulence Models

2007 ◽  
Author(s):  
Masaya Suzuki ◽  
Kazuaki Inaba ◽  
Makoto Yamamoto
Keyword(s):  
Flow Field ◽  
Secondary Flow ◽  
Turbulence Models ◽  
Solid Particles ◽  
Two Phase ◽  
Streamline Curvature ◽  
Sand Erosion ◽  
Rans Turbulence Models ◽  
Wall Deformation ◽  
Bend Flow

Sand erosion is a phenomenon where solid particles impinging to a wall cause serious mechanical damages to the wall surface. This phenomenon is a typical gas-particle two-phase turbulent flow and a multi-physics problem where the flow field, particle trajectory and wall deformation interact with among others. On the other hand, the sand erosion is a serious problem to install pneumatic conveying systems for handling abrasive materials. Incidentally, the bend erosion is typical target of sand erosion experiments and is useful for verification of numerical simulations. Although, the secondary flow which occurs in such a flow field including streamline curvature cannot be reproduced by the standard k-ε model. To predict this flow field, a more universal model which can estimate anisotropic Reynolds stress is required. In the present study, we simulate sand erosion of 90 degree bend with a square cross-section. We use some linear/nonlinear turbulence models to predict the secondary flow of the bend. Besides, the performance of each model to predict clear/eroded bend flow field is studied.

Experimental and Computational Investigation of an Air Core Inside a Milling Circuit Hydroclone

2017 ◽  
Author(s):  
J. R. Kadambi ◽  
C. Shingote ◽  
R. Ke ◽  
Z. Tian ◽  
J. Furlan ◽  
...  
Keyword(s):  
Flow Field ◽  
Flow System ◽  
Industrial Applications ◽  
Solid Particles ◽  
Test Fluid ◽  
Multiphase Model ◽  
Phase Flow ◽  
Computational Results ◽  
Number Range ◽  
Air Core

Hydrocyclone separators are widely used in various industrial applications in the oil and mining industries to sort, classify and separate solid particles or liquid droplets within liquid suspensions. Often, studies in the literature have investigated idealized and simplified geometries, which are also typically scaled down to very small sizes. In this study, the two phase flow system inside a transparent acyclic model with actual milling circuit cyclone hydraulics was investigated computationally and experimentally. The diameter and height of the hydrocyclone are 12.7 cm and 94 cm, respectively. In many industrial applications, a single phase flow system in a hydrocyclone is a rarity, since nearly all cyclones have an underflow which is open to atmosphere, and therefore an air core is present along the central axis. In this study, the flow field with an air core present has been investigated. The computational modelling was conducted using Star CCM+, a commercial Computational Fluid Dynamics (CFD) software package. Large Eddy Simulation (LES) and the Volume of Fluid multiphase model was used. Additionally, the computational studies also focused on the prediction of the dimensions of the air core, which were measured experimentally. The tests were conducted in the Reynolds number range of 20,000–150,000 and 9000–67,800 for the water and NaI solution respectively. The model hydrocyclone was made of optically transparent acrylic plastic with flat, smooth outer surfaces so that there were no reflections, distortions, or obstructions. Refractive index matching, to minimize refraction effects, between the test fluid and acrylic test piece was achieved using a test liquid of sodium iodide aqueous solution (63.3% NaI by weight). Images of the flow field with the air core were taken using a Canon DSLR camera. A comparison between the experimental data and the computational results were made in the r-z plane. The experimental results and the computational results will be discussed in this paper.

ANALYSIS OF CELL ACCUMULATION MECHANISM IN A ROTATIONAL CULTURE SYSTEM

2011 ◽  
Vol 11 (02) ◽  
pp. 407-421
Author(s):  
KOJI FUKAGATA ◽  
KATSUKO S. FURUKAWA ◽  
TAKASHI USHIDA
Keyword(s):  
Numerical Simulation ◽  
Angular Velocity ◽  
Flow Field ◽  
Culture System ◽  
Water Surface ◽  
Relative Velocity ◽  
Equation Of Motion ◽  
Solid Particles ◽  
Cell Accumulation ◽  
Accumulation Mechanism

The accumulation mechanism of cells in a rotational culture device is investigated from the viewpoint of fluid mechanics. For simplicity, the deformation of the water surface is neglected and the cells are treated as spherical solid particles. From the numerical simulation of flow field with typical parameters used in the previous experiments, it is confirmed that the relative velocity of fluid induced by the rotational shaking is much smaller than the speed of rotation. From the analysis of particle equation of motion, it is found that the accumulation of cells toward the central region is found to be due to the interaction between the acceleration by rotational shaking and the drag force acting on the cells. The integral time scale for cell accumulation was estimated to be about 10 min for typical cases. The accumulation speed increases quadratically with the diameter of cell and the angular velocity of rotational shaking, which qualitatively support the previous experimental observation.

Blast waves in dusty gases

1987 ◽  
Vol 414 (1846) ◽  
pp. 197-219 ◽  
Keyword(s):  
Flow Field ◽  
Wave Front ◽  
Blast Wave ◽  
Spherical Layer ◽  
Blast Waves ◽  
Solid Particles ◽  
Dust Particles ◽  
Spatial Density ◽  
Maximum Pressure ◽  
Sharp Maximum

The conservation equations for the flow field developed behind a spherical blast wave propagating into a dusty medium (gas seeded with small uniformly distributed solid particles) are formulated and solved numerically by using the random choice method. The solution was carried out for the following three cases: (1) the dust is uniformly distributed outside the exploding spherical diaphragm; (2) the dust is uniformly distributed inside the exploding spherical diaphragm; (3) the dust is uniformly distributed inside a spherical layer located outside the exploding spherical diaphragm. The solutions obtained were compared with a similar pure-gas case. It was found that the dust presence weakens the blast wave, i. e. the gas velocity, temperature and pressure immediately behind the blast-wave front were lower than those obtained in a similar pure-gas case. The presence of dust changed the flow field behind the blast wave. The typical blast-wave pressure signature (i. e. a monotonic reduction in the pressure after the jump across the blast-wave front) changed to a different shape. Now the pressure increases after the blast-wave front until it reaches a maximum value followed by a monotonic pressure reduction. The maximum pressure is attained between the blast-wave front and the contact surface. Higher values of total pressure are obtained in the dusty gas case. The initial uniform spatial distribution of the dust particles changed into a bell-shaped pattern with a pronounced peak. The development of the sharp maximum in the dust spatial-density distribution might be of interest in assessing the effects of atmospheric nuclear explosions.

Simulation on the Flow Field of Mini-Hydrocyclones for Different Inlet Sizes

2013 ◽  
Vol 864-867 ◽  
pp. 1183-1191 ◽  
Author(s):  
Chao Yan ◽  
Qiang Yang ◽  
Hua Lin Wang
Keyword(s):  
Aspect Ratio ◽  
Flow Field ◽  
Solid Particles ◽  
Design And Optimization ◽  
Fluent Software ◽  
Simulation Results ◽  
Shape And Size

This paper aims to improve the separation of fine solid particles in mini-hydrocyclones by changing the shape and size of the mini-hydrocyclone inlet. This study also examines the best mini-hydrocyclone inlet shape and size. Fluent software is used to simulate the flow field of the continuous and dispersion phases in different mini-hydrocyclone. The simulation results can guide the design and optimization of mini-hydrocyclones and determine the optimum inlet aspect ratio.

scholarly journals Simulation of Arbitrary Flow Field Using Voxel Method

2002 ◽  
Vol 2002.15 (0) ◽  
pp. 541-542
Author(s):  
Kangbin LEI ◽  
Masako IWATA ◽  
Shigeho NODA ◽  
Ryutaro HIMENO
Keyword(s):  
Flow Field ◽  
Arbitrary Flow
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