Behaviors of Spherical and Nonspherical Particles in a Square Pipe Flow

2011 ◽  
Vol 9 (5) ◽  
pp. 1179-1192 ◽  
Author(s):  
Takaji Inamuro ◽  
Hirofumi Hayashi ◽  
Masahiro Koshiyama
Keyword(s):  
Polar Angle ◽  
Immiscible Fluids ◽  
Solid Particles ◽  
Spherical Particles ◽  
Nonspherical Particles ◽  
Fluid Mixture ◽  
Spherical Droplet ◽  
Liquid Boundary ◽  
Boltzmann Method ◽  
Solid Liquid

AbstractThe lattice Boltzmann method (LBM) for multicomponent immiscible fluids is applied to the simulations of solid-fluid mixture flows including spherical or non-spherical particles in a square pipe at Reynolds numbers of about 100. A spherical solid particle is modeled by a droplet with strong interfacial tension and large viscosity, and consequently there is no need to track the moving solid-liquid boundary explicitly. Nonspherical (discoid, flat discoid, and biconcave discoid) solid particles are made by applying artificial forces to the spherical droplet. It is found that the spherical particle moves straightly along a stable position between the wall and the center of the pipe (the Segré-Silberberg effect). On the other hand, the biconcave discoid particle moves along a periodic helical path around the center of the pipe with changing its orientation, and the radius of the helical path and the polar angle of the orientation increase as the hollow of the concave becomes large.

Investigation of the Flow Behavior of Participate Filled Fluids

1996 ◽  
Vol 445 ◽  
Author(s):  
T. E. Driscoll ◽  
P. C. Li ◽  
G. L. Lehmann ◽  
E. J. Cotts
Keyword(s):  
Large Particle ◽  
Capillary Flow ◽  
Flow Behavior ◽  
Solid Particles ◽  
Spherical Particles ◽  
Liquid Density ◽  
High Concentration ◽  
Flow Process ◽  
Fluid Mixture ◽  
Underfill Flow

AbstractUnderfill encapsulants, used in direct‐chip‐attachment (DCA) packaging of electronics, consist of an epoxy resin in which a high concentration of solid particles are suspended. As a fluid mixture key features of these encapsulants are their relatively large particle sizes and large particle‐to‐liquid density ratios (ρs/ρ0 ?2.4). Experiments have been conducted to characterize the flow behavior of model mixtures of negatively buoyant, spherical particles suspended in Newtonian liquids. Capillary flow in a parallel surface channel is used to simulate the underfill flow process. The effects of varying the channel spacing, particle size and liquid carrier are reported here. The flow behavior is contrasted with a linear fluid, effective viscosity model. Particle settling appears to be linked to the more complex behavior observed in both our model suspensions and measurements using an actual commercial encapsulant.

Insight From Recent Experimental and Empirical-Model Studies on Flow-Regime Characteristics in Debris Bed Formation Behavior

2018 ◽  
Vol 4 (3) ◽  
Author(s):  
Songbai Cheng ◽  
Ting Zhang ◽  
Jinjiang Cui ◽  
Pengfeng Gong ◽  
Yujia Qian
Keyword(s):  
Flow Regime ◽  
Empirical Model ◽  
Particle Density ◽  
Model Development ◽  
Solid Particles ◽  
Spherical Particles ◽  
Experimental Investigations ◽  
Nonspherical Particles ◽  
Model Studies ◽  
Formation Behavior

Studies on debris bed formation behavior are important for improved evaluation of core relocation and debris bed coolability that might be encountered in a core disruptive accident (CDA) of sodium-cooled fast reactors (SFR). Motivated to clarify the flow-regime characteristics underlying this behavior, both experimental investigations and empirical-model development are being performed at the Sun Yat-sen University in China. As for the experimental study, several series of simulated experiments are being conducted by discharging various solid particles into water pools. To obtain a comprehensive understanding, a variety of experimental parameters, including particle size (0.000125– 0.008 m), particle density (glass, aluminum, alumina, zirconia, steel, copper, and lead), particle shape (spherical and nonspherical), and water depth (0–0.8 m) along with the particle release pipe diameter (0.01–0.04 m) were varied. It is found that due to the different interaction mechanisms between solid particles and water pool, four kinds of flow regimes, termed, respectively, as the particle-suspension regime, the pool-convection dominant regime, the transitional regime, and the particle-inertia dominant regime, were identifiable. As for the empirical-model development, aside from a base model which is restricted to predictions of spherical particles, in this paper considerations on how to cover more realistic conditions (esp. debris of nonspherical shapes) are also discussed. It is shown that by coupling the base model with an extension scheme, respectable agreement between experiments and model predictions for regime transition can be achieved for both spherical and nonspherical particles given our current range of conditions.

scholarly journals Numerical Simulation of Three-Dimensional Dendrite Movement Based on the CA–LBM Method

Crystals ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1056
Author(s):  
Qi Wang ◽  
Yingming Wang ◽  
Shijie Zhang ◽  
Binxu Guo ◽  
Chenyu Li ◽  
...  
Keyword(s):  
3D Model ◽  
Three Dimensional ◽  
Solidification Process ◽  
Movement Direction ◽  
Liquid Boundary ◽  
Alloy Microstructure ◽  
The Difference ◽  
Boltzmann Method ◽  
Solid Liquid ◽  
2D Model

At present, the calculation of three-dimensional (3D) dendrite motion using the cellular automata (CA) method is still in its infancy. In this paper, a 3D dendrite motion model is constructed. The heat, mass, and momentum transfer process in the solidification process of the alloy melt are calculated using a 3D Lattice–Boltzmann method (LBM). The growth process for the alloy microstructure is calculated using the CA method. The interactions between dendrites and the melt are assessed using the Ladd method. The solid–liquid boundary of the solute field in the movement process is assessed using the solute extrapolation method. The translational velocity of the equiaxed crystals in motion is calculated using the classical mechanical law. The rationality of the model is verified and the movement of single and multiple 3D equiaxed crystals is simulated. Additionally, the difference between 3D dendrite movement and two-dimensional (2D) dendrite movement is analyzed. The results demonstrate that the growth of moving dendrites is asymmetric. The growth velocity and falling velocity of the dendrite in the 3D model are faster than that in 2D model, while the simulation result is more realistic than that of the 2D model. When multiple dendrites move, the movement direction of the dendrites will change due to the merging of flow fields and other factors.

scholarly journals CFD-DEM Simulation for the Distribution and Motion Feature of Solid Particles in Single-Channel Pump

Energies ◽  
2020 ◽  
Vol 13 (19) ◽  
pp. 4988 ◽  
Author(s):  
Cheng Tang ◽  
Youn-Jea Kim
Keyword(s):  
Contact Force ◽  
Single Channel ◽  
Numerical Study ◽  
Solid Particles ◽  
Spherical Particles ◽  
Particle Collision ◽  
Future Research ◽  
Motion Feature ◽  
Liquid Flows ◽  
Solid Liquid

Since various foreign bodies can cause clogging and wear in single-channel pumps, considerable attention has been focused on the numerical study of solid-liquid flows in the single-channel pump. However, conventional numerical simulation cannot responsibly assess the significant effect of the particle material properties, inter-particle collision, and size on the pump. In consideration of the particle features and behaviors, the Computational Fluid Dynamics (CFD)-Discrete Element Method (DEM) coupling method was applied for the first time to simulate the solid-liquid flows in a single-channel pump. The results showed that the smaller particles possessed a wider velocity distribution range and velocity peak, while the larger particles exerted a greater contact force. Additionally, the pie-shaped particles had the most severe collisions, and spherical particles had the least in total. Furthermore, the hub and shroud wall suffered a minor contact force, but the blade and volute wall both sustained a considerable contact force. This paper could present some supply data for future research on the optimization of a single-channel pump.

Raman Spectrum Analysis on the Solid–Liquid Boundary Layer of BGO Crystal Growth

2007 ◽  
Vol 24 (7) ◽  
pp. 1898-1900 ◽  
Author(s):  
Zhang Xia ◽  
Yin Shao-Tang ◽  
Wan Song-Ming ◽  
You Jing-Lin ◽  
Chen Hui ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Raman Spectrum ◽  
Crystal Growth ◽  
Spectrum Analysis ◽  
Liquid Boundary ◽  
Solid Liquid ◽  
Liquid Boundary Layer

The Effect of Microwave Sintering Time to PM Aluminum Alloys

2015 ◽  
Vol 754-755 ◽  
pp. 240-244
Author(s):  
M.N. Derman ◽  
Syaza Nabilla Mohd Suhaimi ◽  
Zuraidawani Che Daud
Keyword(s):  
Microwave Sintering ◽  
Microwave Oven ◽  
Solid Particles ◽  
Binding Reaction ◽  
Aluminium Powder ◽  
Sintering Time ◽  
Conventional Sintering ◽  
Rapid Sintering ◽  
Powder Particles ◽  
Solid Liquid

Microwave sintering is new sintering technology method to produce Al alloys. The advantages of this method because of very short sintering time and less production cost compare to conventional sintering. However, the main problems in microwave sintering are required to be controlled sintering time due to rapid sintering mechanism. Therefore the effect of microwave sintering time to PM Aluminium will be studied. The compacted and sintered aluminium powder is placed in a microwave oven at a different period of 5 minutes, 10 minutes, 15 minutes and 20 minutes. Compression of 150 MPa is applied on aluminium powder to form pellets. Palette is shaped to 1cm in diameter and weighs 1g. SiC is placed together with aluminium samples in the microwave for the purpose of absorbing electromagnetic energy and is converted to heat. Results of different period sintering of aluminium pallet production altered physical properties of each sample. For a rapid sintering time, aluminium pallet does not show any binding reaction between powder particles. Whereas, for long microwave sintering period, solid particles phase change into solid-liquid phase caused by the movement and the formation of bonds between particles. Hence, this will be affecting the mechanical properties of the sample material.

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