scholarly journals Experimental and Simulation Research on the Influence of Stirring Parameters on the Distribution of Particles in Cast SiCp/A356 Composites

2017 ◽  
Vol 2017 ◽  
pp. 1-11
Author(s):  
Zhiyong Yang ◽  
Like Pan ◽  
Jianmin Han ◽  
Zhiqiang Li ◽  
Jialin Wang ◽  
...  
Keyword(s):  
Volume Fraction ◽  
Fluid Velocity ◽  
Axial Flow ◽  
Particle Dispersion ◽  
Numerical Results ◽  
Shearing Force ◽  
Simulation Research ◽  
Velocity Magnitude ◽  
Stirring Time ◽  
Good Agreement

Achieving the uniform distribution of reinforcement particles in MMCs is very important for the effect of stirring parameters and the flow action of the melt, which should be known. The effect of stirring parameters on the distribution of SiC particles in SiCp/A356 composites was studied by the experimental and numerical methods in this paper. The experimental results show the SiC distribution with different stirring parameters. In addition, the effects of the fluid velocity and volume fraction of SiC particle at different position of crucible on the SiC distribution were analyzed by numerical simulation. The velocity magnitude, axial velocity, and radial velocity were analyzed to explain theoretically the particle distribution. The shearing force, moments, and stirring power of the stirring rod were simulated based on CFD code. The numerical results show that the stirring temperature is lower, the shearing force is greater, the stirring time is longer, and particle dispersion gets better. On the other hand, the higher the stirring speed is, the more uniform the radial and axial flow are, and the better the particles were dispersed. The numerical results were in good agreement with the experimental data.

Effect of Mechanical Stirring on Microstructural Morphology in Semisolid A356 Alloy

2011 ◽  
Vol 328-330 ◽  
pp. 1149-1152
Author(s):  
Zheng Liu ◽  
Xiao Mei Liu ◽  
Wei Min Mao
Keyword(s):  
Liquidus Temperature ◽  
Volume Fraction ◽  
Solid Volume Fraction ◽  
A356 Alloy ◽  
Shearing Force ◽  
Mechanical Stirring ◽  
Stirring Time ◽  
Microstructural Morphology ◽  
Melt Cooling

The evolution of microstructural morphology in semisolid A356 alloy was researched under the mechanical stirring. The results showed that there was the effect of the stirring time on the microstructural morphology of semisolid A356 alloy, in which the microstructural morphology became better with the stirring time prolonging. There was also the effect of the stirring process on the microstructural morphology, in which the microstructural morphology obtained from the melt cooling to the reset solid volume fraction to start stirring was coarser than that obtained from the stirring above the liquidus temperature, but the microstructural morphology rapidly changes under the shearing force.

On the maximal spreading of impacting compound drops

2018 ◽  
Vol 854 ◽  
Author(s):  
H.-R. Liu ◽  
C.-Y. Zhang ◽  
P. Gao ◽  
X.-Y. Lu ◽  
H. Ding
Keyword(s):  
Flow Regime ◽  
Weber Number ◽  
Volume Fraction ◽  
Numerical Results ◽  
Diffuse Interface ◽  
Spreading Dynamics ◽  
The One ◽  
Compound Drops ◽  
The Impact ◽  
Good Agreement

We numerically study the impact of a compound drop on a hydrophobic substrate using a ternary-fluid diffuse-interface method, aiming to understand how the presence of the inner droplet affects the spreading dynamics and maximal spreading of the compound drop. First, it is interesting to see that the numerical results for an impacting pure drop agree well with the universal rescaling of maximal spreading ratio proposed by Lee et al. (J. Fluid Mech., vol. 786, 2016, R4). Second, two flow regimes have been identified for an impacting compound drop: namely jammed spreading and joint rim formation. The maximal spreading ratio of the compound drop is found to depend on the volume fraction of the inner droplet $\unicode[STIX]{x1D6FC}$, the surface tension ratio $\unicode[STIX]{x1D6FE}$, the Weber number and the flow regime. Moreover, we propose a universal rescaling of maximal spreading ratio for compound drops, by integrating the one for pure drops with a corrected Weber number that takes $\unicode[STIX]{x1D6FC}$, $\unicode[STIX]{x1D6FE}$ and the flow regime into account. The predictions of the universal rescaling are in good agreement with the numerical results for impacting compound drops.

Numerical Study of Liquid-Liquid Vertical Dispersed Flows

2012 ◽  
Author(s):  
Kofi Freeman K. Adane ◽  
Syed Imran A. Shah ◽  
R. Sean Sanders
Keyword(s):  
Turbulent Flows ◽  
Volume Fraction ◽  
Numerical Study ◽  
Continuous Phase ◽  
Numerical Results ◽  
Mean Velocity ◽  
Ansys Cfx ◽  
Oil In Water ◽  
Dispersed Flows ◽  
Good Agreement

Numerical simulations of liquid-liquid dispersed flow in a vertical pipe (38mm) have been carried out using the two-fluid approach implemented in a commercial CFD code, ANSYS CFX. A dispersion of oil in water (where water is the continuous phase) was studied. Both fluids were considered as turbulent flows. The k-ε model was used for the continuous phase, with the eddy viscosity of the dispersed phase estimated from that of the continuous phase. A comparison of the present numerical results with previous experimental and numerical results in terms of volume fraction, mean velocity and turbulent kinetic energy is discussed. In general, good agreement between the simulation results and experimental measurements was observed.

scholarly journals Heat Treatment Evaluation for the Camshafts Production of ADI Low Alloyed with Vanadium

Metals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1036
Author(s):  
Eduardo Colin García ◽  
Alejandro Cruz Ramírez ◽  
Guillermo Reyes Castellanos ◽  
José Federico Chávez Alcalá ◽  
Jaime Téllez Ramírez ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Tensile Strength ◽  
Ductile Iron ◽  
Volume Fraction ◽  
Energy Impact ◽  
Treatment Conditions ◽  
Mold Casting ◽  
Grade 3 ◽  
Good Agreement

Ductile iron camshafts low alloyed with 0.2 and 0.3 wt % vanadium were produced by one of the largest manufacturers of the ductile iron camshafts in México “ARBOMEX S.A de C.V” by a phenolic urethane no-bake sand mold casting method. During functioning, camshafts are subject to bending and torsional stresses, and the lobe surfaces are highly loaded. Thus, high toughness and wear resistance are essential for this component. In this work, two austempering ductile iron heat treatments were evaluated to increase the mechanical properties of tensile strength, hardness, and toughness of the ductile iron camshaft low alloyed with vanadium. The austempering process was held at 265 and 305 °C and austempering times of 30, 60, 90, and 120 min. The volume fraction of high-carbon austenite was determined for the heat treatment conditions by XRD measurements. The ausferritic matrix was determined in 90 min for both austempering temperatures, having a good agreement with the microstructural and hardness evolution as the austempering time increased. The mechanical properties of tensile strength, hardness, and toughness were evaluated from samples obtained from the camshaft and the standard Keel block. The highest mechanical properties were obtained for the austempering heat treatment of 265 °C for 90 min for the ADI containing 0.3 wt % V. The tensile and yield strength were 1200 and 1051 MPa, respectively, while the hardness and the energy impact values were of 47 HRC and 26 J; these values are in the range expected for an ADI grade 3.

Permeability in the Mushy Zone

2010 ◽  
Vol 649 ◽  
pp. 399-408 ◽  
Author(s):  
R.G. Erdmann ◽  
D.R. Poirier ◽  
A.G. Hendrick
Keyword(s):  
Mushy Zone ◽  
Volume Fraction ◽  
Primary Dendrite ◽  
Fluid Velocity ◽  
Interdendritic Liquid ◽  
Creeping Flow ◽  
Liquid Region ◽  
Local Volume ◽  
Local Volume Fraction ◽  
Deterministic Function

When modeled at macroscopic length scales, the complex dendritic network in the solid-plus-liquid region of a solidifying alloy (the “mushy zone”) has been modeled as a continuum based on the theory of porous media. The most important property of a porous medium is its permeability, which relates the macroscopic pressure gradient to the throughput of fluid flow. Knowledge of the permeability of the mushy zone as a function of the local volume-fraction of liquid and other morphological parameters is thus essential to successfully modeling the flow of interdendritic liquid during alloy solidification. In current continuum models, the permeability of the mushy zone is given as a deterministic function of (1) the local volume fraction of liquid and (2) a characteristic length scale such as the primary dendrite arm spacing or the reciprocal of the specific surface area of the solid-liquid interface. Here we first provide a broad overview of the experimental data, mesoscale numerical flow simulations, and resulting correlations for the deterministic permeability of both equiaxed and columnar mushy zones. A extended view of permeability in mushy zones which includes the stochastic nature of permeability is discussed. This viewpoint is the result of performing extensive numerical simulations of creeping flow through random microstructures. The permeabilities obtained from these simulations are random functions with spatial autocorrelation structures, and variations in the local permeability are shown to have dramatic effects on the flow patterns observed in such microstructures. Specifically, it is found that “lightning-like” patterns emerge in the fluid velocity and that the flows in such geometries are strongly sensitive to small variations in the solid structure. We conclude with a comparison of deterministic and stochastic permeabilities which suggests the importance of incorporating stochastic descriptions of the permeability of the mushy zone in solidification modeling.

Estimation of Interlayer Thickness in Inorganic Particulate-Filled Polymer Composites

2011 ◽  
Vol 24 (6) ◽  
pp. 777-788 ◽  
Author(s):  
J.Z. Liang
Keyword(s):  
Polymer Composites ◽  
Volume Fraction ◽  
Particle Diameter ◽  
Interfacial Structure ◽  
Interlayer Thickness ◽  
Filled Polymer ◽  
Mechanical And Physical Properties ◽  
The Relationship ◽  
Good Agreement

The structure of the interlayer between matrix and inclusions affect directly the mechanical and physical properties of inorganic particulate-filled polymer composites. The interlayer thickness is an important parameter for characterization of the interfacial structure. The effects of the interlayer between the filler particles and matrix on the mechanical properties of polymer composites were analyzed in this article. On the basis of a simplified model of interlayer, an expression for estimating the interlayer thickness ([Formula: see text]) was proposed. In addition, the relationship between the [Formula: see text] and the particle size and its concentration was discussed. The results showed that the calculations of the [Formula: see text] and thickness/particle diameter ratio ([Formula: see text]) increased nonlinearly with an increase of the volume fraction of the inclusions. Moreover, the predictions of [Formula: see text] and the relevant data reported in literature were compared, and good agreement was found between them.

Study on Dynamic Recrystallization Behavior in Deformed Austenite of 52100 Steel by Using JMAK-Model

2013 ◽  
Vol 275-277 ◽  
pp. 1833-1837
Author(s):  
Ke Lu Wang ◽  
Shi Qiang Lu ◽  
Xin Li ◽  
Xian Juan Dong
Keyword(s):  
Grain Size ◽  
Dynamic Recrystallization ◽  
Hot Deformation ◽  
Volume Fraction ◽  
True Strain ◽  
Strain And Strain Rate ◽  
Average Grain Size ◽  
Dynamic Recrystallization Behavior ◽  
Simulation And Experiment ◽  
Good Agreement

A Johnson-Mehl-Avrami-Kolmogorov (JMAK)-model was established for dynamic recrystallization in hot deformation process of 52100 steel. The effects of hot deformation temperature, true strain and strain rate on the microstructural evolution of the steel were physically studied by using Gleeble-1500 thermo-mechanical simulator and the experimental results were used for validation of the JMAK-model. Through simulation and experiment, it is found that the predicted results of DRX volume fraction, DRX grain size and average grain size are in good agreement with the experimental ones.

The Estimation of Thermal Conductivity for Alumina-Epoxy Composite Material with High Filling Volume Fraction

2014 ◽  
Vol 918 ◽  
pp. 21-26
Author(s):  
Chen Kang Huang ◽  
Yun Ching Leong
Keyword(s):  
Thermal Conductivity ◽  
Composite Material ◽  
Composite Materials ◽  
Physical Model ◽  
Electron Scattering ◽  
Volume Fraction ◽  
Epoxy Composite ◽  
The Matrix ◽  
Transport Theorem ◽  
Good Agreement

In this study, the transport theorem of phonons and electrons is utilized to create a model to predict the thermal conductivity of composite materials. By observing or assuming the dopant displacement in the matrix, a physical model between dopant and matrix can be built, and the composite material can be divided into several regions. In each region, the phonon or electron scattering caused by boundaries, impurities, or U-processes was taken into account to calculate the thermal conductivity. The model is then used to predict the composite thermal conductivity for several composite materials. It shows a pretty good agreement with previous studies in literatures. Based on the model, some discussions about dopant size and volume fraction are also made.

scholarly journals CuO–Water Nanofluid Magnetohydrodynamic Natural Convection inside a Sinusoidal Annulus in Presence of Melting Heat Transfer

2017 ◽  
Vol 2017 ◽  
pp. 1-9 ◽  
Author(s):  
M. Sheikholeslami ◽  
R. Ellahi ◽  
C. Fetecau
Keyword(s):  
Magnetic Field ◽  
Heat Transfer ◽  
Natural Convection ◽  
Hartmann Number ◽  
Volume Fraction ◽  
Melting Heat ◽  
Melting Heat Transfer ◽  
Limiting Case ◽  
Good Agreement ◽  
Melting Parameter

Impact of nanofluid natural convection due to magnetic field in existence of melting heat transfer is simulated using CVFEM in this research. KKL model is taken into account to obtain properties of CuO–H2O nanofluid. Roles of melting parameter (δ), CuO–H2O volume fraction (ϕ), Hartmann number (Ha), and Rayleigh (Ra) number are depicted in outputs. Results depict that temperature gradient improves with rise of Rayleigh number and melting parameter. Nusselt number detracts with rise of Ha. At the end, a comparison as a limiting case of the considered problem with the existing studies is made and found in good agreement.

On Wall Effects in Cavity Flows

1984 ◽  
Vol 28 (01) ◽  
pp. 70-75
Author(s):  
C. C. Hsu
Keyword(s):  
Numerical Results ◽  
Cavity Flows ◽  
Two Dimensional ◽  
Wall Effects ◽  
Free Jet ◽  
Theoretical Predictions ◽  
Experimental Findings ◽  
Good Agreement

Simple wall correction rules for two-dimensional and nearly two-dimensional cavity flows in closed or free jet water tunnels, based on existing linearized analyses, are made. Numerical results calculated from these expressions are compared with existing experimental findings. The present theoretical predictions are, in general, in good agreement with data.

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