Numerical Study on Momentum Transfer Between Droplets and Carrier-Phase in Wave-Type Plate Separators

2017 ◽  
Author(s):  
Li Yuzheng ◽  
Liu Qianfeng ◽  
Bo Hanliang
Keyword(s):  
Momentum Transfer ◽  
Carrier Phase ◽  
Volume Fraction ◽  
Numerical Study ◽  
Euler Method ◽  
Coupling Method ◽  
Low Velocity ◽  
Wave Type ◽  
The One ◽  
Different Diameters

The steam flow is simulated by FLUENT. The Lagrange-Euler method is used to simulate the droplet-laden flow in wave-type separators. Two-way coupling method is used to study the influence of the momentum transfer between droplets and carrier-phase in wave-type plate separators. A group of the trajectories of droplets with different diameters are performed in wave-type plate separator flow field. The result shows that the momentum transfer has tiny impact on the behaviors of droplets in a low velocity flow. However, the momentum transfer affects the behaviors of droplets more significantly with rising flow velocity. The one-way coupling method overestimates the diffusion of droplets. In addition, the momentum transfer affects the total pressure loss more significantly with rising volume fraction. The conclusion verifies the importance of the momentum transfer in droplet-laden flows, which could be used to simulate the behavior of droplets moving in a separator.

scholarly journals Numerical investigation of a moisture wave-type vane separator

2019 ◽  
Vol 140 ◽  
pp. 06011
Author(s):  
Ivan Kasatkin ◽  
Mikle Egorov ◽  
Nikolay Rakov
Keyword(s):  
Two Phase Flow ◽  
Numerical Study ◽  
Euler Method ◽  
Saturated Steam ◽  
Phase Flow ◽  
Water Droplets ◽  
Wave Type ◽  
Two Phase ◽  
Separation Processes ◽  
Drainage Channels

This study aims to determine the appropriate method for modeling separation processes in wave-type moisture vane separators and to analyze possible design improvements of the typical wave-type vane separator using numerical simulation methods. It discusses conditions of the secondary droplets generation phenomena. The applicability of the particle transport method for modeling the working process in wave-type vane separators is confirmed. The study explores the water droplets distribution pattern in the dispersed two-phase flow of a separator. A numerical study of the workflow in the typical steam-water separator with wave-type vanes was carried out. A dispersed two-phase flow in a separator is modelled as two separate flows. Dry saturated steam is considered as a continuous medium using the Euler method; the liquid phase is represented as a stream of water droplets described by the Lagrange method. Authors propose an option of modernization of the separator design applying three drainage channels on the path of small droplets.

scholarly journals Effect of Nanostructure on Thermal Conductivity of Nanofluids

2015 ◽  
Vol 2015 ◽  
pp. 1-7 ◽  
Author(s):  
Saba Lotfizadeh ◽  
Themis Matsoukas
Keyword(s):  
Thermal Conductivity ◽  
Colloidal Particles ◽  
Volume Fraction ◽  
Numerical Study ◽  
Hollow Spheres ◽  
Structural Features ◽  
Solid Particles ◽  
Spherical Particles ◽  
Colloidal Gel ◽  
The One

The presence of colloidal particles is known to increase the thermal conductivity of base fluids. The shape and structure of the solid particles are important in determining the magnitude of enhancement. Spherical particles—the only shape for which analytic theories exist—produce the smallest enhancement. Nonspherical shapes, including clusters formed by colloidal aggregation, provide substantially higher enhancements. We conduct a numerical study of the thermal conductivity of nonspherical structures dispersed in a liquid at fixed volume fraction in order to identify structural features that promote the conduction of heat. We find that elongated structures provide high enhancements, especially if they are long enough to create a solid network (colloidal gel). Cross-linking further enhances thermal transport by directing heat in multiple directions. The most efficient structure is the one formed by hollow spheres consisting of a solid shell and a core filled by the fluid. In both dispersed and aggregated forms, hollow spheres provide enhancements that approach the theoretical limit set by Maxwell’s theory.

Numerical Study of a Non-Linear Model for the Heat Flux Vector for Granular Materials

2012 ◽  
Author(s):  
Hyunjin Yang ◽  
Nadine Aubry ◽  
Mehrdad Massoudi
Keyword(s):  
Heat Flux ◽  
Granular Materials ◽  
Volume Fraction ◽  
Numerical Study ◽  
Constitutive Relations ◽  
Flux Vector ◽  
Heat Flux Vector ◽  
Non Linear ◽  
Effects Of Radiation ◽  
The One

The two important constitutive relations needed for the study of flow and heat transfer in granular materials, where the effects of radiation are ignored, are the stress tensor and the heat flux vector. Massoudi [1, 2] derived a constitutive model that reflects the dependence of the heat flux vector on the temperature gradient, the density gradient and the velocity gradient, in an appropriate frame-invariant formulation. In this paper we use a simplified version of this model and consider the one dimensional fully developed flow of granular materials down a heated inclined plane, subject to a constant temperature boundary condition. The equations are made dimensionless and a parametric study is performed in order to examine the effects of the additional parameters on the heat flux vector. The derived governing equations are coupled non-linear second order ordinary differential equations which are solved numerically and the results are shown for the temperature, volume fraction and velocity profiles.

Numerical Study on the Impact of Cooling Rate on the Solidification of Al-Bi Hypermonotectic Alloys

2017 ◽  
Vol 727 ◽  
pp. 111-116
Author(s):  
Zhi Qiang Kang ◽  
Xue Yang ◽  
Guo Hui Feng ◽  
Lin Zhang
Keyword(s):  
Cooling Rate ◽  
Volume Fraction ◽  
Numerical Study ◽  
Solidification Rate ◽  
Average Diameter ◽  
Euler Method ◽  
Solidification Structure ◽  
Diffusional Growth ◽  
Gravity Settling ◽  
The Impact

A numerical model describing the liquid-liquid phase transformation of the nucleation, the diffusional growth, Ostwald coarsening and macro-transport phenomena was established based on Euler-Euler method. The microstructure development of Al-Bi alloys in different solidification rate has been simulated by coupling the calculated temperature and velocity fields with the kinetic equation which controls the microstructure evolution. The results showed that average diameter difference of L2 phase droplets between top and bottom of samples in low cooling rate increased by 151 % than in high cooling speed and the maximum volume fraction of the droplets at the bottom of the sample in low cooling rate much higher than in high cooling rate. Analysis that the bigger cooling rate can shorten the action time which caused by gravity settling and collisions coagulation of the droplets, and then improves the macrosegregation of solidification structure in favor of uniform distribution of the solidification structure.

Preparation of Electron Transparent Metal-Matrix Composites

1968 ◽  
Vol 26 ◽  
pp. 334-335 ◽  
Author(s):  
M. R. Pinnel ◽  
A. Lawley
Keyword(s):  
Stainless Steel ◽  
Load Transfer ◽  
Volume Fraction ◽  
Steel Wire ◽  
Initial Step ◽  
Interfacial Region ◽  
Matrix Composites ◽  
Specific Test ◽  
The Matrix ◽  
The One

Numerous phenomenological descriptions of the mechanical behavior of composite materials have been developed. There is now an urgent need to study and interpret deformation behavior, load transfer, and strain distribution, in terms of micromechanisms at the atomic level. One approach is to characterize dislocation substructure resulting from specific test conditions by the various techniques of transmission electron microscopy. The present paper describes a technique for the preparation of electron transparent composites of aluminum-stainless steel, such that examination of the matrix-fiber (wire), or interfacial region is possible. Dislocation substructures are currently under examination following tensile, compressive, and creep loading. The technique complements and extends the one other study in this area by Hancock.The composite examined was hot-pressed (argon atmosphere) 99.99% aluminum reinforced with 15% volume fraction stainless steel wire (0.006″ dia.).Foils were prepared so that the stainless steel wires run longitudinally in the plane of the specimen i.e. the electron beam is perpendicular to the axes of the wires. The initial step involves cutting slices ∼0.040″ in thickness on a diamond slitting wheel.

scholarly journals Numerical Study on an Interface Compression Method for the Volume of Fluid Approach

Fluids ◽  
2021 ◽  
Vol 6 (2) ◽  
pp. 80
Author(s):  
Yuria Okagaki ◽  
Taisuke Yonomoto ◽  
Masahiro Ishigaki ◽  
Yoshiyasu Hirose
Keyword(s):  
Linear Theory ◽  
Volume Fraction ◽  
Numerical Study ◽  
Volume Of Fluid ◽  
Interfacial Wave ◽  
Validation Process ◽  
Two Phase ◽  
Numerical Diffusion ◽  
Mesh Resolution ◽  
Water Reactors

Many thermohydraulic issues about the safety of light water reactors are related to complicated two-phase flow phenomena. In these phenomena, computational fluid dynamics (CFD) analysis using the volume of fluid (VOF) method causes numerical diffusion generated by the first-order upwind scheme used in the convection term of the volume fraction equation. Thus, in this study, we focused on an interface compression (IC) method for such a VOF approach; this technique prevents numerical diffusion issues and maintains boundedness and conservation with negative diffusion. First, on a sufficiently high mesh resolution and without the IC method, the validation process was considered by comparing the amplitude growth of the interfacial wave between a two-dimensional gas sheet and a quiescent liquid using the linear theory. The disturbance growth rates were consistent with the linear theory, and the validation process was considered appropriate. Then, this validation process confirmed the effects of the IC method on numerical diffusion, and we derived the optimum value of the IC coefficient, which is the parameter that controls the numerical diffusion.

Proton radiography of explosively dispersed metal particles with varying volume fraction and varying carrier phase

Shock Waves ◽  
2021 ◽  
Author(s):  
K. T. Hughes ◽  
J. J. Charonko ◽  
K. P. Prestridge ◽  
N. H. Kim ◽  
R. T. Haftka ◽  
...  
Keyword(s):  
Carrier Phase ◽  
Volume Fraction ◽  
Metal Particles ◽  
Proton Radiography

A Parametric Numerical Study of Radiative Transfer in Thermotropic Materials

2013 ◽  
Author(s):  
Adam C. Gladen ◽  
Susan C. Mantell ◽  
Jane H. Davidson
Keyword(s):  
Particle Size ◽  
Radiative Transfer ◽  
Optical Thickness ◽  
Parametric Study ◽  
Volume Fraction ◽  
Numerical Study ◽  
Anisotropic Scattering ◽  
Index Of Refraction ◽  
Spherical Particles ◽  
Size Parameter

A thermotropic material is modeled as an absorbing, thin slab containing anisotropic scattering, monodisperse, spherical particles. Monte Carlo ray tracing is used to solve the governing equation of radiative transfer. Predicted results are validated by comparison to the measured normal-hemispherical reflectance and transmittance of samples with various volume fraction and relative index of refraction. A parametric study elucidates the effects of particle size parameter, scattering albedo, and optical thickness on the normal-hemispherical transmittance, reflectance, and absorptance. The results are interpreted for a thermotropic material used for overheat protection of a polymer solar absorber. For the preferred particle size parameter of 2, the optical thickness should be less than 0.3 to ensure high transmittance in the clear state. To significantly reduce the transmittance and increase the reflectance in the translucent state, the optical thickness should be greater than 2.5 and the scattering albedo should be greater than 0.995. For optical thickness greater than 5, the reflectance is asymptotic and any further reduction in transmittance is through increased absorptance. A case study is used to illustrate how the parametric study can be used to guide the design of thermotropic materials. Low molecular weighted polyethylene in poly(methyl methacrylate) is identified as a potential thermotropic material. For this material and a particle radius of 200 nm, it is determined that the volume fraction and thickness should equal 10% and 1 mm, respectively.

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