scholarly journals Experimental Study of the Water-Sediment Two-Phase Seepage Characteristics in Rock Fractures and the Influencing Factors

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-14
Author(s):  
Kui Di ◽  
Ming Li ◽  
Xianbiao Mao ◽  
Zhanqing Chen ◽  
Lianying Zhang ◽  
...  
Keyword(s):  
Particle Size ◽  
Pressure Gradient ◽  
Volume Fraction ◽  
Water Inrush ◽  
Experimental System ◽  
Sand Particle ◽  
Two Phase ◽  
Absolute Value ◽  
The Absolute ◽  
Seepage Characteristics

The water-sediment two-phase seepage in coarse fractures is one of the major factors to trigger mine water inrush disasters. Based on seepage mechanics theory, a mechanical model of the water-sediment two-phase seepage in coarse fractures was established. An experimental system was also developed to study the seepage characteristics under various conditions. The relationships between the absolute value of the pressure gradient and the seepage velocity were analyzed during the test process. The nonlinear characteristics of the seepage test were revealed. In addition, variation laws of the absolute value of the pressure gradient with the sand volume fraction and the sand particle size were illustrated, which were related to the loss of pressure during the particle movement. The impacts of the sand volume fraction and the sand particle size on the equivalent fluidity and β -factor of non-Darcy flow were discussed and analyzed. It was determined that the local turbulence was the main reason for the change of nonlinear variation characteristics of seepage parameters.

scholarly journals Permeability Characteristics of Water-Sand Seepage in Fracture by Experiment

2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Yu Liu ◽  
Shuncai Li ◽  
Wei Li ◽  
Zhihao Luo ◽  
Liming Wu ◽  
...  
Keyword(s):  
Particle Size ◽  
Water Inrush ◽  
Great Influence ◽  
Side Wall ◽  
Hysteresis Curve ◽  
Sand Particle ◽  
Type I ◽  
Permeability Characteristics ◽  
Type Iv ◽  
Seepage Characteristics

Studies on the seepage characteristics of water-sand cracks are of great significance to reveal the mechanisms of water and sand inrush. Using a self-made water-sand fracture seepage test instrument, a water-sand seepage test was carried out, and the permeability of water and sand in the fracture was determined. The hysteresis characteristics of water-sand flow in the fracture were obtained after the required permeability was attained. The results show that the hysteresis curve changes from type I to type IV with the increase in sand particle size and concentration. The hysteresis parameters are described by the maximum hysteresis Gp ∗ and the hysteresis area S, both of which show an increasing trend with the increase in sand particle size and concentration; however, this increase is not synchronous. The average velocity and turbulent kinetic energy distribution of the water-sand fluid on the fracture cross section are greatly affected by the particle size and concentration of the volume of sand. This study can provide a reference for further study of water inrush from a shallow coal seam. Through simulation, it is found that the particle size has a great influence on the seepage velocity, and the influence near the side wall surface is greater than that in the middle position.

scholarly journals Experimental Investigation of Water-Sand Mixed Fluid Initiation and Migration in Filling Fracture Network during Water Inrush

2021 ◽  
Vol 2021 ◽  
pp. 1-20
Author(s):  
Bin Yang ◽  
Tianhong Yang
Keyword(s):  
Particle Size ◽  
Critical Velocity ◽  
Network Flow ◽  
Water Inrush ◽  
Functional Relation ◽  
Flow Characteristics ◽  
Fracture Network ◽  
Nonlinear Flow ◽  
Two Phase ◽  
And Migration

For water inrush induced by fracture network flow, the critical velocity of the incipient motion of sand particles was obtained, and the functional relation between critical velocity and particle size was established through a series of tests on the nonlinear flow characteristics of a filling fracture network. The influence of the particle size distribution, hydrodynamic force, and geometric features of the fracture network on the characteristics of particle loss; distribution laws; and water-sand, two-phase migration was also explored. Moreover, the interactions amongst water, movable particles, the surface of the skeleton, and fracture walls, and the formation mechanism of the flow channel were qualitatively analyzed. In addition, the change rules of the mass loss characteristics and porosity of the samples with time were tested successfully. The calculation methods of the permeability and non-Darcy factor of the filling fracture network were also determined.

The Investigation of the Kinetic Energy of Slug in a Horizontal Channel Using VOF Method

2018 ◽  
Author(s):  
Nariman Ashrafi ◽  
Mohammad Reza Ansari ◽  
Armin Chegini ◽  
Ali Sadeghi
Keyword(s):  
Kinetic Energy ◽  
Pressure Gradient ◽  
Cross Section ◽  
Volume Fraction ◽  
Rectangular Cross Section ◽  
Vof Method ◽  
Experimental Results ◽  
Two Phase ◽  
Trapped Air ◽  
Helmholtz Condition

In this article, two-phase slug regime in a duct with rectangular cross-section is investigated numerically, using the volume of fluid (VOF) method. Equations of mass, momentum and advection of volume fraction are solved accompanying k-∈ realizable turbulence equations. To ensure the creditability, numerical results have been compared with experimental results using same geometry. With occurrence of instability in the entrance of duct, Kelvin-Helmholtz condition satisfies and with increasing instability, slug phenomenon occurs. With closing the cross-section of duct, slug causes pressure gradient in it. Trapped air behind a slug transfers the momentum and increases the kinetic energy of slug. In this research the kinetic energy of a slug is investigated.

Experimental Investigation of Pressure Drop in One Phase Flow, Particle-Liquid Two-Phase Flow, and Porous Media Consisting of the Same Particle Size

2009 ◽  
Vol 283-286 ◽  
pp. 599-603
Author(s):  
Hikmet Ş. Aybar ◽  
Mohsen Sharifpur ◽  
Roozbeh Vaziri
Keyword(s):  
Particle Size ◽  
Porous Media ◽  
Pressure Gradient ◽  
Two Phase Flow ◽  
Water Pressure ◽  
Spherical Particles ◽  
Phase Flow ◽  
Two Phase ◽  
The One ◽  
Flow Particle

Many researches have performed some studies about pressure gradient in the one phase flow, particle-liquid two-phase flow and porous media. However, there is no any report about interaction among them. In this study, this interaction idea is developed by using the same particle size for particle-liquid two-phase flow and porous media. For the experimental study, an apparatus is designed, and at the first step one phase water pressure gradient is investigated, next in the further steps, little by little spherical particles are added to the cycle till accumulation of the particles did not allow any movement to the particles (i.e. porous media occur), and after that well pack porous media is investigated. The results confirm the relation between pressure gradient over mass flow rate in the one phase flow, particle-liquid two-phase flow and porous media obeys as a parabolic curve.

Numeration Simulation of Solid-Liquid Two-Phase Flow in Centrifugal Sewerage Pump

2010 ◽  
Vol 44-47 ◽  
pp. 345-348 ◽  
Author(s):  
Jian Hua Liu ◽  
Ming Yi Zhu
Keyword(s):  
Particle Size ◽  
Solid Particle ◽  
Working Condition ◽  
Two Phase Flow ◽  
Volume Fraction ◽  
Phase Flow ◽  
Operation Condition ◽  
Two Phase ◽  
And Performance ◽  
Solid Liquid

By Means of Fluent 6.3，the paper simulated the solid-liquid two-phase flow to a centrifugal sewerage pump，using Eulerian Mixture Model under different working condition and different particle size. The simulation draws some conclusion on distributive rules of solid particle inside impeller passage. The results for this simulation were as following: Distributive rules of solid particle inside impeller passage mainly relate to particle size. Meanwhile，the volume fraction of particles and operation condition have influence on distributive rules of solid particle. The simulated results can explain commendably that attrition took place inside pump passage when pump transported solid-liquid two-phase flow. Meanwhile，the simulated results have reference price to improve the design for pump and performance of pump.

scholarly journals Study on Two-Phase Fluid-Solid Coupling Characteristics in Local-Saturated Zone of Subgrade Considering the Effect of Fine Particles Migration

2020 ◽  
Author(s):  
Yu Ding ◽  
Jia-sheng Zhang ◽  
Yu Jia ◽  
Xiao-bin Chen ◽  
Xuan Wang ◽  
...  
Keyword(s):  
Mathematical Model ◽  
Fine Particles ◽  
Volume Fraction ◽  
Solid Skeleton ◽  
Saturated Zone ◽  
Two Phase ◽  
Maximum Value ◽  
Fluid Seepage ◽  
Seepage Characteristics ◽  
Phase Fluid

The fluid seepage in local-saturated zone of subgrade promotes the migration of fine particles in the filler, resulting in the change of pore structure and morphology of the filler and the deformation of solid skeleton, which affects the fluid seepage characteristics. Repeatedly, the muddy interlayer, mud pumping and other diseases are finally formed. Based on the theory of two-phase seepage, the theory of porous media seepage, and the principle of effective stress in porous media, a two-phase fluid-solid coupling mathematical model in local-saturated zone of subgrade considering the effect of fine particles migration is established. The mathematical model is numerically calculated with the software COMSOL Multiphysics○R, the two-phase seepage characteristics and the deformation characteristics of the solid skeleton in local-saturated zone of the subgrade are studied. The research results show that due to the continuous erosion and migration of fine particles in local-saturated zone of the subgrade, the volume fraction of fine particles first increases then decreases and finally becomes stable with the increase of time. And the volume fraction of fine particles for the upper part of the subgrade is larger than that for the lower part of the subgrade. The porosity, the velocity of fluid, the velocity of fine particles, and the permeability show a trend of increasing first and then stabilizing with time; the pore water pressure has no significant changes with time. The vertical displacement increase first and then decrease slightly with the increase of time, and finally tend to be stable. For a filler with a larger initial volume fraction of fine particles, the maximum value of the volume fraction of fine particles caused by fluid seepage is larger, and the time required to reach the maximum value is shorter. It can be concluded that in actual engineering, the volume fraction of fine particles in the subgrade filler should be minimized on the premise that the filler gradation meets the requirements of the specification.

Transport of Cu–H2O nanofluid through a channel with wavy walls under velocity slip and connective boundary conditions

2016 ◽  
Vol 09 (02) ◽  
pp. 1650022 ◽  
Author(s):  
F. M. Abbasi ◽  
T. Hayat ◽  
A. Alsaedi
Keyword(s):  
Boundary Conditions ◽  
Pressure Gradient ◽  
Axial Velocity ◽  
Numerical Solutions ◽  
Volume Fraction ◽  
Pressure Rise ◽  
Velocity Slip ◽  
Fluid Temperature ◽  
Two Phase ◽  
Convective Boundary

Present study examines the mixed convective peristaltic transport of Cu–H2O nanofluid with velocity slip and convective boundary conditions. Analysis is performed using the two-phase model of the nanofluid. Viscous dissipation and heat generation/absorption effects are also taken into account. Problem is formulated using the long wavelength and low Reynolds number approach. Numerical solutions for the pressure rise per wavelength, pressure gradient, axial velocity, temperature and heat transfer rate at the boundary are obtained and studied through graphs. Results show that the area of peristaltic pumping decreases with an increase in the nanoparticles volume fraction. Increase in the velocity slip parameter shows an increase of the pressure gradient in the occluded part of the channel. Further, addition of copper nanoparticles reduces both the axial velocity and temperature of the base fluid. Temperature of the nanofluid also decreases sufficiently for an increase in the value of Biot number.

scholarly journals Study on Two-Phase Fluid-Solid Coupling Characteristics in Saturated Zone of Subgrade Considering the Effects of Fine Particles Migration

2020 ◽  
Vol 10 (21) ◽  
pp. 7539
Author(s):  
Yu Ding ◽  
Jia-sheng Zhang ◽  
Yu Jia ◽  
Xiao-bin Chen ◽  
Xuan Wang ◽  
...  
Keyword(s):  
Mathematical Model ◽  
Fine Particles ◽  
Volume Fraction ◽  
Solid Skeleton ◽  
Saturated Zone ◽  
Two Phase ◽  
Maximum Value ◽  
Fluid Seepage ◽  
Seepage Characteristics ◽  
Phase Fluid

The fluid seepage in saturated zone of subgrade promotes the migration of fine particles in the filler, resulting in the change of pore structure and morphology of the filler and the deformation of solid skeleton, which affects the fluid seepage characteristics. Repeatedly, the muddy interlayer, mud pumping, and other diseases are finally formed. Based on the theory of two-phase seepage, the theory of porous media seepage, and the principle of effective stress in porous media, a two-phase fluid-solid coupling mathematical model in saturated zone of subgrade considering the effects of fine particles migration is established. The mathematical model is numerically calculated with the software COMSOL Multiphysics®. The two-phase seepage characteristics and the deformation characteristics of the solid skeleton in saturated zone of the subgrade are studied. The research results show that the volume fraction of fine particles first increases then decreases and finally becomes stable with the increase of time, due to the continuous erosion and migration of fine particles in saturated zone of the subgrade. The volume fraction of fine particles for the upper part of the subgrade is larger than that for the lower part of the subgrade. The porosity, the velocity of fluid, the velocity of fine particles, and the permeability show a trend of increasing first and then stabilizing with time; the pore water pressure has no significant changes with time. The vertical displacement increases first and then decreases slightly with the increase of time, and finally tends to be stable. For the filler with a larger initial volume fraction of fine particles, the maximum value of the volume fraction of fine particles caused by fluid seepage is larger, and the time required to reach the maximum value is shorter. It can be concluded that the volume fraction of fine particles in the subgrade filler should be minimized on the premise that the filler gradation meets the requirements of the specification in actual engineering.

Composition Fluctuations in the Ostwald Ripening

2008 ◽  
Vol 277 ◽  
pp. 187-192
Author(s):  
G.V. Lutsenko ◽  
Andriy Gusak
Keyword(s):  
Computer Simulation ◽  
Particle Size ◽  
Large Volume ◽  
Ostwald Ripening ◽  
Volume Fraction ◽  
Size Distributions ◽  
Particle Size Distributions ◽  
Two Phase ◽  
Large Volume Fraction ◽  
Composition Fluctuations

The Ostwald ripening of a two-phase binary alloy has been considered for case of “large” volume fraction of precipitating phase. The approach is proposed in which the composition fluctuations into the vicinity of particles are considered. In this approach the evolution of particle size distributions is analyzed using the computer simulation.

scholarly journals Experimental Study of Hysteresis Characteristics of Water-Sediment Mixture Seepage in Rock Fractures

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Lili Cao ◽  
Pu Zhang ◽  
Jiazhi Zhang ◽  
Gang Lin ◽  
Izhar Mithal Jiskani ◽  
...  
Keyword(s):  
Particle Size ◽  
Coal Mine ◽  
Mass Concentration ◽  
Water Inrush ◽  
Sand Particle ◽  
Rock Fractures ◽  
Fracture Opening ◽  
Sediment Mixture ◽  
And Control ◽  
Hysteresis Characteristics

The hysteresis of water-sediment mixture seepage in rock fractures is one of the critical factors which affect the determination of the timing of coal mine water inrush disasters prevention and control. In this paper, a mechanical model was established to study the hysteresis whose criteria were also put forward. The area of the hysteresis loop and the maximum pressure gradient were selected as characterization parameters of hysteresis. On this basis, an experimental system was established to study influences of different sand particle size, sand mass concentration, and fracture opening on water-sediment mixture seepage in rock fractures. The results indicated that the increase in the sand particle size and sand mass concentration could effectively enhance hysteresis characteristics of specimen fractures. While hysteresis characteristics decreased significantly with the increase of fracture opening. The research results are useful to prevent and control water inrush disasters of coal mine.

Sign in / Sign up

Export Citation Format

Share Document