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.

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.

scholarly journals Two-phase fluid flow in geometric packing

2015 ◽  
Vol 373 (2056) ◽  
pp. 20150111 ◽  
Author(s):  
Aureliano Sancho S. Paiva ◽  
Rafael S. Oliveira ◽  
Roberto F. S. Andrade
Keyword(s):  
Viscous Fluid ◽  
Volume Fraction ◽  
Equations Of Motion ◽  
Two Phase ◽  
Ansys Fluent ◽  
Injection Speed ◽  
Complex Dependence ◽  
Complete Set ◽  
High Viscous Fluid ◽  
Phase Fluid

We investigate how a plug of obstacles inside a two-dimensional channel affects the drainage of high viscous fluid (oil) when the channel is invaded by a less viscous fluid (water). The plug consists of an Apollonian packing with, at most, 17 circles of different sizes, which is intended to model an inhomogeneous porous region. The work aims to quantify the amount of retained oil in the region where the flow is influenced by the packing. The investigation, carried out with the help of the computational fluid dynamics package ANSYS-FLUENT , is based on the integration of the complete set of equations of motion. The study considers the effect of both the injection speed and the number and size of obstacles, which directly affects the porosity of the system. The results indicate a complex dependence in the fraction of retained oil on the velocity and geometric parameters. The regions where the oil remains trapped is very sensitive to the number of circles and their size, which influence in different ways the porosity of the system. Nevertheless, at low values of Reynolds and capillary numbers Re <4 and n c ≃10 −5 , the overall expected result that the volume fraction of oil retained decreases with increasing porosity is recovered. A direct relationship between the injection speed and the fraction of oil is also obtained.

scholarly journals Computational fluid simulation of non-Newtonian two-phase fluid flow through a channel with a cavity

2020 ◽  
Vol 24 (2 Part B) ◽  
pp. 1045-1054 ◽  
Author(s):  
Mehdi Ahmadi ◽  
Farsani Khosravi
Keyword(s):  
Reynolds Number ◽  
Fluid Flow ◽  
Newtonian Fluid ◽  
Volume Fraction ◽  
Staggered Grid ◽  
Mixed Solution ◽  
Two Phase ◽  
Flow Through ◽  
Velocity Pressure ◽  
Phase Fluid

In this paper, the numerical solution of non-Newtonian two-phase fluid-flow through a channel with a cavity was studied. Carreau-Yasuda non-Newtonian model which represents well the dependence of stress on shear rate was used and the effect of n index of the model and the effect of input Reynolds on the attribution of flow were considered. Governing equations were discretized using the finite volume method on staggered grid and the form of allocating flow parameters on staggered grid is based on marker and cell method. The QUICK scheme is employed for the convection terms in the momentum equations, also the convection term is discretized by using the hybrid upwind-central scheme. In order to increase the accuracy of making discrete, second order Van Leer accuracy method was used. For mixed solution of velocity-pressure field SIMPLEC algorithm was used and for pressure correction equation iteratively line-by-line TDMA solution procedure and the strongly implicit procedure was used. As the results show, by increasing Reynolds number, the time of sweeping the non-Newtonian fluid inside the cavity decreases, the velocity of Newtonian fluid increases and the pressure decreases. In the second section, by increasing n index, the velocity increases and the volume fraction of non-Newtonian fluid after cavity increases and by increasing velocity, the pressure decreases. Also changes in the velocity, pressure and volume fraction of fluids inside the channel and cavity are more sensible to changing the Reynolds number instead of changing n index.

The Effect of Shape Factor on the Magnetic Targeting in the Permeable Microvessel With Two-Phase Casson Fluid Model

2011 ◽  
Vol 2 (4) ◽  
Author(s):  
Sachin Shaw ◽  
P. V. S. N. Murthy
Keyword(s):  
Magnetic Field ◽  
Volume Fraction ◽  
Fluid Model ◽  
Casson Fluid ◽  
Magnetic Drug Targeting ◽  
Magnetic Targeting ◽  
Two Phase ◽  
Coupled Equations ◽  
Casson Fluid Model ◽  
Phase Fluid

The present investigation deals with magnetic drug targeting in a microvessel of radius 5 μm using two-phase fluid model. The microvessel is divided into the endothelial glycocalyx layer wherein the blood obeys Newtonian character and a core region wherein the blood obeys the non-Newtonian Casson fluid character. The carrier particles, bound with nanoparticles and drug molecules, are injected into the vascular system upstream from the malignant tissue and are captured at the tumor site using a local applied magnetic field near the tumor position. Brinkman model is used to characterize the permeable nature of the inner wall of the microvessel. The expressions for the fluidic force for the carrier particle traversing in the two-phase fluid in the microvessel and the magnetic force due to the external magnetic field are obtained. Several factors that influence the magnetic targeting of the carrier particles in the microvasculature, such as the size and shape of the carrier particle, the volume fraction of embedded magnetic nanoparticles, and the distance of separation of the magnet from the axis of the microvessel, are considered in the present problem. The system of coupled equations is solved to obtain the trajectories of the carrier particle in the noninvasive case.

A Volume Fraction Based Two-Phase Constitutive Model for Blood

2008 ◽  
Author(s):  
Rui Zhao ◽  
Mehrdad Massoudi ◽  
Samuel J. Hund ◽  
James F. Antaki
Keyword(s):  
Mathematical Model ◽  
Constitutive Model ◽  
Volume Fraction ◽  
Research Project ◽  
Two Phase ◽  
Cardiovascular Devices ◽  
Micro Scale ◽  
Model Based ◽  
Broad Understanding ◽  
Blood Trauma

Mechanically-induced blood trauma such as hemolysis and thrombosis often occurs at microscopic channels, steps and crevices within cardiovascular devices. A predictive mathematical model based on a broad understanding of hemodynamics at micro scale is needed to mitigate these effects, and is the motivation of this research project.

scholarly journals A Coupled Model of Two-Phase Fluid Flow and Heat Transfer to Transient Temperature Distribution and Seepage Characteristics for Water-Flooding Production Well with Multiple Pay Zones

Energies ◽  
2019 ◽  
Vol 12 (10) ◽  
pp. 1854
Author(s):  
Guoshu Huang ◽  
Huolin Ma ◽  
Xiangyun Hu ◽  
Jianchao Cai ◽  
Jiabin Li ◽  
...  
Keyword(s):  
Water Saturation ◽  
Coupled Model ◽  
Water Flooding ◽  
Transient Temperature ◽  
Production Well ◽  
Seepage Velocity ◽  
Two Phase ◽  
Flow And Heat Transfer ◽  
Seepage Characteristics ◽  
Phase Fluid

Temperature is one of the most prominent factors affecting production operations, predicting the accurate wellbore-formation temperature in a water-flooding production well is of great importance for multiple applications. In this paper, an improved coupled model of oil–water two-phase fluid flow and heat transfer was developed to investigate the transient temperature behavior for a producing well with multiple pay zones. Firstly, a novel method was derived to simulate the water saturation and the water breakthrough time (WBT) for tubing, which are key monitoring parameters in the process of water flooding. Then, we incorporated water saturation and an equation set for immiscible displacement to calculate the seepage velocity and the pressure of the two-phase fluid in the pay zones. Next, the upward seepage velocity of the tubing fluid change with depth was focused on, and the proper coupled initial and boundary conditions are presented at the interfaces, therewith the implicit finite difference method was used to compute the transient temperature with the input of the seepage characteristics for the reservoirs. Meanwhile, the validity of the proposed model has been verified by the typical model. Finally, a sensitivity analysis delineated that the production rate and the production time had a significant impact on the tubing fluid temperature. The overburden was hotter with a lower volumetric heat capacity or a higher thermal conductivity. In addition, the sensitivity of the porosity and the irreducible water saturation to formation temperature was significantly different before and after the WBT. The coupled model presented herein helps to advance the transient seepage characteristics analysis of pay zones, the precise temperature prediction is very useful for reservoir characterization and production analysis purposes and provides insight for designing the exploitation scheme in deep reservoirs and geothermal resources.

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.

Numerical Investigation of Sediment-Laden Flow in a High-Head Francis Turbine Runner

2013 ◽  
Vol 860-863 ◽  
pp. 1542-1546
Author(s):  
Hong Ming Zhang ◽  
Li Xiang Zhang
Keyword(s):  
Erosion Rate ◽  
Volume Fraction ◽  
Three Dimensional ◽  
Suction Side ◽  
Francis Turbine ◽  
Two Phase ◽  
Flow Equations ◽  
Maximum Value ◽  
Sand Erosion ◽  
Turbine Runner

The 3-D turbulent particulate-liquid two-phase flow equations are employed in this study. The computing domain is discretized with a full three-dimensional mesh system of unstructured tetrahedral shapes. The finite volume method is used to solve the governing equations and the pressure-velocity coupling is handled via a Pressure Implicit with Splitting of Operators (PISO) procedure. Simulation results have shown that the sand erosion rate on pressure side is more than on the suction side of the blade. The maximum value of sand volume fraction and the maximum value of sand erosion rate are at same location.

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