scholarly journals Numerical Simulation on the Seepage Properties of Soil-Rock Mixture

2018 ◽  
Vol 2018 ◽  
pp. 1-10 ◽  
Author(s):  
Ning Zhao ◽  
Yingchao Wang ◽  
Bo Meng ◽  
Ning Luo
Keyword(s):  
Dynamic Viscosity ◽  
Water Inrush ◽  
Water Velocity ◽  
Water Phase ◽  
Phase 2 ◽  
Initial Water ◽  
Fluent Software ◽  
Soil Skeleton ◽  
Seepage Properties ◽  
Properties Of Soil

To reveal the mechanism of water inrush in a fault tunnel and study the influence of different structures on the seepage process, a filling structure composed of a soil skeleton (fixed particles), a movable particles phase, and a water phase is constructed to simulate the rock mass broken by the fault. Fluent software is used to simulate the migration of the water phase in three different filling structures under different initial water velocities and dynamic viscosities. The variation law of the seepage time with the initial water velocity and dynamic viscosity in the three types of filling structures is obtained. The research shows the following: (1) the looser the filling structure, the greater the influence of gravity on the water phase seepage; the more compact the filling structure, the greater the spread range of the water phase and the more uniform the spread of the water phase. (2) The seepage time decreases with the increase in the initial water velocity. The seepage time and initial water velocity can be fitted by an exponential function. The effect of initial water velocity on seepage time is much greater than that of the structure. (3) The seepage time is related to both the dynamic viscosity and the structure. The seepage time increases with the increase in dynamic viscosity.

scholarly journals Investigation on the Water Flow Evolution in a Filled Fracture under Seepage-Induced Erosion

Water ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 3188
Author(s):  
Jianli Shao ◽  
Qi Zhang ◽  
Xintao Wu ◽  
Yu Lei ◽  
Xunan Wu ◽  
...  
Keyword(s):  
Engineering Geology ◽  
Water Inrush ◽  
Stable Phase ◽  
Roughness Coefficient ◽  
Seepage Velocity ◽  
Linear Change ◽  
Flow Evolution ◽  
Seepage Characteristics ◽  
Seepage Properties ◽  
Safe Mining

Water inrush is a major geological hazard for safe mining and tunnel construction. For the water inrush channel containing mud, sand, and other sediments, it is difficult to predict the change of permeability and water surge, which makes disaster prevention difficult. As a typical water inrush channel, a filled fracture under seepage-induced erosion needs to be focused. In this work, a numerical model for the evolution of flow in a filled fracture under seepage-induced erosion was established, which included the seepage velocity, hydraulic erosion, and permeability of the filling medium. The effects of joint roughness coefficient (JRC) and homogeneity of the filling medium on the seepage evolution are discussed. The results showed that the fracture seepage properties experienced a non-linear change process, and the evolution can be divided into three phases: the slowly varying phase, the rapidly varying phase, and the stable phase. The increase of the JRC hindered the development in flow velocity and erosion. Compared with low homogeneous filling medium, pores in the high homogeneous filling medium were easier to expand and connect, and the seepage characteristics evolved faster. The model established in this study will help to understand the seepage evolution of filled fractures, and can be used to predict the permeability of filled fractures in engineering geology.

Numerical Modeling of Formation of High-Speed Water Slugs

2004 ◽  
Vol 126 (2) ◽  
pp. 206-209 ◽  
Author(s):  
O. Petrenko ◽  
E. S. Geskin ◽  
G. A. Atanov ◽  
A. Semko ◽  
B. Goldenberg
Keyword(s):  
Numerical Modeling ◽  
Finite Difference Method ◽  
High Speed ◽  
Method Of Characteristics ◽  
Computational Procedure ◽  
Water Velocity ◽  
Initial Water ◽  
Explosion Products ◽  
The Finite Difference Method ◽  
Powder Combustion

The objective of this work is to investigate acceleration of a water slug by the powder explosion. The process occurs in a device termed the water cannon, which entails a barrel with an attached nozzle. The explosion products expel the slug from the barrel at an extremely high speed. Due to the acceleration in the nozzle the speed of the slug significantly exceeds that of a bullet driven by the similar explosion. The computational procedure was used to evaluate the pressure, velocity and density fields in the course of slug acceleration in the x-t space. The procedure is based on the finite difference method and the method of characteristics. The initial water velocity and pressure are assumed to be zero. The pressure at water-explosion product interface is determined by the conditions of the powder combustion while the pressure at the water-atmosphere interface is equal to zero. The results of the computations enable us to explain the peculiarities of the operation of the water cannon and to optimize device design.

scholarly journals A Coupled Nonlinear Flow Model for Particle Migration and Seepage Properties of Water Inrush through Broken Rock Mass

Geofluids ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-14
Author(s):  
Wenhao Shi ◽  
Tianhong Yang
Keyword(s):  
Rock Mass ◽  
Small Particle ◽  
High Velocity ◽  
Flow Behavior ◽  
Water Inrush ◽  
Particle Migration ◽  
Nonlinear Flow ◽  
Rock Mass Structure ◽  
Proposed Model ◽  
Seepage Properties

A large number of statistics indicate that broken rock mass always transforms into a flowing channel and leads to water inrush disasters in mining engineering, such as fault, karst, and strongly weathered rock mass. During the process of water inrush, the structure of the broken rock mass is constantly changing due to seepage erosion under high-velocity flow. Therefore, it is of vital importance to quantitatively evaluate the flow behavior of the water inrush related to the seepage erosion in order to prevent or reduce the risks. This study described a coupled nonlinear flow model, which couples the high-velocity seepage, the small particle migration, and the evolution of the broken rock mass structure. The model was verified firstly for simulation of nonlinear flow behavior by comparing with the traditional one. Then, the proposed model was used to simulate the evolution of particle migration and seepage properties of the water inrush through broken rock mass by a numerical case. The simulation results generally agree well with the existing experimental results. The simulations indicate that small particle migration causes the unstable characteristics of the seepage and the heterogeneity properties of the broken rock mass, which lead to the nonlinear flow behavior of the water inrush in both time and space. From a different perspective, it also indicates that the proposed model is capable of simulating the interaction of high-velocity seepage, small particle migration, and evolution of broken rock mass structure in the process of water inrush.

Numerical Simulation of a Helical Pipe Coalescence Device

2012 ◽  
Vol 516-517 ◽  
pp. 1062-1065
Author(s):  
Zhen Wang ◽  
Ming Hu Jiang ◽  
Ping Tao Hou ◽  
Qing Jiao Sheng ◽  
Li Xin Zhao
Keyword(s):  
Numerical Simulation ◽  
Structural Parameters ◽  
Water Phase ◽  
Pipe Diameter ◽  
Gyration Radius ◽  
Oil Droplet ◽  
Inlet Velocity ◽  
Helical Pipe ◽  
Fluent Software ◽  
Operation Parameters

A model of coalescing helical pipe is established through the analysis to the oil phase in continuous water phase inside a helical pipe, by using Fluent software. The influence of structural parameters and operation parameters of helical pipes on oil droplet coalescing effect is verified. Results show that the oil drop coalescing effect increases with the rise of gyration radius and number of turns of helical pipe, and decreases with the rise of the helical pipe diameter and inlet velocity.

scholarly journals Were all trilobites fully marine? Trilobite expansion into brackish water during the early Palaeozoic

2021 ◽  
Vol 288 (1944) ◽  
pp. 20202263
Author(s):  
M. Gabriela Mángano ◽  
Luis A. Buatois ◽  
Beatriz G. Waisfeld ◽  
Diego F. Muñoz ◽  
N. Emilio Vaccari ◽  
...  
Keyword(s):  
Salinity Stress ◽  
Brackish Water ◽  
Phase 1 ◽  
Water Phase ◽  
Marine Environments ◽  
Phase 2 ◽  
Early Palaeozoic ◽  
Body Fossil ◽  
Early Late ◽  
Tolerance To Salinity

Trilobites, key components of early Palaeozoic communities, are considered to have been invariably fully marine. Through the integration of ichnological, palaeobiological, and sedimentological datasets within a sequence-stratigraphical framework, we challenge this assumption. Here, we report uncontroversial trace and body fossil evidence of their presence in brackish-water settings. Our approach allows tracking of some trilobite groups foraying into tide-dominated estuaries. These trilobites were tolerant to salinity stress and able to make use of the ecological advantages offered by marginal-marine environments migrating up-estuary, following salt wedges either reflecting amphidromy or as euryhaline marine wanderers. Our data indicate two attempts of landward exploration via brackish water: phase 1 in which the outer portion of estuaries were colonized by olenids (Furongian–early late Tremadocian) and phase 2 involving exploration of the inner to middle estuarine zones by asaphids (Dapingian–Darriwilian). This study indicates that tolerance to salinity stress arose independently among different trilobite groups.

scholarly journals Seepage Property of Crushed Mudstone Rock in Collapse Column

2020 ◽  
Vol 2020 ◽  
pp. 1-10 ◽  
Author(s):  
Bo-Yang Zhang ◽  
Zhi-Bin Lin
Keyword(s):  
Particle Size ◽  
Water Resource ◽  
Water Inrush ◽  
Underground Water ◽  
Economic Losses ◽  
Karst Collapse ◽  
Hydraulic Pressure ◽  
Water Flow Velocity ◽  
Collapse Column ◽  
Seepage Properties

The karst collapse column composed of crushed rocks and fine argillaceous or clay particles is easy to form the fissure channels between the coal seam working face and the confined limestone aquifer under mining and causes water inrush disasters with the loss of underground water resource, economic losses, and casualties. It is of great necessity to understand the seepage properties of crushed rock in karst collapse column for the prevention of water inrush and the protection of underground water resource. A self-developed seepage test system is used in this paper to conduct laboratory experiments on seepage properties of crushed mudstone specimens. The effects of the particle size distribution, the porosity (specimen height), and the hydraulic pressure on the water flow velocity and the permeability of crushed specimen are analyzed. The results indicate that the permeability of specimen increases with the particle size, porosity, and hydraulic pressure. It can be known from the comparative experiments of progressive hydraulic pressure on one specimen and variable hydraulic pressure on different specimens with constant particle size and porosity that more fine particles leak out from the specimen with repeated application of hydraulic pressure on one specimen. Therefore, the permeability of one specimen is bigger than that of different specimens under the condition of same hydraulic pressure.

scholarly journals Analisis Perancangan Penstock PLTMH di Eremerasa Kabupaten Bantaeng Dengan Menggunakan ANSYS

2019 ◽  
Vol 17 (1) ◽  
pp. 16
Author(s):  
Suryanto Suryanto ◽  
Apollo Apollo ◽  
Muhammad Julham Hamzah ◽  
Titiek Israwati
Keyword(s):  
Fluid Flow ◽  
Fluid Velocity ◽  
Water Velocity ◽  
Hydraulic Efficiency ◽  
Ansys Fluent ◽  
Effective Height ◽  
Fluent Software ◽  
Simulation Results ◽  
Water Turbines ◽  
Design Power

Penstock acts as a distributor of fluid flow between the tank and the turbine. The aims of this study are to determine the characteristics of the pressure and the water velocity and flow pattern that occurs in the penstock and to determine the efficiency of hydraulic optimum turbine with design power 40 kW. Characteristics are analyzed by simulation using Ansys fluent software. The simulation results assist in the design process and design of water turbines penstock accurately and shorten the time. Based on the simulation results in the penstock, the pressure varies on along the penstock and maximum occur on the inlet side (33652 Pa) and then gradually drops along the pipeline and reach the minimum conditions on the outlet side (2651 Pa). Characteristics of the fluid velocity tends to be constant from the inlet side to the outlet side (2,46 m/s), but there are fluctuations in flow velocity in the bend of 10° and 45°. The pattern of the flow of water along the penstock pipe turbulent, especially in connection with angle bends 45° and 10°. Angle turn follow the existing topography. Additionally, it obtained maximum turbine power of 50,617 kW with hydraulic efficiency of 68.93% and the effective height of the turbine is equal to 17,234 m and a discharge of 0,3 m3/s.

scholarly journals Influence of Dodecyltrimethylammonium Halides on Thermotropic Phase Behaviour of Phosphatidylcholine/Cholesterol Bilayers

2000 ◽  
Vol 55 (9-10) ◽  
pp. 753-757 ◽  
Author(s):  
Bożenna Różycka-Roszak ◽  
Hanna Pruchnik
Keyword(s):  
Phase 1 ◽  
Phase Behaviour ◽  
Water Phase ◽  
Lipid Phase ◽  
Dodecyltrimethylammonium Bromide ◽  
Phase 2 ◽  
H Nmr ◽  
Dodecyltrimethylammonium Chloride ◽  
Series Of Experiments ◽  
Mixed Film

Abstract Effects of dodecyltrimethylammonium chloride (DTAC), dodecyltrimethylammonium bromide (DTAB) and dodecyltrimethylammonium iodide (DTAI) on thermotropic phase behaviour of phosphatidylcholine bilayers containing cholesterol as well as on 1H NMR spectra were studied. Two series of experiments were performed. In the first one the surfactants were added to the water phase while in the other directly to the lipid phase (a mixed film from cholesterol, surfactant and phosphatidylcholine was formed). The effects of particular surfactants on the main phase transition temperature, Tm, were more pronounced when added to the lipid phase (2nd method) than to the water phase ( 1st method); the opposite happened when cholesterol was absent (Różycka-Roszak and Pruchnik 2000, Z. Naturforsch. 55c, 240-244). Furthermore, in the case of the first method the transitions were asymmetrical while in the second method nearly symmetrical. It is suggested that surfactant poor and surfactant rich domains are formed when surfactants are added to the water phase.

scholarly journals Methodology of using the Adjoint solver optimization tool during flow in the intercooler filling line to minimize pressure drop

2019 ◽  
Vol 213 ◽  
pp. 02025
Author(s):  
Veronika Horová ◽  
Marian Bojko ◽  
Josef Dobeš
Keyword(s):  
Mathematical Model ◽  
Pressure Drop ◽  
Dynamic Viscosity ◽  
Second Phase ◽  
Pressure Gradients ◽  
Ansys Fluent ◽  
Fluent Software ◽  
The Mathematical Model ◽  
Convergent Solution ◽  
Filling Line

The paper deals with numerical modelling of the flow in the intercooler filling line by Adjoint solver to minimize pressure loss. The ANSYS Fluent software was used for the calculations. The basic flow calculation was performed in the first phase. Then the mathematical model with Adjoint solver optimization tool was defined. The numerical calculation was unstable and did not lead to a convergent solution, because of creation of vortexes. The mathematical model was simplified in the second phase. To suppress instabilities and vortices a dynamic viscosity of coolant was adjusted. The pressure gradients between inlet and outlet for unmodified geometry and for modified geometry were evaluated. The final evaluations of pressure drop changes were implemented for modified geometry with original dynamic viscosity of the coolant.

scholarly journals Impact of Cooling on Water and Salt Migration of High-Chlorine Saline Soils

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Runze Tian ◽  
Yu Zhang ◽  
Anhua Xu ◽  
Xuemei Li ◽  
Yunlong Hou ◽  
...  
Keyword(s):  
Phase Transition ◽  
Water Content ◽  
Saline Soil ◽  
Water Phase ◽  
Saline Soils ◽  
Initial Water Content ◽  
Cooling Process ◽  
Crystallization Water ◽  
Initial Water ◽  
Salt Migration

Secondary salinization is a common problem in saline soil projects. In order to grasp the mechanism of water and salt migration of high-chlorine saline soil during the cooling process, the saline soils along the Qarhan-Golmud Highway in the Qinghai-Tibet Plateau were selected as test samples. Firstly, the basic physical parameter test and the soluble salt chemical experiment were carried out and obtained liquid and plastic limits, dry density, etc. Secondly, freezing temperature experiments and water-salt migration experiments under one-way cooling conditions were conducted according to the actual environmental conditions, and after the temperature gradient line of the soil sample was stable, water content and labile salt chemistry experiments were conducted to obtain the distribution of water and salt contents of soil samples. Finally, the effect of crystallization-water phase transition on water and salt migration and the effect of chloride salt on the temperature of crystallization-water phase transition were considered, and a mathematical model applicable to the water and salt migration of highly chlorinated saline soils under the effect of unidirectional cooling was established and solved with COMSOL Multiphysics software, and the correctness of the model was verified by comparing the simulation results with the experimental results. The study found that (1) during the one-way cooling process, both water and salt showed a tendency to migrate to the cold end. The MC (saline soil with medium chlorine content) with an initial water content of 16.9% and Cl− content of 3.373% was measured to reach a 17.6% water content and 3.76% Cl− content at the cold (top) end after the experiment. The HC (saline soil with high chlorine content) with an initial water content of 6.6% and Cl− content of 17.928% was measured to reach a 6.83% water content and 18.8% Cl− content after the experiment and (2) after the one-way cooling experiment of the MC, the water content at a distance of 1–2 cm from the cold end has abrupt changes, which may be caused by a small amount of crystallization—water phase transition at this location. At the same time, according to the temperature change graph during the cooling process, the phase change temperature was set to −9°C in the numerical simulation process to match the experimental results.

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