scholarly journals Effect of Seepage Velocity on Formation of Shaft Frozen Wall in Loose Aquifer

2018 ◽  
Vol 2018 ◽  
pp. 1-11 ◽  
Author(s):  
Jian Lin ◽  
Hua Cheng ◽  
Hai-bing Cai ◽  
Bin Tang ◽  
Guang-yong Cao
Keyword(s):  
Numerical Simulation ◽  
Optimization Design ◽  
Coupling Effect ◽  
Measurement Data ◽  
Freezing Process ◽  
Seepage Velocity ◽  
Finite Element Software ◽  
Frozen Wall ◽  
Simulation Results ◽  
The Impact

This paper addresses the difficult closure of a frozen wall in a coal mine shaft due to excessive seepage velocity in an aquifer when the aquifer is penetrated via the artificial freezing method. Based on hydrothermal coupling theory and considering the effect of decreased absolute porosity on seepage during the freezing process, a mathematical model of hydrothermal full-parameter coupling with a phase change is created. A shaft is used as a prototype, and COMSOL multiphysics finite element software is employed to perform a numerical simulation of the shaft freezing process at various stratum seepage velocities. The numerical simulation results are verified via a comparison with field measurement data. Based on the numerical simulation results, the impact of various underground water seepage velocities on the artificial frozen wall formation process with the seepage-temperature field coupling effect is analysed. Based on the analysis results, the recommended principles of the optimization design for a freezing plan are described as follows: first, the downstream area is closed to enable the water insulation effect, and second, the closure of the upstream area is expedited to reduce the total closure time of a frozen wall.

Solid-Gas Coupling Model and Numerical Simulation of Coal Containing Gas Based on Comsol Multiphysic

2012 ◽  
Vol 616-618 ◽  
pp. 515-520
Author(s):  
Sheng Zhou Li ◽  
Chang Bao Jiang ◽  
Jun Wei Yao ◽  
Ming Hui Li
Keyword(s):  
Numerical Simulation ◽  
Failure Modes ◽  
Coupling Effect ◽  
Coupling Model ◽  
Klinkenberg Effect ◽  
Deformation And Failure ◽  
Finite Element Software ◽  
Porosity And Permeability ◽  
Simulation Results ◽  
Seepage Law

Solid-gas coupling effect of coal containing gas is studied in order to understand the gas percolation mechanism in coal and rock. On the premise of that porosity and permeability of coal and rock are in dynamic changes and Klinkenberg effect, then seepage mechanics and elastic-plastic mechanics are considered together to established solid-gas coupling model of coal containing gas. With the given fixed solution conditions and parameters, the simulation results of mathematical model is found by the Comsol Multiphysic finite element software. Simulation results are consistent with the stress-strain law, deformation and failure modes of specimen in the experiment. Seepage law obtained in numerical simulation has same trends with experimental data. The elastoplastic solid-gas coupling model of coal containing gas can effectively describe the mechanical percolation characteristics of coal containing gas.

Investigation on penetration model of shaped charge jet in water

2016 ◽  
Vol 30 (02) ◽  
pp. 1550268 ◽  
Author(s):  
Jinwei Shi ◽  
Xingbai Luo ◽  
Jinming Li ◽  
Jianwei Jiang
Keyword(s):  
Numerical Simulation ◽  
Theoretical Model ◽  
Model Simulation ◽  
Theoretical Models ◽  
Theoretical Research ◽  
Water Medium ◽  
Simulation Results ◽  
Jet Penetration ◽  
The Impact ◽  
Penetration Velocity

To analyze the process of jet penetration in water medium quantitatively, the properties of jet penetration spaced target with water interlayer were studied through test and numerical simulation. Two theoretical models of jet penetration in water were proposed. The theoretical model 1 was established considering the impact of the shock wave, combined with the shock equation Rankine–Hugoniot and the virtual origin calculation method. The theoretical model 2 was obtained by fitting theoretical analysis and numerical simulation results. The effectiveness and universality of the two theoretical models were compared through the numerical simulation results. Both the models can reflect the relationship between the penetration velocity and the penetration distance in water well, and both the deviation and stability of theoretical model 1 are better than 2, the lower penetration velocity, and the larger deviation of the theoretical model 2. Therefore, the theoretical model 1 can reflect the properties of jet penetration in water effectively, and provide the reference of model simulation and theoretical research.

Numerical Modeling of Multi-Frequency Complex Dielectric Permittivity Dispersion of Sedimentary Rocks

Geophysics ◽  
2021 ◽  
pp. 1-69
Author(s):  
Artur Posenato Garcia ◽  
Zoya Heidari
Keyword(s):  
Numerical Simulation ◽  
Dielectric Permittivity ◽  
Numerical Simulations ◽  
Dielectric Response ◽  
Water Saturation ◽  
Pore Scale ◽  
Simulation Results ◽  
Wet Rocks ◽  
Permittivity Measurements ◽  
The Impact

The dielectric response of rocks results from electric double layer (EDL), Maxwell-Wagner (MW), and dipolar polarizations. The EDL polarization is a function of solid-fluid interfaces, pore water, and pore geometry. MW and dipolar polarizations are functions of charge accumulation at the interface between materials with contrasting impedances and the volumetric concentration of its constituents, respectively. However, conventional interpretation of dielectric measurements only accounts for volumetric concentrations of rock components and their permittivities, not interfacial properties such as wettability. Numerical simulations of dielectric response of rocks provides an ideal framework to quantify the impact of wettability and water saturation ( Sw) on electric polarization mechanisms. Therefore, in this paper we introduce a numerical simulation method to compute pore-scale dielectric dispersion effects in the interval from 100 Hz to 1 GHz including impacts of pore structure, Sw, and wettability on permittivity measurements. We solve the quasi-electrostatic Maxwell's equations in three-dimensional (3D) pore-scale rock images in the frequency domain using the finite volume method. Then, we verify simulation results for a spherical material by comparing with the corresponding analytical solution. Additionally, we introduce a technique to incorporate α-polarization to the simulation and we verify it by comparing pore-scale simulation results to experimental measurements on a Berea sandstone sample. Finally, we quantify the impact of Sw and wettability on broadband dielectric permittivity measurements through pore-scale numerical simulations. The numerical simulation results show that mixed-wet rocks are more sensitive than water-wet rocks to changes in Sw at sub-MHz frequencies. Furthermore, permittivity and conductivity of mixed-wet rocks have weaker and stronger dispersive behaviors, respectively, when compared to water-wet rocks. Finally, numerical simulations indicate that conductivity of mixed-wet rocks can vary by three orders of magnitude from 100 Hz to 1 GHz. Therefore, Archie’s equation calibrated at the wrong frequency could lead to water saturation errors of 73%.

Influence of Engine Cabin Simplification on Aerodynamic Characteristics of Car

2014 ◽  
Vol 1042 ◽  
pp. 188-193 ◽  
Author(s):  
Xing Jun Hu ◽  
Jing Chang
Keyword(s):  
Numerical Simulation ◽  
Aerodynamic Drag ◽  
Aerodynamic Characteristics ◽  
Thin Plates ◽  
Average Thickness ◽  
Two Dimensional ◽  
Engine Cooling ◽  
Aerodynamic Drag Coefficient ◽  
Simulation Results ◽  
The Impact

In order to analyze the impact of engine cabin parts on aerodynamic characteristics, the related parts are divided into three categories except the engine cooling components: front thin plates (average thickness of 2mm), bottom-suspension and interior panels. The aerodynamic drag coefficient (Cd) were obtained upon the combination schemes consisting of the three types of parts by numerical simulation. Results show that Cd by simulation is closer to the test value gained by the wind tunnel experiment when front thin plates were simplified to the two-dimensional interface with zero thickness. The error is only 5.23%. Meanwhile this scheme reduces grid numbers, thus decreasing the calculating time. As the front thin plates can guide the flow, there is no difference on the Cd values gained from the model with or without bottom-suspension or interior panels when the engine cabin contains the front thin plates; while only both bottom-suspension and interior panels are removed, the Cd value can be reduced when the cabin doesn’t contain the front thin plates.

Numerical Simulation and Analysis on the Impact Effect of Cylindrical Projectile Impacting Shelled Explosive

2013 ◽  
Vol 710 ◽  
pp. 320-324
Author(s):  
Ying Zi Jiang ◽  
Wei Li Wang ◽  
Xue Feng Huang ◽  
Lei Fu ◽  
Zhuang Qing Fan
Keyword(s):  
Numerical Simulation ◽  
Energy Criterion ◽  
Critical Energy ◽  
Simplified Model ◽  
Initiation Point ◽  
4340 Steel ◽  
Simulation Results ◽  
The Impact ◽  
Explosive Detonation ◽  
Critical Initiation

The numerical simulation of shelled Comp.B explosive was studied following the Lee-Tarver ignition and growth model when it was impacted respectively by 4340 Steel, OFHC and 93#W projectile with the same mass; the influences on explosive detonation of the initiation process, the material of projectile and the L/D ratio of projectile were analyzed; the critical initiation speeds of the projectiles of three different materials with different L/D ratio were gained. In order to verify the simulation results, the questions were calculated by the theoretical simplified model, the results of the theoretical calculation and the numerical simulation accorded well based on critical energy criterion. The results show that the capability of igniting explosive, the first is 93#W, the second is OFHC, the last is 4340 Steel; The initiation point were not on the interface of shell and explosive, and the faster of the impacting velocity, the initiation point closer the interface; the bigger of the L/D ratio of projectile, the higher of the critical initiation speed.

scholarly journals Mechatronic Device for Locomotor Training

2016 ◽  
Vol 10 (4) ◽  
pp. 310-315 ◽  
Author(s):  
Sławomir Duda ◽  
Damian Gąsiorek ◽  
Grzegorz Gembalczyk ◽  
Sławomir Kciuk ◽  
Arkadiusz Mężyk
Keyword(s):  
Experimental Data ◽  
Numerical Simulation ◽  
Measurement Data ◽  
Healthy Person ◽  
Control Algorithms ◽  
Design Team ◽  
Locomotor Training ◽  
Interdisciplinary Design ◽  
Machine Control ◽  
Simulation Results

Abstract This paper presents a novel mechatronic device to support a gait reeducation process. The conceptual works were done by the interdisciplinary design team. This collaboration allowed to perform a device that would connect the current findings in the fields of biomechanics and mechatronics. In the first part of the article shown a construction of the device which is based on the structure of an overhead travelling crane. The rest of the article contains the issues related to machine control system. In the prototype, the control of drive system is conducted by means of two RT-DAC4/PCI real time cards connected with a signal conditioning interface. Authors present the developed control algorithms and optimization process of the controller settings values. The summary contains a comparison of some numerical simulation results and experimental data from the sensors mounted on the device. The measurement data were obtained during the gait of a healthy person.

Numerical Simulation of the Kinetic Energy Projectile Oblique Penetration into the Concrete

2014 ◽  
Vol 989-994 ◽  
pp. 982-985
Author(s):  
Jun Chen ◽  
Xiao Jun Ye
Keyword(s):  
Numerical Simulation ◽  
Finite Element ◽  
Kinetic Energy ◽  
Three Dimensional ◽  
Test Results ◽  
Destruction Process ◽  
3D Finite Element ◽  
Finite Element Software ◽  
Simulation Results ◽  
Target Characteristics

ANSYS-LS/DYNA 3D finite element software projectile penetrating concrete target three-dimensional numerical simulation , has been the target characteristics and destroy ballistic missile trajectory , velocity and acceleration and analyze penetration and the time between relationship , compared with the test results , the phenomenon is consistent with the simulation results. The results show that : the destruction process finite element software can better demonstrate concrete tests revealed the phenomenon can not be observed , estimated penetration depth and direction of the oblique penetration missile deflection .

scholarly journals Experimental Research and Numerical Simulation on Grouting Quality of Shield Tunnel Based on Impact Echo Method

2016 ◽  
Vol 2016 ◽  
pp. 1-10
Author(s):  
Fei Yao ◽  
Guangyu Chen ◽  
Jianhong Su
Keyword(s):  
Numerical Simulation ◽  
Finite Element ◽  
Working Conditions ◽  
Acoustic Impedance ◽  
Shield Tunnel ◽  
Test Results ◽  
Impact Echo ◽  
Simulation Results ◽  
The Impact ◽  
Impact Echo Method

To identify shield grouting quality based on impact echo method, an impact echo test of segment-grouting (SG) test piece was carried out to explore effect of acoustic impedance of grouting layers and grouting defects on impact echo law. A finite element numerical simulation on the impact echo process was implemented. Test results and simulation results were compared. Results demonstrated that, under some working conditions, finite element simulation results and test results both agree with theoretical values. The acoustic impedance ratio of SG material influenced the echo characteristics significantly. But thickness frequency could not be detected under some working conditions because the reflected energy is weak. Frequency feature under grouting defects was more complicated than that under no grouting defects.

The Optimization of Vibration Induced by a V6 Engine Cooling Module

2011 ◽  
Author(s):  
Ji Yang ◽  
Zhiyong Hao ◽  
Ruwei Ge ◽  
Liansheng Wang ◽  
Kang Zheng
Keyword(s):  
Numerical Simulation ◽  
Numerical Model ◽  
Automotive Industry ◽  
Optimization Design ◽  
Working Condition ◽  
Steering Wheel ◽  
Engine Cooling ◽  
Simulation Results ◽  
Cooling Module ◽  
Specific Working

The engine cooling module consists of condenser, radiator and fan (CRFM), which has long been recognized as a main source of sound and vibration in the automotive industry. As the engine becomes increasingly compact and powerful, customers gradually have higher expectations for automobile NVH performance than ever before. Thus the reduction of noise and vibration induced by CRFM becomes critical, which can greatly influence overall NVH performance. Combined with experimental and numerical methods, this paper focuses on the identification and optimization of steering wheel (SW) vibration induced by CRFM for a vehicle with V6 engine while engine idling. The numerical model established in this paper, based on Matlab and taking chassis vibration into account, can predict and optimize the vibration of CRFM under specific working condition with the help of energy decoupling and Newmark-Beta methodology. The optimization design of CRFM mainly involves the stiffness, position and angle of isolators. The numerical simulation results are validated experimentally, which can help further design of CRFM.

Research on the Numerical Simulation of Hot Stamping for High Strength Steel

2014 ◽  
Vol 898 ◽  
pp. 136-139
Author(s):  
Chang Feng Men ◽  
Wen Wen Du ◽  
Cui Hong Han
Keyword(s):  
Numerical Simulation ◽  
Finite Element ◽  
High Strength Steel ◽  
Hot Stamping ◽  
High Strength ◽  
Nonlinear Finite Element ◽  
Weight Percentage ◽  
Finite Element Software ◽  
Simulation Results ◽  
Die Temperature

In order to research on the hot stamping property of high strength steel, the stamping forming of USIBOR1500P is simulated by the nonlinear finite element software Dynaform and Ansys/ls-dyna. The initial data simulated on USIBOR1500P is obtained by the hot tensile test. The simulation results show that the martensite weight percentage and Vickers hardness are in inverse proportion to stamping speed and initial die temperature.

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