检索结果-内蒙古大学图书馆

Development and experimental validation of a computational fluid dynamics-discrete element method sand production model

引用

JOURNAL OF NATURAL GAS SCIENCE AND ENGINEERING 2020年 73卷

作者： Song, Yuqi Ranjith, P. G. Wu, Bailin Monash Univ Dept Civil Engn Deep Earth Energy Lab Melbourne Vic 3800 Australia CSIRO Energy Oil Gas & Fuels Res Program Melbourne Vic 3168 Australia

Sand production is a dynamic process that occurs during the production of oil or natural gas, costing the petroleum industry billions of dollars per year to control. The main aim of this research is to develop a numerical model combining the discrete element method with computational fluid dynamics and the using particle flow code to simulate the sand production process, so as to obtain a deeper insight into its mechanisms. The numerical model was validated using sand production data from a specially designed sand production cell. The effects of various variables affecting the sand production process including fluid pressure, sand particle size distribution, and fluid type were investigated. Changing the random number will not influence the macroscopic properties of the sample but affect the microstructure. Selecting the same random number is necessary in each simulation if one wants to keep both the macro and micro properties of samples the same. Running one numerical model with different random numbers can eliminate the haphazard of test. Two main failure modes resulted in sand production: the collapse of thin inner layers of stable sand arches and the thorough collapse of the sand body. When the drawdown pressure was lower than the critical drawdown pressure, the collapse of thin inner layers of stable sand arches prevailed as a failure mode. An unfavourable increase in sand production by thorough collapse of the sand body took place when the drawdown pressure was greater than the critical drawdown pressure. Therefore, determination of the critical drawdown pressure is very important to prevent catastrophic sand production. The closer the drawdown pressure and critical drawdown pressure are, the more difficult it is to form a stable sand arch. The formation of a sand arch was random and haphazard. The proposed numerical model is a promising method for studying the sand production mechanisms.

关键词： Computational fluid dynamics Discrete element method Oil and gas reservoirs particle flow code Critical drawdown pressure Sand production

来源：评论

学校读者我要写书评

暂无评论

A 3D grain-based creep model (3D-GBCM) for simulating long-term mechanical characteristic of rock salt

引用

JOURNAL OF PETROLEUM SCIENCE AND ENGINEERING 2020年第0期185卷 106672-000页

作者： Li, Huan Yang, Chunhe Ma, Hongling Shi, Xilin Zhang, Haina Dong, Zhikai Chinese Acad Sci Inst Rock & Soil Mech State Key Lab Geomech & Geotech Engn Wuhan 430071 Peoples R China Univ Chinese Acad Sci Beijing 100049 Peoples R China Struct Hlth Monitoring & Control Inst Shijiazhuang 050043 Hebei Peoples R China Key Lab Hlth Monitoring & Control Large Struct Shijiazhuang 050043 Hebei Peoples R China

A 3D micro-creep model based on the grain-based structure and the framework of the particle flow code (PFC) approach is proposed. Simultaneously, a Voronoi polyhedral technique is employed to approximatively construct the grain structure of the real rock salt. Based on literature research, an exponential attenuation mode controlled by the temperature and stress-level is assumed to characterize variation behavior of the parallel bond diameter (PBD) with time. This model is then configured to simulate the time-dependent deformation responses associated with the damage features of rock salt. The validity and applicability of this 3D micro-creep model are verified through comparing the steady-state creep rate, multi-steps creep responses, and microcracking modes obtained in lab tests. This work could provide a promising alternative to study the micro-creep damage mechanism of rock salt.

关键词： Rock salt Creep damage particle flow code Exponential function model

来源：评论

学校读者我要写书评

暂无评论

Numerical simulation of permeability evolution in granite after thermal treatment

引用

COMPUTERS AND GEOTECHNICS 2020年 126卷 103705-103705页

作者： Tian, Wen-Ling Yang, Sheng-Qi Wang, Jian-Guo Zeng, Wei China Univ Min & Technol State Key Lab Geomech & Deep Underground Engn Xuzhou 221116 Jiangsu Peoples R China Foshan Univ Sch Transportat & Civil Engn & Architecture Foshan 528000 Peoples R China

The evolution of the permeability of granite at high temperatures has a significant effect on geothermal exploitation. In this study, the fluid-solid coupling algorithm is improved based on the different intra-granular, inter-granular and crack seepage characteristics of granite, and the permeability characteristics of thermally treated granite specimens are simulated under different confining pressures. The results show that the permeability of granite non-linearly decreases with confining pressure in a concave type and its variation with temperature is similar to the experimental results. When T <= 300 degrees C, temperature has a slight effect on the variation of permeability. Because the temperature has a slight effect on the distribution characteristics of the flow rate and pore pressure, the flow rate mainly dependent on the inter-granular contact, which is parallel to the gradient of pore pressure. However, when T >= 450 degrees C, the number of thermally induced cracks increases and forms a coalesced channel;thus, the permeability increases with temperature. The temperature has a significant effect on the distribution characteristics of the flow rate and pore pressure. Confining pressure can decrease the permeability, whereas it has a slight effect on the distribution of flow rate and pore pressure in the specimen.

关键词： Granite Thermal treatment particle flow code Seepage micro-characteristic Permeability

来源：评论

学校读者我要写书评

暂无评论

Investigating Earth Reaction to Pull-Out Process of Frictional Rock Bolts Using Distinct Element Method

引用

Open Journal of Geology 2020年第8期10卷 851-862页

作者： Mohammad Sadegh Ayyoobi Arash Refahi Mining Department Faculty of Engineering University of Zanjan Zanjan Iran

The reaction of earth to pull-out process of frictional rock bolts was here modeled by the distinct element method (DEM). Ten frictional bolts were prepared;the expanding shells of five bolts included convex edges and the others had the shells with concave bits. The strength of bolts was measured by applying a standard pull-out test;the results confirmed that the strength of shells with convex edges was remarkably more than the strength of other shells. Furthermore, a two-dimensional DEM model of the test was developed by a particle flow code;the obtained results showed that the reaction of rock particles to the contacts occurring between the convex edges and earth was considerably more than those of the concave bits. In the other words, the convex edges transferred the pull-out force into a large area of the surrounded rock, causing these bolts to have the highest resistance against earth movements.

关键词： Frictional Rock Bolt Pull-Out Test Distinct Element Method particle flow code

来源：评论

学校读者我要写书评

暂无评论

Numerical Analysis of Negative Skin Friction for Pile under Surface Loading by particle flow code

引用

2nd International Conference on Civil Engineering, Architecture and Building Materials (CEABM 2012)

作者： Zhou Feng-xi Lai Yuan-ming Lanzhou Univ Sch Civil Engn Lanzhou 730000 Gansu Peoples R China Chinese Acad Sci Cold & Arid Regions Environm & Engn Res Inst Lanzhou 730000 Peoples R China

ISBN: (纸本)9783037854211

Numerical simulations of soil-pile interaction under surface loading are performed by particle flow code in two dimensions. Considering an end-bearing pile subjected to flexible distribution load, the variety of negative skin friction is studied. Numerical results show that negative skin friction is variation with the increasing of surface loading, and the negative skin friction is decrease when the value is up to ultimate skin friction.

关键词： particle flow code negative skin friction surface loading pile

来源：评论

学校读者我要写书评

暂无评论

Numerical Simulation on Combined Deformation of Tip-Loaded Cantilever Beam with particle flow code

Numerical Simulation on Combined Deformation of Tip-Loaded C...

引用

International Conference on Applied Materials and Electronics Engineering (AMEE 2012)

作者： Xiong, Yibo Wang, Chunming Peng, Lu NW Inst Nucl Technol Xian 710024 Peoples R China

ISBN: (纸本)9783037852880

In order to calculate the combined deformations of an Euler-Bernoulli cantilever beam subjected to bending moment, twisting moment, transverse load and axial load, particle flow code in 3 dimensions (PFC3D) is used with parallel bonds model. The computed deformations, including transverse deflections, rotations about axis, maximum normal and shear stresses, were compared with the analytical beam-theory solution in terms of axial tension, axial compression and none axial load, respectively. Between computed results and analytical beam-theory solution, the error bands are greater than 99.7% at the beam tip, while the error of the transverse deflection of the whole beam is less than 0.6%. So, the PFC3D is able to precisely simulate the combined deformation of cantilever beam, and this work has special reference to engineering calculations and designs when PFC is applied to model the mechanical behaviors of continuum materials.

关键词： Computational mechanics Cantilever beam Combined deformation particle flow code

来源：评论

学校读者我要写书评

暂无评论

Dynamic structural evolution of overlying strata during shallow coal seam longwall mining

引用

INTERNATIONAL JOURNAL OF ROCK MECHANICS AND MINING SCIENCES 2018年 103卷 20-32页

作者： Wang, Chenlong Zhang, Changsuo Zhao, Xiaodong Liao, Lin Zhang, Shengli Taiyuan Univ Technol Coll Min Engn Taiyuan 030024 Shanxi Peoples R China Dalian Univ China Japan Res Ctr Geoenvironm Sci Dalian 116000 Liaoning Peoples R China Taiyuan Univ Technol Yingze West St 79 Taiyuan 030024 Shanxi Peoples R China

Wang et al discuss the typical characteristics of the coal seams include shallow burial depths, thin bedrocks, and thick unconsolidated quaternary layers. It has also been observed from practice that roof step-form subsidence and chock closure failure disasters often occur during the weighting periods. If the mining activities induces severe roof step-form subsidence, coalescence of open cracks along the palisades may occur, with the consequent formation of penetrating passageways through which water and sand may rush in, resulting in a water and sand inrush disaster on the working face. Coal mine roof disasters constitute serious safety threats in mining practice. Incomplete statistics show that 12 support failure incidents have occurred since 2007 in the Shendong shallow coalfield longwall mining area.

关键词： particle flow code Shallow coal seam Longwall mining Roof structure evolution Roof step-form subsidence

来源：评论

学校读者我要写书评

暂无评论

Numerical investigation of the direct tensile behaviour of laminated and transversely isotropic rocks containing incipient bedding planes with different strengths

引用

COMPUTERS AND GEOTECHNICS 2018年第Dec.期104卷 373-388页

作者： Shang, J. Duan, K. Gui, Y. Handley, K. Zhao, Z. Nanyang Technol Univ Sch Civil & Environm Engn Singapore Singapore Newcastle Univ Sch Engn Newcastle Upon Tyne Tyne & Wear England Univ Leeds Sch Earth & Environm Leeds W Yorkshire England

The anisotropic direct tensile behaviour of laminated and transversely isotropic Midgley Grit sandstone (MGS) was investigated in this paper using a particle-based discrete element method (DEM) with consideration of the incipiency of bedding planes. Laboratory experiments were conducted to quantify the direct tensile strength of the incipient bedding planes, and the results were used to calibrate the numerical model. The effects of bedding planes with different relative positions and spacing were discussed. A comparison between the simulated results of this study and the predicted results from failure criteria was completed, and a good agreement was observed.

关键词： Discrete element modelling particle flow code Incipient bedding planes Direct tensile strength Transverse isotropy Degree of anisotropy

来源：评论

学校读者我要写书评

暂无评论

A low energy rock fragmentation technique for in-situ leaching

引用

JOURNAL OF CLEANER PRODUCTION 2018年 204卷 586-606页

作者： De Silva, V. R. S. Ranjith, P. G. Perera, M. S. A. Wu, B. Wanniarachchi, W. A. M. Monash Univ Dept Civil Engn Deep Earth Energy Lab Bldg 60 Clayton Vic 3800 Australia Univ Melbourne Fac Engn Dept Infrastruct Engn Engn Block BGrattan St Parkville Vic 3010 Australia CSIRO Energy 71 Normanby Rd Clayton Vic 3169 Australia

Because over 60% of the total energy consumed in conventional mining consists of excavating, hauling, and liberating processes, the energy consumption in conventional methods of mining has increased exponentially with the decline in global ore-grades. In-situ leaching (ISL) is an alternative mining technology, which eliminates these processes. However, ISL is currently limited to porous rock. Expansion of ISL to impervious mineral bearing rocks requires controlled, artificial fracture stimulation and the current practice of hydraulic fracturing is not compatible due to the associated environmental impacts and uncontrolled fracture propagation. Therefore, to extend the application of ISL to impervious rocks, an alternative fracturing method using Soundless Cracking Demolition Agents (SCDAs), which is capable of producing controlled fractures in a rock mass, is proposed in this study. With the aim of understanding the fracturing performance of SCDA under in-situ stress conditions prevalent in ISL environments, a 3D numerical model for SCDA charging was produced using particle flow code (PFC3D 5.0) and validated with experimentally obtained data. The model was then extended to investigate the fracture mechanism of SCDA charging at various confining pressures of 5, 10, 15, and 20 MPa. Simulation results suggest that during SCDA charging, the number of radial fracture propagations and the total fracture damage in the rock mass increase with the confinement and the fracture pattern is dependent on the confining stress of the surrounding rock. In comparison to a hydraulically fractured specimen with identical dimensions, the fracture density of SCDA charged specimen showed a ten-fold increase at high confining pressures (20 MPa). Furthermore, as opposed to an uncontrolled, unidirectional diametrical fracture generated by hydraulic fracturing, SCDA charging produces multiple radial fractures around the injection well facilitating better spatial distribution of fluid flow fo

关键词： Mineral extraction in in-situ leaching particle flow code Numerical simulation Soundless cracking demolition agents (SCDAs) SCDA charged fracture mechanism Confinement effect

来源：评论

学校读者我要写书评

暂无评论

A study on drum cutting properties with full-scale experiments and numerical simulations

引用

MEASUREMENT 2018年 114卷 25-36页

作者： Li, Xuefeng Wang, Shibo Ge, Shirong Malekian, Reza Li, Zhixiong Li, Yifei China Univ Min & Technol Sch Mech Engn Xuzhou 221000 Peoples R China China Univ Min & Technol Collaborat Innovat Ctr Intelligent Min Equipment Xuzhou 221000 Peoples R China Univ Pretoria Dept Elect Elect & Comp Engn ZA-0002 Pretoria South Africa Univ New South Wales Sch Mech & Mfg Engn Sydney NSW 2052 Australia Iowa State Univ Dept Mech Engn Ames IA 50011 USA

In order to investigate the properties of cutting loads on shearer drum, a series of full-scale shearer drum cutting tests were conducted in the National Energy Coal Mining Machinery Equipment Research and Design Center of China. The pick forces and the torque acting on the drum were measured and recorded under different cutting conditions by the strain sensors that were embedded in the cutting picks. Besides, an attempt was made to simulate the shearer drum cutting process. For this purpose, a computer program named particle flow code in three dimensions (PFC3D) based on discrete element method (DEM) was used. The rock sample was models by graded particle assemblies and the micro-properties were calibrated by modeling the uniaxial compressive strength tests. The cutting process for the front and back drums with different traction speeds were simulated with this model. The torque of drums and forces of each pick were obtained during the simulation. Reasonable agreement and significant correlations were found between experiment and numerical simulation in terms of cutting forces of picks and the mean torque of the drums. The specific energy increased with the increase of traction speed in experiments, which was reproduced well in numerical simulation. Moreover, according to the analysis in frequency domain, the vibration of drum torque consists of components with multiple frequencies below 50 Hz, which is observed in both experiment and simulation. Therefore, numerical simulation by PFC3D is an easier, faster and reasonable method in the prediction of drum cutting load and design of shearer drum.

关键词： Drum cutting Full-scale experiment particle flow code Numerical simulation

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：