检索结果-南通市图书馆

Determination of the coefficient of rolling friction of an irregularly shaped maize particle group using physical experiment and simulations

引用

Particuology 2018年第3期16卷 185-195页

作者： Lijun Wang Rui Li Baoxin Wu ZhenchaoWu Zhenjun Ding College of Engineering Northeast Agricultural University Heilongjiang 150030 China

The coefficient of rolling friction is an important physical property of a maize particle. It is difficult to obtain the value of this coefficient because of the irregular shape of maize particles. This paper describes an approach that combines the discrete-element method （DEM） and a physical test to determine the coefficient of rolling friction of irregularly shaped maize particles. A novel test platform was used to obtain the maize particle＇s coefficient of restitution and the coefficient of static friction. EDEM software （DEM- Solutions, United Kingdom） was used to simulate the accumulation of maize particles on particles and on a zincified plate. The golden-section method was used to determine the range of the maize particle＇s coefficient of roiling friction. A single-factor test was used to determine the relationship between the maize particle＇s coefficient of rolling friction and their angle of repose. The results obtained from the EDEM simulation were compared with physical test results to determine the intergranular coefficient of rolling friction and the coefficient of roiling friction between maize particles and the zincified plate. Our study demonstrates that the angle of repose increases linearly with the coefficient of rolling friction of maize particles. The effect of the coefficient of rolling friction on the particle movement is studied. The physical verification test indicates that the obtained rolling friction of the maize particles is accurate. The findings of this paper provide a theoretical basis for maize-processing machine design and a discrete-element studv of the motion of maize particles inside such machines.

关键词： Coefficient of rolling friction Irregularly shaped particle Accumulation Simulation Golden-section method physical experiment

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Three-Dimensional Finite Element Numerical Simulation and physical experiment for Magnetism-Stress Detecting in Oil Casing

引用

Journal of Ocean University of China 2015年第4期14卷 669-674页

作者： MENG Fanshun ZHANG Jie YANG Chaoqun YU Weizhe CHEN Yuxi College of Marine Geo-science Ocean University of China Shenzhen Branch Company of China National Offshore Oil Corporation

The casing damage has been a big problem in oilfield production. The current detection methods mostly are used after casing damage, which is not very effective. With the rapid development of China's offshore oil industry, the number of offshore oil wells is becoming larger and larger. Because the cost of offshore oil well is very high, the casing damage will cause huge economic losses. What's more, it can also bring serious pollution to marine environment. So the effective methods of detecting casing damage are required badly. The accumulation of stress is the main reason for the casing damage. Magnetic anisotropy technique based on counter magnetostriction effect can detect the stress of casing in real time and help us to find out the hidden dangers in time. It is essential for us to prevent the casing damage from occurring. However, such technique is still in the development stage. Previous studies mostly got the relationship between stress and magnetic signals by physical experiment, and the study of physical mechanism in relative magnetic permeability connecting the stress and magnetic signals is rarely reported. The present paper uses the ANSYS to do the three-dimensional finite element numerical simulation to study how the relative magnetic permeability works for the oil casing model. We find that the quantitative relationship between the stress' s variation and magnetic induction intensity's variation is: Δδ =K* ΔB, K = 8.04×109, which is proved correct by physical experiment.

关键词： oil casing damage magnetism-stress detecting magnetic anisotropy finite element analysis physical experiment relative magnetic permeability ANSYS three-dimensional numerical simulation

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Designing physical experiment about characters of fuel cells

引用

International Journal of Technology Management 2017年第5期 56-58页

作者： Fuxin Li Tianjin Sino-German University of Applied Sciences Tianjin 300350 China

Currently, proton exchange membrane fuel cells are the most widely used fuel cell technology, In this article the function of fuel cells is briefly introduced. Certain characters of fuel cells are investigated through measuring the relation between electric current, voltage and product. A series of physics experiments using fuel cells is designed.

关键词： fuel cell electrolytic cell Proton Exchange Membrane physical experiment

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Simple analytical model for depth-averaged velocity in meandering compound channels

引用

Applied Mathematics and Mechanics(English Edition) 2015年第6期36卷 707-718页

作者： Yuqi SHAN Chao LIU Maokang LUO College of Mathematics Sichuan University State Key Laboratory of Hydraulics and Mountain River Engineering Sichuan University College of Water Resource and Hydropower Sichuan University

A simple but applicable analytical model is presented to predict the lat- eral distribution of the depth-averaged velocity in meandering compound channels. The governing equation with curvilinear coordinates is derived from the momentum equation and the flow continuity equation under the condition of quasi-uniform flow. A series of experiments are conducted in a large-scale meandering compound channel. Based on the experimental data, a magnitude analysis is carried out for the governing equation, and two lower-order shear stress terms are ignored. Four groups of experimental data from different sources are used to verify the predictive capability of this model, and good predictions are obtained. Finally, the determination of the velocity parameter and the limitation of this model are discussed.

关键词： meandering compound channel simple analytical model lateral distribu-tion method physical experiment depth-averaged velocity

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Tight sandstone gas accumulation mechanisms and sweet spot prediction, Triassic Xujiahe Formation, Sichuan Basin, China

引用

Petroleum Science 2023年第6期20卷 3301-3310页

作者： Lin Jiang Wen Zhao Dong-Mei Bo Feng Hong Yan-Jie Gong Jia-Qing Hao Research Institute of Petroleum Exploration and Development PetroChinaBeijing100083China

The prediction of continental tight sandstone gas sweet spots is an obstacle during tight sandstone gas exploration. In this work, the classic physical fluid charging experimental equipment is improved, the combination of the gas migration and accumulation process with the pore network numerical simulation method is investigated, and application of the permeability/porosity ratio is proposed to predict the gas saturation and sweet spots of continental formations. The results show that (1) as the charging pressure increases, the permeability of the reservoir increases because more narrow pore throats are displaced in the percolation process;and (2) based on pore network numerical simulation and theoretical analysis, the natural gas migration and accumulation mechanisms are revealed. The gas saturation of tight sandstone rock is controlled by the gas charging pressure and dynamic percolation characteristics. (3) The ratio of permeability/porosity and fluid charging pressure is proposed to predict the gas saturation of the formation. The ratio is verified in a pilot and proven to be applicable and practical. This work highlights the tight sandstone gas migration and accumulation mechanisms and narrows the gap among microscale physical experiments, numerical simulation research, and field applications.

关键词： Tight sandstone gas Hydrocarbon migration and accumulation physical experiment Numerical simulation

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Hydrodynamic Performance of A Dual-Floater Integrated System Com-bining Hybrid WECs and Floating Breakwaters

引用

China Ocean Engineering 2022年第6期36卷 969-979页

作者： FU Lei CHENG Yong School of Naval Architecture and Ocean Engineering Jiangsu University of Science and TechnologyZhenjiang 212100China

The high investment and low return of wave energy converters(WECs)seriously hamper their large-scale commercial *** integration of WECs and floating breakwaters is conducive to enhance the competitiveness of wave energy *** objective of this paper is to investigate the hydrodynamic performance of a WEC-breakwater integrated system combining an upstream oscillating water column(OWC)and a downstream oscillating buoy(OB)via numerical simulations and physical experiments.A nonlinear numerical wave flume using Star-CCM+software is employed to obtain calculated results,where a tiny transverse gap is set between the flume wall and the block surface to simulate a similar two-dimensional(2D)*** corresponding physical experiments are also carried out in a practical wave flume to verified the numerical *** comparison of the isolated and hybrid system shows that the hybrid design leads to the decreased conversion efficiency of each WEC,but improves the transmission performance of the hybrid *** wave resonance between two devices causes the abrupt reduction of OWC efficiency and a positive correlation exists with the OB *** total efficiency of the hybrid system is raised by an optimal opening ratio,a shallow OWC draft and a short spacing *** for the OWC draft,other design parameters have weak effect on the wave attenuation of the hybrid *** paper can help understand hydrodynamics of the hybrid WECs integrated with breakwaters and improve their performances.

关键词： wave energy converters floating breakwater oscillating buoy oscillating water column numerical wave flume physical experiment

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

The influence of perforated plates on wave transmission and hydrodynamic performance of pontoon floating breakwater

引用

Journal of Hydrodynamics 2018年第3期30卷 522-530页

作者： Chun-yan Ji Xiang Chen Xiao-jian Ma Zhiming Yuan School of Naval Architecture and Ocean Engineering Jiangsu University of Science and Technology Zhenjiang 212003 China Department of Naval Architecture Ocean and Marine Engineering.University of Strathclyde Glasgow UK

In this study, a perforated pontoon floating breakwater（FB） consisting of an impermeable plate and a perforated plate was designed to untangle the effect of a perforated plate on wave transmission and hydrodynamic performance of floating breakwater. A series of 2-D physical model experiments were conducted to measure the wave transmission coefficient, tension acting on the mooring line, and motion response of FB under a regular wave. The experimental results of the motion responses and mooring lines indicated that the new perforated plate was evidently effective. Furthermore, the study also discussed and analyzed the influence of the perforated plate on transmission coefficients. The experimental results showed that the new perforated plate did not lead to obvious improvement in the transmission performance

关键词： Floating breakwater perforated plates physical experiment wave transmission coefficient motion responses

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

experimental Investigation of Wave Load and Run-up on the Composite Bucket Foundation Influenced by Regular Waves

引用

Journal of Ocean University of China 2021年第2期20卷 271-284页

作者： YU Tongshun ZHAO Zishuai SHI Zhongyu XU Yu College of Engineering Ocean University of ChinaQingdao 266100China Shandong Provincial Key Laboratory of Ocean Engineering Qingdao 266100China State Key Laboratory of Hydraulic Engineering Simulation and Safety Tianjin UniversityTianjin 300072China

In the design of wind turbine foundations for offshore wind farms, the wave load and run-up slamming on the supporting structure are the quantities that need to be considered. Because of a special arc transition, the interaction between the wave field and the composite bucket foundation(CBF) becomes complicated. In this study, the hydrodynamic characteristics, including wave pressure, load, upwelling, and run-up, around the arc transition of a CBF influenced by regular waves are investigated through physical tests at Shandong Provincial Key Laboratory of Ocean Engineering, Ocean University of China. The distributions of the wave pressures and upwelling ratios around the CBF are described, and the relationship between the wave load and the wave parameters is discussed. New formulae based on the velocity stagnation head theory with linear wave theory and the second-order Stokes wave theory for wave kinematics are proposed to estimate the wave run-up. Moreover, the multiple regression method with nonlinear technology is employed to deduce an empirical formula for predicting run-up heights. Results show that the non-dimensional wave load increases with the increase in the values of the wave scattering parameter and relative wave height. The wave upwelling height is high in front of the CBF and has the lowest value at an angle of 135? with the incoming wave direction. The performance of the new formulae proposed in this study is compared using statistical indices to demonstrate that a good fit is obtained by the multiple regression method and the analytical model based on the velocity stagnation head theory is underdeveloped.

关键词： physical experiment composite bucket foundation wave load wave run-up regular waves

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

A review of breaking wave force on the bridge pier: experiment, simulation, calculation, and structural response

引用

Journal of Traffic and Transportation Engineering(English Edition) 2022年第3期9卷 407-421页

作者： Kai Wei Jie Hong Mochen Jiang Wenyu Zhao School of Civil Engineering Southwest Jiaotong UniversityChengdu 610031China

In the course of the propagation of waves from the offshore to the nearshore zone, the wave may break due to the shoaling effect. Strong impact forces are observed when the breaking wave acts on the pier of the bridge. This impact force might not only change the dynamic load pattern on the pier but also cause strong structural vibration, which may threaten the driving and structural safety of the bridge. Many studies have been carried out to study the issues in the aspect of wave flume experiment, numerical simulation, calculation of breaking wave force, and random vibration response of the structure. Considering the studies of breaking wave load on bridge piers are lack of systematic summaries, this paper presents a comprehensive and up-to-date literature review of breaking wave research and practice related to bridges. Firstly, a brief introduction is given, which includes recent cases of bridge failures caused by breaking waves. Then, both scientific and technical studies are reviewed, categorized into four aspects: experimental study, numerical simulation, analytical calculation of breaking wave force, and the structural response under breaking wave. Finally, Discussion is provided on four emerging ideas to investigate breaking wave forces on the pier from both science and engineering perspectives.

关键词： Breaking wave Wave force physical experiment Numerical simulation Calculation method Vibration characteristics

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Gas-water stratified flow patterns from electromagnetic tomography

引用

Petroleum Science 2009年第3期6卷 254-258页

作者： Wang Xiaoxing Wu Xiling School of Resources and Information Technology China University of Petroleum Beijing 102249 China

Because of gravitational differentiation of multi-phase fluids, gas-water flow is usually stratified in highly inclined or horizontal gas wells. By using electrode arrays to scan flowing fluids, electromagnetic tomography can identify the flow patterns of mixed fluid from the different electrical properties of gas and water. The responses for different gas-water interface locations were calculated and then physical measurements were undertaken. We compared the results of the numerical simulation with the experimental data, and found that the response characteristics were consistent in the circumstances of uniform physical fields and stratified flows. By analyzing the signal characteristics, it is found that, with the change of the interface location, the response curves showed ＂steps＂ whose position and width were decided by the location of fluid interface. The measurement accuracy of this method depended on the vertical distance between adjacent electrodes. The results showed that computer simulation can simulate the measurement of the electromagnetic tomography accurately, so the physical experiment can be replaced.

关键词： Electromagnetic tomography stratified flow gas-water numerical simulation physical experiment

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

欢迎您,

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

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

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

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

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：