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Flow behavior of non-spherical particle flowing in hopper

He TAO,Wenqi ZHONG,Baosheng JIN

《能源前沿(英文)》 2014年 第8卷 第3期   页码 315-321 doi: 10.1007/s11708-014-0331-9

摘要: Ellipsoidal particles flowing in the hopper were simulated by using the discrete element method (DEM), and described by the multi-element method. The contact detection algorithm and equations for ellipsoidal particle motion in hopper were developed. And the simulation results were confirmed by experiment. Additionally, the mass flow rate, pressure distribution and velocity distribution of two kinds of particles were examined. The results show that the mass flow rate of ellipsoidal particles is smaller than that of spherical particles. There is a maximum value of pressure drop at the top of the junction. Besides, the pressure drop decreases with the discharging time increasing. The velocity of spherical particle is larger than that of ellipsoidal.

关键词: discrete element method     ellipsoidal particle     flow behavior     hopper    

Experimental investigation of multiphase flow behavior in drilling annuli using high speed visualization

Alap Ali ZAHID, Syed Raza ur REHMAN, Anwarul HASAN, S. RUSHD, Mohammad Azizur RAHMAN

《能源前沿(英文)》 2020年 第14卷 第3期   页码 635-643 doi: 10.1007/s11708-018-0582-y

摘要: Imaging with high definition video camera is an important technique to visualize the drilling conditions and to study the physics of complex multiphase flow associated with the hole cleaning process. The main advantage of visualizing multiphase flow in a drilling annulus is that the viewer can easily distinguish fluid phases, flow patterns and thicknesses of cutting beds. In this paper the hole cleaning process which involves the transportation of cuttings through a horizontal annulus was studied. The two-phase (solid-liquid) and the three-phase (solid-liquid-gas) flow conditions involved in this kind of annular transportation were experimentally simulated and images were taken using a high definition camera. Analyzing the captured images, a number of important parameters like velocities of different phases, heights of solid beds and sizes of gas bubbles were determined. Two different techniques based on an image analysis software and MATLAB coding were used for the determinations. The results were compared to validate the image analyzing methodology. The visualization technique developed in this paper has a direct application in investigating the critical conditions required for efficient hole cleaning as well as in optimizing the mud program during both planning and operational phases of drilling. Particularly, it would be useful in predicting the cuttings transport performance, estimating solid bed height, gas bubble size, and mean velocities of bubbles/particles.

关键词: visualization     horizontal annulus     hole cleaning     multiphase flow     image analysis     flow regime    

Experimental study on flow behavior at open channel confluences

WANG Xiekang, WANG Xianye, LU Weizhen, LIU Tonghuan

《结构与土木工程前沿(英文)》 2007年 第1卷 第2期   页码 211-216 doi: 10.1007/s11709-007-0025-z

摘要: Channel confluences are common in natural rivers and hydraulic engineering, and the flow behavior at confluences becomes very complex because of the interaction between the tributary and the main river. In this study, the experiments were performed in a combined flume with a 30º angle between the main and tributary flume located at Sichuan University. The velocity was measured by using a three-component acoustic Doppler velocimeter (ADV) over a grid defined throughout the junction region. Based on the analysis of the velocity at the confluence, the distinctive characteristics of a channel confluence flow may be divided into several zones including a zone of separation immediately downstream of the junction branch channel, the maximum and minimum velocity regions at the upstream and downstream in the confluent channel, and a shear plane developed between the two combining flows downstream of the confluent channel. In addition, secondary circulations in different directions at the higher and lower velocity zones are observed as well.

关键词: ADV     different     interaction     separation     downstream    

Flow behavior of liquid-solid coupled system of piezoelectric micropump

LU Lijun, WU Jiankang

《机械工程前沿(英文)》 2008年 第3卷 第1期   页码 50-54 doi: 10.1007/s11465-008-0003-8

摘要: This paper employs a shallow water model and the finite element method to approximate periodical flows of a micropump to a two-dimensional thickness-averaged flow. A liquid-solid coupled system equation of the micropump is presented. Through the mode analysis of the liquid-solid coupled system, the first-order natural frequency, diaphragm vibration shape and amplitude-frequency relationship are obtained. The vibration response of the diaphragm is calculated when an external electric field is applied. Based on the thickness-averaged flow equation, the periodical flow of the micropump is studied using the finite volume method to investigate the flow behavior and flow rate-frequency characteristics. Numerical results indicate that an optimal working frequency can be obtained, at which the flow rate of the micropump achieves the maximum when the external electric voltage is fixed.

关键词: amplitude-frequency relationship     first-order     micropump     diaphragm vibration     electric    

Chebyshev多项式在锚链分析中的应用

滕斌,郝春玲,韩凌

《中国工程科学》 2005年 第7卷 第1期   页码 21-26

摘要:

依据水流作用下锚链的数值分析模型,提出了应用Chebyshev多项式拟合建立锚链张力与锚链顶端位置函数关系的近似方法,该锚链函数多项式可方便地用于波浪与锚泊结构物相互作用的实时模拟中。计算中按静水和有流两种情况,应用二维和三维Chebyshev多项式,建立了锚链顶端水平和垂向拉力与锚链顶端水平、垂向位置,及水流速度的函数关系。锚链分析模型采用分段外推-校正方法计算,在无流、均质锚链情况下,计算结果与解析解完全吻合。

关键词: 锚链张力     锚链位移     Chebyshev多项式    

New approach to determine the plastic viscosity of self-compacting concrete

M. BENAICHA,X. ROGUIEZ,O. JALBAUD,Y. BURTSCHELL,A. Hafidi ALAOUI

《结构与土木工程前沿(英文)》 2016年 第10卷 第2期   页码 198-208 doi: 10.1007/s11709-015-0327-5

摘要: The rheology of concrete is best measured with the use of a rheometer. The slump flow test gives a good indication of the flowability of the mixture and is therefore still used extensively to judge the workability of SCC mixtures. However, this test presents some defects. The objective of this paper is to develop a new methodology for measuring the workability of a SCC. In this article, we have proposed a correlation between the plastic viscosity of concrete, the time and the characteristics of the flow final profile from the V-funnel coupled to a Plexiglas horizontal channel. The proposed approach, verified by experimental results, represents a simple, economical and usable tool on building site, and it allows to characterize rheologically the SCC from its flow. The comparison between our approach and the experimental values of the plastic viscosity shows that, in a laboratory or on site, instead of using a rheometer we can use our approach to characterize the rheological behavior of a SCC.

关键词: rheology     viscosity     V-funnel     flow profile     rheometer     behavior    

Numerical study of internal flow field and flow passage improvement of an inlet particle separator

Florian PAOLI, Tong WANG

《能源前沿(英文)》 2011年 第5卷 第4期   页码 386-397 doi: 10.1007/s11708-011-0156-8

摘要: By performing gas flow field numerical simulations for several inlet Reynolds numbers (from 2 × 10 to 9 × 10 ) and byflow ratios (from 10% to 20%), the present study has proposed to improve the flow passage of an inlet particle separator. An adjacent objective of the study is to lower pressure losses of the inlet particle separator (IPS). No particle has been included in the gas flow for a -epsilon turbulence model. The velocity distribution in different sections and the pressure coefficient along the duct have been analyzed, which indicates that there exist important low-velocity regions and vortices in the separation area. Therefore, the profile of streamlines along the original passage has been considered. This profile illustrated a vacuum region in the same area. All investigations suggest that the separation area is the most critical one for fulfilling the objective on pressure losses limitation. Then the flow passage improvement method has focused on the separation area. An improved shape has been designed in order to suit smoothly to the streamlines in this region. Similar numerical studies as those for the original shape have been conducted on this improved shape, confirming some considerable enhancements compared with the original shape. The significant vortices which appear in the original shape reduce in amount and size. Besides, pressure losses are greatly decreased in both outlets (up to 30% for high Reynolds number) and the flow is uniform at the main outlet. Subsequent engineering surveys could rely on expressions obtained for in both outlets which extend the pressure losses for a wide range of inlet Reynolds numbers. As a result, the numerical calculations demonstrate that the flow passage improvement method applied in this study has succeeded in designing a shape which enhances the flow behavior.

关键词: streamlines     pressure losses     flow passage improvement     inlet particle separator (IPS)    

Study on Big Data-based Behavior Modification in Metro Construction

Lie-yun Ding,Sheng-yu Guo

《工程管理前沿(英文)》 2015年 第2卷 第2期   页码 131-136 doi: 10.15302/J-FEM-2015037

摘要: With the rapid development of metro construction in China, construction accidents frequently happen, which are significantly attributable to workers’ unsafe behavior. Behavior-based safety (BBS) is an effective method to modify workers’ unsafe behavior. This paper introduces the study on big data-based metro construction behavior modification, aiming to solve the problem of current research without consideration of workers’ personal characters. First, the behavior modification pushing mechanism based on content-based personalized recommendation is studied. Secondly, the development of behavior modification system of metro construction (BMSMC) is introduced. Thirdly, BMSMC practical applications using the unsafe behavior rate, as a measuring indicator is implemented. Observations at one metro construction site in Wuhan indicate that the unsafe behavior rate of modified scaffolders at this work place decreased by 69.3%. At the same time, as of unmodified scaffolders at another work place for comparison, the unsafe behavior rate decreased by 56.9%, which validates the effectiveness of this system.

关键词: big data     unsafe behavior     behavior modification     behavior-based safety (BBS)     unsafe behavior rate    

A simplified method for investigating the bending behavior of piles supporting embankments on soft ground

《结构与土木工程前沿(英文)》   页码 1021-1032 doi: 10.1007/s11709-023-0952-3

摘要: In recent years, concrete and reinforced concrete piles have been widely used to stabilize soft ground under embankments. Previous research has shown that bending failure, particularly during rapid filling on soft ground, is the critical failure mode for pile-supported embankments. Here, we propose an efficient two-stage method that combines a test-verified soil deformation mechanism and Poulos’ solution for pile–soil interaction to investigate the bending behavior of piles supporting embankments on soft ground. The results reveal that there are three possible bending failure scenarios for such piles: at the interface between the soft and firm ground layers, at mid-depths of the fan zone, and at the boundary of the soil deformation mechanism. The location of the bending failure depends on the position and relative stiffness of the given pile. Furthermore, the effect of embedding a pile into a firm ground layer on the bending behavior was investigated. When the embedded length of a pile exceeded a critical value, the bending moment at the interface between the soft and firm ground layers reached a limiting value. In addition, floating piles that are not embedded exhibit an overturning pattern of movement in the soft ground layer, and a potential failure is located in the upper part of these piles.

关键词: bending behavior     pile     embankment     soil−structure interaction     failure mode    

Weakening behavior of waterproof performance in joints of shield tunnels under adjacent constructions

《结构与土木工程前沿(英文)》   页码 884-900 doi: 10.1007/s11709-022-0912-3

摘要: Groundwater leakage in shield tunnels poses a threat to the safety and durability of tunnel structures. Disturbance of adjacent constructions during the operation of shield tunnels frequently occurs in China, leading to deformation of tunnel lining and leakage in joints. Understanding the impact of adjacent constructions on the waterproofing performance of the lining is critical for the protection of shield tunnels. In this study, the weakening behavior of waterproof performance was investigated in the joints of shield tunnels under transverse deformation induced by adjacent construction. First, the relationship between the joint opening and transverse deformation under three typical adjacent constructions (upper loading, upper excavation, and side excavation) was investigated via elaborate numerical simulations. Subsequently, the evolution of the waterproof performance of a common gasket with a joint opening was examined by establishing a coupled Eulerian–Lagrangian model of joint seepage, and a formula describing the relationship between waterproof performance and joint opening was proposed. Finally, the weakening law of waterproofing performance was investigated based on the results of the aforementioned studies. It was determined that the joints with the greatest decline in waterproof performance were located at the tunnel shoulder in the upper loading case, tunnel crown in the upper excavation case, and tunnel shoulder in the side excavation case. When the waterproof performance of these joints decreased to 50% and 30%, the transverse deformations were 60 and 90 mm under upper loading, 90 and 140 mm under upper excavation, and 45 and 70 mm under side excavation, respectively. The results provide a straightforward reference for setting a controlled deformation standard considering the waterproof performance.

关键词: shield tunnel     waterproof performance     horizontal transverse deformation     joint opening     weakening behavior    

Effects of herding behavior of tradable green certificate market players on market efficiency: Insights

《能源前沿(英文)》 2023年 第17卷 第2期   页码 266-285 doi: 10.1007/s11708-021-0752-1

摘要: Tradable green certificate (TGC) scheme promotes the development of renewable energy industry which currently has a dual effect on economy and environment. TGC market efficiency is reflected in stimulating renewable energy investment, but may be reduced by the herding behavior of market players. This paper proposes and simulates an artificial TGC market model which contains heterogeneous agents, communication structure, and regulatory rules to explore the characteristics of herding behavior and its effects on market efficiency. The results show that the evolution of herding behavior reduces information asymmetry and improves market efficiency, especially when the borrowing is allowed. In addition, the fundamental strategy is diffused by herding evolution, but TGC market efficiency may be remarkably reduced by herding with borrowing mechanism. Moreover, the herding behavior may evolve to an equilibrium where the revenue of market players is comparable, thus the fairness in TGC market is improved.

关键词: tradable green certificate     herding behavior     evolution     heterogeneous agent model     complex network    

物质流分析的跟踪观察法

陆钟武

《中国工程科学》 2006年 第8卷 第1期   页码 18-25

摘要:

流动,是物质(如铜、铝等)流动和流体流动二者所具有的基本特征,基于这个论点,简要地回顾了流体力学中研究流体流动的两种方法,即拉格朗日法和欧拉法;相应地提出了物质流分析的两种方法,即跟踪观察法和定点观察法。由于前者在文献中未见报道,因此对它进行了重点说明。强调了物质流的跟踪观察法既适用于稳态物质流(产品产量不变),也适用于非稳态物质流(产品产量增长或下降)。以钢铁产品生命周期的铁流图为例,说明了物质流的跟踪模型。在引入了物质流的非稳度后,提出了物质流各项指标的计算式,以及它们之间的相互关系。以瑞典铅酸电池系统为对象,计算了其中铅流的各项指标,并进行了必要的分析。

关键词: 物质流的研究方法     物质流的跟踪观察法     物质流的基本公式     物质流的非稳度    

UPFC setting to avoid active power flow loop considering wind power uncertainty

Shenghu LI, Ting WANG

《能源前沿(英文)》 2023年 第17卷 第1期   页码 165-175 doi: 10.1007/s11708-020-0686-z

摘要: The active power loop flow (APLF) may be caused by impropriate network configuration, impropriate parameter settings, and/or stochastic bus powers. The power flow controllers, e.g., the unified power flow controller (UPFC), may be the reason and the solution to the loop flows. In this paper, the critical existence condition of the APLF is newly integrated into the simultaneous power flow model for the system and UPFC. Compared with the existing method of alternatively solving the simultaneous power flow and sensitivity-based approaching to the critical existing condition, the integrated power flow needs less iterations and calculation time. Besides, with wind power fluctuation, the interval power flow (IPF) is introduced into the integrated power flow, and solved with the affine Krawcyzk iteration to make sure that the range of active power setting of the UPFC not yielding the APLF. Compared with Monte Carlo simulation, the IPF has the similar accuracy but less time.

关键词: active power loop flow (APLF)     unified power flow controller (UPFC)     wind power uncertainty     interval power flow (IPF)    

A novel flow electrode capacitive deionization device with spindle-shaped desalting chamber

《环境科学与工程前沿(英文)》 2023年 第18卷 第4期 doi: 10.1007/s11783-024-1800-y

摘要:

● A spindle-shaped influent chamber was designed and equipped in FCDI system.

关键词: Spindle-shaped chamber     Desalination performance     Flow electrode capacitive deionization    

Adsorption behavior of antibiotic in soil environment: a critical review

Shiliang WANG,Hui WANG

《环境科学与工程前沿(英文)》 2015年 第9卷 第4期   页码 565-574 doi: 10.1007/s11783-015-0801-2

摘要: Antibiotics are used widely in human and veterinary medicine, and are ubiquitous in environment matrices worldwide. Due to their consumption, excretion, and persistence, antibiotics are disseminated mostly via direct and indirect emissions such as excrements, sewage irrigation, and sludge compost and enter the soil and impact negatively the natural ecosystem of soil. Most antibiotics are amphiphilic or amphoteric and ionize. A non-polar core combined with polar functional moieties makes up numerous antibiotic molecules. Because of various molecule structures, physicochemical properties vary widely among antibiotic compounds. Sorption is an important process for the environment behaviors and fate of antibiotics in soil environment. The adsorption process has decisive role for the environmental behaviors and the ultimate fates of antibiotics in soil. Multiply physicochemical properties of antibiotics induce the large variations of their adsorption behaviors. In addition, factors of soil environment such as the pH, ionic strength, metal ions, and organic matter content also strongly impact the adsorption processes of antibiotics. Review about adsorption of antibiotics on soil can provide a fresh insight into understanding the antibiotic-soil interactions. Therefore, literatures about the adsorption mechanisms of antibiotics in soil environment and the effects of environment factors on adsorption behaviors of antibiotics in soil are reviewed and discussed systematically in this review.

关键词: adsorption     antibiotics     environment factors     soil    

标题 作者 时间 类型 操作

Flow behavior of non-spherical particle flowing in hopper

He TAO,Wenqi ZHONG,Baosheng JIN

期刊论文

Experimental investigation of multiphase flow behavior in drilling annuli using high speed visualization

Alap Ali ZAHID, Syed Raza ur REHMAN, Anwarul HASAN, S. RUSHD, Mohammad Azizur RAHMAN

期刊论文

Experimental study on flow behavior at open channel confluences

WANG Xiekang, WANG Xianye, LU Weizhen, LIU Tonghuan

期刊论文

Flow behavior of liquid-solid coupled system of piezoelectric micropump

LU Lijun, WU Jiankang

期刊论文

Chebyshev多项式在锚链分析中的应用

滕斌,郝春玲,韩凌

期刊论文

New approach to determine the plastic viscosity of self-compacting concrete

M. BENAICHA,X. ROGUIEZ,O. JALBAUD,Y. BURTSCHELL,A. Hafidi ALAOUI

期刊论文

Numerical study of internal flow field and flow passage improvement of an inlet particle separator

Florian PAOLI, Tong WANG

期刊论文

Study on Big Data-based Behavior Modification in Metro Construction

Lie-yun Ding,Sheng-yu Guo

期刊论文

A simplified method for investigating the bending behavior of piles supporting embankments on soft ground

期刊论文

Weakening behavior of waterproof performance in joints of shield tunnels under adjacent constructions

期刊论文

Effects of herding behavior of tradable green certificate market players on market efficiency: Insights

期刊论文

物质流分析的跟踪观察法

陆钟武

期刊论文

UPFC setting to avoid active power flow loop considering wind power uncertainty

Shenghu LI, Ting WANG

期刊论文

A novel flow electrode capacitive deionization device with spindle-shaped desalting chamber

期刊论文

Adsorption behavior of antibiotic in soil environment: a critical review

Shiliang WANG,Hui WANG

期刊论文