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Chinese Science Bulletin 2013年第7期58卷 666-676页

作者： CHEN YiKai HE Jie KING Mark CHEN WuWei ZHANG WeiHua School of Transportation Engineering Hefei University of Technology Traffic Management Research institute of the Ministry of Public Security School of Transportation Southeast University Centre for Accident Research and Road Safety-Queensland Queensland University of TechnologyKelvin Grove 4059Australia School of Mechanical and Automotive Engineering Hefei University of Technology

The objective of this research was to investigate the effects of driving conditions and suspension parameters on dynamic load-sharing of longitudinal-connected air suspensions of a tri-axle semi-trailer.A novel nonlinear model of a multi-axle semi-trailer with longitudinal-connected air suspension was formulated based on fluid mechanics and thermodynamics and was validated through test *** effects of driving conditions and suspension parameters on dynamic load-sharing and road-friendliness of the semi-trailer were *** results indicate that the road-friendliness metric-DLC(dynamic load coefficient) is not always in accordance with the load-sharing metric-DLSC(dynamic load-sharing coefficient).The effect of employing larger air lines and connectors on the DLSC optimization ratio gives varying results as road roughness increases and as driving speed *** the vehicle load reduces,or the static pressure increases,the DLSC optimization ratio declines *** results also indicate that if the air line diameter is always assumed to be larger than the connector diameter,the influence of air line diameter on load-sharing is more significant than that of the connector.

关键词：空气悬架负载共享悬挂参数驾驶条件多轴半挂车负载分担管路直径纵向连接

Particle breakage of sand subjected to friction and collision in drum tests

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Journal of Rock mechanics and Geotechnical Engineering 2021年第2期13卷 390-400页

作者： Fangwei Yu Chonglei Zhang Qijun Xie Lijun Su Tao Zhao M.Qasim Jan Key Laboratory of Mountain Hazards and Earth Surface Process of CAS Institute of Mountain Hazards and EnvironmentChinese Academy of SciencesChengdu610041China Center for Excellence in Tibetan Plateau Earth Sciences Chinese Academy of SciencesBeijing100101China China-Pakistan Joint Research Center on Earth Sciences CAS-HECIslamabad45320Pakistan Department of Civil Engineering The University of TokyoTokyo113-8656Japan University of Chinese Academy of Sciences Beijing100049China Department of Civil and Environmental Engineering Brunel University LondonLondonUB83PHUK National Centre of Excellence in Geology University of PeshawarPeshawar25130Pakistan

This paper presents a laboratory experimental study on particle breakage of sand subjected to friction and collision,by a number of drum tests on granular materials(silica sand No.3 and ceramic balls)to investigate the characteristics of particle breakage and its effect on the characteristics of grain size distribution of *** breakage increased in up convexity with increasing duration of drum tests,but increased linearly with increasing number of *** breakage showed an increase,followed by a decrease while increasing the amount of *** may be existence of a characteristic amount of sand causing a maximum particle *** tests caused much less particle breakage than collision tests *** and collision resulted in different mechanisms of particle breakage,mainly by abrasion for friction and by splitting for *** fines content increased with increasing relative *** breakage in the friction tests(abrasion)resulted in a sharper increase but with a smaller total amount of fines content in comparison with that in the collision tests(splitting).For the collision tests,the fines content showed a decrease followed by an increase as the amount of sand increased,whereas it increased in up convexity with increasing number of *** characteristic grain sizes D_(10) and D_(30) decreased in down convexity with increasing relative breakage,which could be described by a natural exponential ***,the characteristic grain sizes D50 and D60 decreased linearly while increasing the relative *** addition,the coefficients of uniformity and curvature of sand showed an increase followed by a decrease while increasing the relative breakage.

关键词： Grain size distribution Drum tests Granular flow Particle breakage

Ameliorating Model Representation with the Sophisticated Advection Schemes

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Ameliorating Model Representation with the Sophisticated Adv...

Regular perturbation solution of Couette flow(non-Newtonian)between two parallel porous plates: a numerical analysis with irreversibility

The Sixth World Congress on Computational mechanics in Conjunction with the Second Asian-Pacific Congress on Computational mechanicsⅠ

作者： Keiko Takahashi Takashi Yabe Earth Simulator Center JAMSTEC 3173-25 Showa-machi Kanazawa-ku Yokohama 236-0001 Japan Department of Mechanical Engineering and Science Tokyo institute of Technology 2-12-1 O-okayama Meguro-ku 152-8550

Advection acts import in the fluid dynamics, also in the computational mechanics for a variety of scientific phenomena. Low-order finite differencing schemes show simple algorithm and cheap computation, but diffusive. High-order schemes illustrate to be oscillatory. Both are tightly restricted by the Courant number. The attempt of introducing a class of semi-Lagrangian methods, which is known as CIP [1] (Cubic Interpolated Pseudoparticle), to atmospheric models is presented in this paper, with some real-case simulations and idealized tests.

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Applied Mathematics and mechanics(English Edition) 2021年第1期42卷 127-142页

作者： M.NAZEER M.I.KHAN S.KADRY Yuming CHU F.AHMAD W.ALI M.IRFAN M.SHAHEEN Department of Mathematics Institute of Arts and SciencesGovernment College UniversityChiniot CampusFaisalabad 35400Pakistan Department of Mathematics and Statistics Riphah International University I-14Islamabad 44000Pakistan Department of Mathematics and Computer Science Beirut Arab UniversityBeirut 11-5020Lebanon Department of Mathematics Huzhou UniversityHuzhou 313000Zhejiang ProvinceChina Hunan Provincial Key Laboratory of Mathematical Modeling and Analysis in Engineering Changsha University of Science&TechnologyChangsha 410114China Department of Applied Sciences National Textile UniversityFaisalabad 38000Pakistan Chair of Production Technology Faculty of Engineering TechnologyUniversity of TwenteEnschede 7500 AEThe Netherlands Department of Mathematics Riphah Inernational LniversityFaisalabad CampusFaiselabad 38000Pakistan

The unavailability of wasted energy due to the irreversibility in the process is called the entropy *** irreversible process is a process in which the entropy of the system is *** second law of thermodynamics is used to define whether the given system is reversible or ***,our focus is how to reduce the entropy of the system and maximize the capability of the *** are many methods for maximizing the capacity of heat *** constant pressure gradient or motion of the wall can be used to increase the heat transfer rate and minimize the *** objective of this study is to analyze the heat and mass transfer of an Eyring-Powell fluid in a porous *** this,we choose two different fluid models,namely,the plane and generalized Couette *** flow is generated in the channel due to a pressure gradient or with the moving of the upper *** present analysis shows the effects of the fluid parameters on the velocity,the temperature,the entropy generation,and the Bejan *** nonlinear boundary value problem of the flow problem is solved with the help of the regular perturbation *** validate the perturbation solution,a numerical solution is also obtained with the help of the built-in command NDSolve of MATHEMATICA *** velocity profile shows the shear thickening behavior via first-order Eyring-Powell *** is also observed that the profile of the Bejan number has a decreasing trend against the Brinkman ***ηi→0(i=1,2,3),the Eyring-Powell fluid is transformed into a Newtonian fluid.

关键词： Couette flow Eyring-Powell fluid entropy generation perturbation method Bejan number

Gas Turbine Design and Matching Research of Waste Heat Recovery System for Marine Diesel Engine

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Journal of mechanics Engineering and Automation 2019年第6期9卷 203-210页

作者： Jiewei Peng Zijian Zhang Zhichao Gu Peijun Qin Shanghai Marine Diesel Engine Research institute Shanghai 200090China

With the emphasis on energy and environmental protection,energy-conservation and emission-reduction become vital issues for industrial ***,with the development of legislation on marine environment,the marine diesel engine has become focusing on energy saving and emission reduction for *** low-speed diesel engines under high load,waste heat from exhaust gas can be recovered by the compact and efficient gas *** this paper,the matching design research between low speed diesel engine and gas turbine is carried *** balance efficiency and compactness,the impeller was adjusted and generated by ANSYS BLADEGEN,based on 1D thermodynamic *** the 1D calculation is similar to the ANSYS CFX simulation result:the total-static efficiency is 73.8%compared to 76.7%.Moreover,the flow separation happened at the impeller suction side and created vortex due to the high incidence *** off-design operating point simulation of the turbine shows though the pressure ratio increase will cause the efficiency to decline a little,the total shaft power *** sum,this paper worked out a power turbine suitable for a low-speed diesel engine according to the turbine character matching design and simulation,which provides foundation to the construction of a steady operation of waste heat recovery system for marine diesel engine.

关键词： Waste heat recovery turbine design marine diesel engine CFX aerodynamic analysis.

Numerical Study of the Mixing of Density-Stratified fluid with a Jet

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Journal of mechanics Engineering and Automation 2014年第10期4卷 789-798页

作者： Shogo Shakouchi Seiji Shimada Tomomi Uchiyama Graduate School of Information Science Nagoya University Nagoya 464-8601 Japan Chubu Electric Power Co. Inc. Nagoya 461-8680 Japan Kawasaki Heavy Industries Ltd. Hyogo 650-8680 Japan EcoTopia Science institute Nagoya University Nagoya 464-8603 Japan

Density stratification of LNG （liquefied natural gas） is produced in a storage tank when one LNG is loaded on top of another LNG in the same tank. Mixing LNG by a jet issued from a nozzle on the tank wall is considered to a promising technique to prevent and eliminate stratification in LNG storage tanks. This study is concerned with the numerical simulation of a jet flow issued into a two-layer density-stratified fluid in a tank and the resultant mixing phenomena. The jet behavior was investigated with the laboratory-based experiment of the authors＇ previous study. A numerical method proposed by the authors is employed for the simulation. The upper and lower fluids are water and a NaCl-water solution, respectively, and the lower fluid is issued vertically upward from a nozzle on the bottom of the tank. The Reynolds number （Re） defined by the jet velocity and the nozzle diameter ranges from 95 to 2,378, and the mass concentration of the NaCl-water solution Co is set at 0.02 and 0.04. The simulation highlights the jet-induced mixing between the upper and lower fluids. It also clarifies the effects of Re and C0 on the height and horizontal spread of the jet.

关键词： Mixing density-stratified fluid jet CFD (computational fluid dynamics) internal density current.

Swirl Jets in Crossflow at Low Velocity Ratios

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Journal of mechanics Engineering and Automation 2012年第4期2卷 256-266页

作者： Alexandros Terzis Charilaos Kazakos Anestis I. Kalfas PavIos K. Zachos Peter Ott Group of Thermal Turbomachinery EPFL-SCI-STI-PO Swiss Federal Institute of Technology Lausanne CH-I O15 Switzerland School of Engineering Aristotle University ofThessaloniki Thessaloniki GR-54-124 Greece Department of Power and Propulsion Cranfield University Bedfordshire MK43 OAL UK

This investigation examines experimentally the behavior of swirled jets produced by axial flow fans blowing into a crossflow at low velocity ratios. The main difference with non-swirl cases is an asymmetry of the dominant kidney vortex and a slight distortion of the jet trace downstream of the injection hole. The effect of jet rotation at relatively low swirl numbers and similar velocity ratios is also investigated by a validated computational analysis tool. The numerical results are analyzed by means of various post-processing procedures, aiming to clarify, quantify and analyze the impact of swirl on the characteristics and the flow domain of a jet in crossflow. In general, swirl introduces an asymmetry in all examined quantities and prevents the penetration of the jet into the crossflow, causing the jet to remain closer to the wall surface. The rotation of the injected fluid results in an imparity of the two parts of the Counter Rotating Vortex Pair （CVP） which is no longer symmetric to the axial centerline plane. High swirl numbers result in the destruction of the CVP and the dominant kidney shape vortex is transformed into a comma shape vortex, rotating close to the wall.

关键词： Jet in crossflow swirl CFD (computational fluid dynamics).

一种可预测非饱和土壤中入渗和汇水的水力耦合模型

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Journal of Central South University 2023年第10期30卷 3435-3449页

作者：刘敏冯学茂赵炼恒宋祉辰胡世红戴智颖 School of Civil Engineering Central South UniversityChangsha 410075China Key Laboratory of Heavy-haul Railway Engineering Structure of Ministry of Education Central South UniversityChangsha 410075China Hunan Provincial Key Laboratory for Disaster Prevention and Mitigation of Rail Transit Engineering Structures Central South UniversityChangsha 410075China Shenzhen General Integrated Transportation and Municipal Engineering Design&Research institute Co. Ltd.Shenzhen 518003China

非饱和土壤在自然和工程实践中广泛存在,进一步了解非饱和多孔介质渗透过程中的水力耦合效应,对岩土工程和水文学界有着重要意义。本文提出一个非线性的完全水力耦合模型,用于控制可变形多孔介质中非饱和水的流动。该模型依赖于有限元(... 详细信息

非饱和土壤在自然和工程实践中广泛存在,进一步了解非饱和多孔介质渗透过程中的水力耦合效应,对岩土工程和水文学界有着重要意义。本文提出一个非线性的完全水力耦合模型,用于控制可变形多孔介质中非饱和水的流动。该模型依赖于有限元(FE)求解器来计算受瞬态流作用下土壤中的水力耦合响应。使用已有的水力耦合解析解和积水入渗试验数据作为参考,对模型模拟结果的准确性进行验证。模拟结果表明,该模型在非稳定降雨条件和地表积水条件下能够准确模拟出降雨过程中的土壤入渗量和地表汇水量。此外,分别考虑吸力弹性模量、渗透模型的控制参数、饱和渗透系数以及边坡角度四个因素的变化而进行入渗和汇水过程的模拟结果进一步表明,土壤的膨胀性延迟了孔隙水压力的增长,而土壤的湿陷性则促进了孔隙水压力的增长;土壤孔径分布越粗糙,水力耦合效应越明显;土壤饱和渗透系数增大会导致更大的降雨入渗量和土体变形,并延缓地表开始积水的时间。边坡坡度对入渗过程的影响则存在争议,在本研究中,边坡坡度增大,土壤中的降雨入渗量减少,地表流失水增加,有待进一步探索。长远来看,在水力耦合系统中进一步考虑弹塑性耦合法则是更全面了解多孔介质中降雨入渗和地表汇水过程有用的方法。

关键词：非饱和土水力耦合入渗有限元瞬态流动

Free Boundary Problems in the Steel Industry

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工程数学学报 2004年第3期21卷 285-306页

作者： A.D.Fitt J.R.Ockendon C.P.Please School of Mathematics University of SouthamptonHighfieldSouthampton SO17 1BJ UKOCIAMMathematical Institute24-29 St.GilesOxfordOX1 3LBSchool of MathematicsUniversity of SouthamptonHighfieldSouthampton SO17 1BJ UK

This paper considers two novel free boundary problems that emerge from modelling processes basic to steel manufacture. The first process concerns the spray cooling of hot steel sheet during the process of continuous casting. Here, an important practical consideration is the non-monotonicity of the measured heat transfer from the steel as a function of the steel temperature. In order to understand this phenomenon, a two-phase flow model is written down for the heating and vapourisation of the water spray. This model relies on a microscale analysis of droplet vapourisation and, in a steady state, it reduces to a coupled system of nonlinear ordinary differential equations for the spray temperature and water content. This system predicts the conditions for the existence or otherwise of a free boundary separating the two-phase region from a dry vapour layer close to the steel *** thickness of this vapour layer is determined by the solution of a generalised Stefan problem. The second process concerns the macroscopic modelling of pig .iron production in blast furnaces. In the simplest scenario, the blast furnace may be roughly divided into a porous solid region overlaying a hot high pressure gaseous zone. The gas reacts with the solid in a thin "intermediate region" at the base of the solid region and it is in this intermediate region that the pig iron is produced. A free boundary model is proposed for the location of the intermediate region and its stability is investigated.

关键词： free boundary problem mathematical modelling stability

Crack propagation and hydraulic fracturing in different lithologies

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Applied Geophysics 2019年第2期16卷 243-251,255页

作者： Hou Zhen-Kun Cheng Han-Lie Sun Shu-Wei Chen Jun Qi Dian-Qing Liu Zhi-Bo Guangzhou institute of Building Science Co. Ltd.Guangzhou 510440China. LandOcean Energy Services Co. Ltd.Beijing 100084China. School of Energy and Mining Engineering China University of Mining and Technology (Beijing)Beijing 100083China. No.4 Oil Production Plant Huabei Oil Field Ltd.PetroChinaLangfang 065000P.R.China.

We simulated hydraulic fracturing in different lithologic rocks in the horizontal drilling by using the true physical model experiment and large rock specimens, carried out the real-time dynamic monitoring with adding tracer and then did post-fracturing cutting and so on. Based on this monitoring results, we compared and assessed the factors affecting expansion in shale, shell limestone, and tight sandstone and the fracture expansion in these rocks. In shale, the reformed reservoir volume is the highest, fracture network is formed in the process of fracturing. In tight sandstone, the fracture surface boundaries are curved, and the fracture surface area accounts for 25–50% of the entire specimen. In shell limestone, the complexity of the fracture morphology is between shale and tight sandstone, but no fracture network is developed. Brittleness controls the fracture surface area. In highly brittle rocks, the fracture surface area is high. Fracture toughness mainly affects the initiation and propagation of cracks. A fracture network is formed only if bedding planes are present and are more weaker than their corresponding matrix. The horizontal in situ deviatoric stress affects the crack propagation direction, and different lithologies have different horizontal in situ deviatoric stress thresholds. Low f luid injection rate facilitates the formation of complex cracks, whereas high fluid injection rate favors the development of fractures. fluid injection weakly controls the complexity of hydraulic fracturing in low-brittleness rocks, whereas lowviscosity fracturing fluids favor the formation of complex cracks owing to easy enter microcracks and micro-pore. Displacement has a greater impact on high brittle rocks than low brittle rocks.

关键词： shale limestone sandstone:hydraulic fracturing crack propagation rock mechanics