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Chinese Journal of Chemical Engineering 2018年第12期26卷 2431-2440页

作者： Yongliang Wan Runhan Wu Cong Qi Gang Duan Ruizhao Yang Automotive Engineering Research Institute Shaanxi Heavy Automobile Co.LtdXfan 710200China School of Electrical and Power Engineering China University of Mining and Technology Xuzhou 221116China

Thermo-hydraulic characteristics of TiO_2-water nanofluids in thin-wall stainless steel test tubes(corrugated tube and circular tube) filled with copper foam(40 PPI) are experimentally investigated and compared with those in test tubes without copper foam. The effects of nanoparticle mass concentration on flow and heat transfer performances are investigated. In addition, the mutual restriction relationships between Reynolds number(Re), Nusselt number(Nu) and resistance coefficient(f) are discussed respectively. Also, the comprehensive coefficient of performance(CCP) between heat transfer and pressure drop is evaluated. The results show that core-enhancement region for heat transfer using experimental tubes filled with copper foam is notably different from that of tubes without copper foam. There is a corresponding Reynolds number(about Re = 2400) for the maximum CCP of each condition. And the heat transfer can be enhanced dramatically and sustained at 8000 ≤ Re ≤ 12000.

关键词： Nanofluids Heat transfer enhancement Nanoparticle Corrugated tube

Springback prediction of thick-walled high-strength titanium tube bending

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Chinese Journal of Aeronautics 2013年第5期26卷 1336-1345页

作者： Song Feifei Yang He Li Heng Zhan Mei Li Guangjun State Key Laboratory of Solidifcation Processing School of Materials Science and EngineeringNorthwestern Polytechnical University Chengdu Aircraft Industry (Group) Corporation Ltd.

Significant springback occurs after tube rotary-draw-bending （RDB）, especially for a high-strength Ti-3A1-2.5V tube （HSTT） due to its high ratio of yield strength to Young＇s modulus. The combination scheme of explicit and implicit is preferred to predict the springback. This simulation strategy includes several numerical parameters, such as element type, number of elements through thickness （NEL）, element size, etc. However, the influences of these parameters on spring- back prediction accuracy are not fully understood. Thus, taking the geometrical specification 9.525 mm × 0.508 mm ofa HSTT as the objective, the effects of numerical parameters on prediction accuracy and computation efficiency of springback simulation of HSTT RDB are investigated. The simulated springback results are compared with experimental ones. The main results are：（1） solid and continuum-shell elements predict the experimental results well; （2） for C3DSR elements, NEL of at least 3 is required to obtain reliable results and a relative error of 29% can occur as NEL is varied in the range of 1-3; （3） specifying damping factor typically works well in Abaqus/Emplicit simulation of springback and the springback results are sensitive to the magnitude of damping factor. In addition, the explanations of the effect rules are given and a guideline is added.

关键词： Bending Finite element method High strength Numerical parameters Solid elements Springback Titanium alloys tube

Microstructure evolution of a recycled Al-Fe-Si-Cu alloy processed by tube channel pressing

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International Journal of Minerals,Metallurgy and Materials 2018年第10期25卷 1166-1172页

作者： M.H.Farshidi M.Rifai H.Miyamoto Department of Materials Science and Metallurgical Engineering Ferdowsi University of Mashhad Department of Mechanical Engineering Doshisha University

Although excellent recyclability is one of the advantages of Al alloys, a recycling process can reduce different properties of these alloys by adding coarse AlFeSi particles into the alloys' microstructures. One of the well-known methods for modifying the microstructure of metallic materials is the imposition of severe plastic deformation(SPD). Nevertheless, the microstructure evolutions of recycled Al alloys containing extraordinary fractions of AlFeSi particles during SPD processing have seldom been considered. The aim of the present work is to study the microstructure evolution of a recycled Al–Fe–Si–Cu alloy during SPD processing. For this purpose, tubular specimens of the mentioned alloy were subjected to different numbers of passes of a recently developed SPD process called tube channel pressing(TCP); their microstructures were then studied using different techniques. The results show that coarse AlFeSi particles are fragmented into finer particles after processing by TCP. However, decomposition and dissolution of AlFeSi particles through TCP processing are negligible. In addition, TCP processing results in an increase in hardness of the alloy, which is attributed to the refinement of grains, to an increase of the dislocation density, and to the fragmentation of AlFeSi particles.

关键词： AlFeSi intermetallic particle severe plastic deformation microstructure tube channel pressing

Hybrid reinforced thermoset polymer composite in energy absorption tube application:A review

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Defence Technology（防务技术） 2018年第4期14卷 291-305页

作者： A.B.M.Supian S.M.Sapuan M.Y.M.Zuhri E.S.Zainudin H.H.Ya Department of Mechanical and Manufacturing Engineering Universiti Putra Malaysia Laboratory of Bio Composite Technology Institute of Tropical Forestry and Research Products (INTROP)Universiti Putra Malaysia Department of Mechanical Engineering Universiti Teknologi Petronas

The custom of hybridization fibre composite in energy absorption tube application has gained the attention of structural crashworthiness in composite material industry. Thus, the approach of this review is to understand the effect in hybridization within metal/synthetic fibre composite, synthetic/synthetic fibre composite and nature/synthetic fibre composite as energy absorption tube, which reflects on the energy absorption characteristics and crashworthiness behaviors in previous the study. By way of instance, a wide range of methodology and particular parameter in previous study such as the effect in fibre arrangement, matrix polymer, technique of fabrication, fibre treatment(natural fibre), design in geometry/cross-section and others mechanism of hybrid fibre composite tube are highlighted which to comprehend the capability of the mechanical performance and collapsible behavior as sacrificial structure in high-performance structure applications. Moreover, in the recently studies there have been many of the research regarding structural materials as energy absorption tube has been introduced such as metal/matrix composites, new alloy metals and polymer composites which intended to evaluate the performance of these materials into circumstance in loading and impact characteristic. Therefore, this review article is trying to explore the research articles related to the effect of hybridization fibres and thermoset polymer as reinforcement for energy absorption tube research and expected would provide an information and idea which to expend the knowledge in future study of hybridization effect for energy absorption tube, moreover the development for future potential as new hybrid composite fibre materials from the natural/synthetic fibres reinforced composite material in employing of high-performance energy absorption tube application is still less discover and highlighted.

关键词： Energy absorption tube Hybrid composites Collapse behavior Crashworthiness

Influences of the inner diameter of the solid shielding tube on the characteristics of the radio-frequency cold atmospheric plasma jet

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Plasma Science and Technology 2019年第9期21卷 82-90页

作者： Jing LI Heping LI Department of Engineering Physics Tsinghua University

Active control of the local environment of the cold atmospheric plasma(CAP) jet is of great importance in actual applications since the CAP operates in an open atmosphere with the inevitable entrainment of the surrounding cold air. In this paper, the solid shielding effects of the cylindrical quartz tubes with different inner diameters on the characteristics of the CAP jets driven by a radio-frequency(RF) power supply are studied experimentally. The experimental results show that the total length of the shielded plasma jet can be increased significantly by an appropriate combination of the quartz tube inner diameter and that of the plasma generator nozzle exit with other parameters being unchanged. This phenomenon may be qualitatively attributed to the loss of diffusion of the charged particles in the radial direction under different inner diameters of the quartz tubes. Compared with the plasma free jet, the plasma shielding jet is produced with optimized parameters including longer plasma jet length, higher concentrations of chemically reactive species, higher rotational, vibrational, and electron excitation temperatures when the inner diameters of the solid shielding tube and the generator nozzle exit are the same. A maximum plasma jet length of 52.0 cm is obtained in contrast to that of 5.0 cm of the plasma free jet in this study. The experimental results indicate that the solid shielding effect provides a new method for the active control of the local environment of the RF-CAP jet operating in an open atmosphere.

关键词： cold atmospheric plasma jet radio-frequency glow discharge solid shielding effect effect of the tube inner diameter active control of plasma jet characteristics

Effect of process parameters on steel tube roundness in straightening process

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Journal of Iron and Steel Research International 2020年第11期27卷 1270-1283页

作者： Li-dong Ma Yu-kang Du Zhi-juan Meng Li-feng Ma Zi-jian Liu Pei-yu Liu Coordinative Innovation Center of Taiyuan Heavy Machinery Equipment Taiyuan University of Science and TechnologyTaiyuan 030024ShanxiChina School of Mechanical Engineering Taiyuan University of Science and TechnologyTaiyuan 030024ShanxiChina School of Materials Science and Engineering Taiyuan University of Science and TechnologyTaiyuan 030024ShanxiChina School of Applied Science Taiyuan University of Science and TechnologyTaiyuan 030024ShanxiChina

The inclined six-roll tube straightener is an important equipment for the finishing *** can not only straighten the steel pipe,but also finish the ovality of the cross *** the actual straightening process,the cross section of the tube is prone to deform,that is,the round ness is not *** flatteni ng displacement is an import a nt parameter to control cross-section forming of *** to the established mechanical model,the analytical calculation equations of the flattening force and the flattening displacement were derived using the energy *** on the finite element simulation data,the ratios of the finite element results of the什attening force to the analytical ones were *** correlation coefficient after fitting is greater than 99%,and the fitting effect is *** flattening experiment was carried out on tubes of different materials and different specifications,and the setting method of the optimal flattening displacement during straightening process was *** the actual straightening process,using this flattening displacement,the ovality of straightened steel tube is less than 0.3%.Therefore,the proposed method can provide a reference for the flattening displacement in the actual straightening process.

关键词： Straightening tube Energy method Flattening force Flattening displacement Finite element method

Route Effect on Equal Channel Angular Pressing of Copper tube

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Acta Metallurgica Sinica(English Letters) 2014年第1期27卷 95-100页

作者： Faramarz Djavanroodi Ali Asghar Zolfaghari Mahmoud Ebrahimi Kamran Nikbin Department of Mechanical Engineering Imperial College Mechanical Engineering Department Iran University of Science and Technology

A new technique to produce ultra-fine grained tubular specimen has been proposed, and the experiments have been performed using equal channel angular pressing （ECAP） with an angle of 90 between two intersecting channels and also the use of rubber pad as a mandrel during process. Commercial purity copper tubes have been pressed up to three passes through four different fundamental routes （A, BA, Bc, and C） directions of which are identified in the text below. The influence of each route on the value, distribution, and homogeneity of hardness has been investigated by applying Vickers micro-hardness measurements at various locations of the tube＇s transverse planes. Significant enhancement of the hardness is observed after the first pass ECAP. Also, routes C and Bc show, respectively, better average hardness magnitude and hardness distribution uniformity. In addition, the results indicate that there is about 50% and 62% reduction of the grain size, compared to the annealed condition, following ECAP process of the copper tube sample after the first and the third pass via route Bc.

关键词： Severe plastic deformation (SPD) Equal channel angular pressing (ECAP) tube Route Hardness

Porous hollow carbon tube derived from kapok fibres as efficient metal-free oxygen reduction catalysts

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Science China(Technological Sciences) 2019年第10期62卷 1710-1718页

作者： TANG JiaHuan WANG YaJun ZHAO WenQi YE Wen Yuan ZHOU ShunGui Fujian Provincial Key Laboratory of Soil Environmental Health and Regulation College of Resources and EnvironmentFujian Agriculture and Forestry University

Pyrogenic biomass carbon has been deemed a promising alternative to Pt/C for the oxygen reduction reaction(ORR) owing to its low cost, excellent activity, and eco-friendly properties. Herein, a porous carbon tube material derived from kapok fibres was prepared by combining activation with pyrolysis. Electrochemical measurements demonstrated that the kapok fibre-derived material prepared at 900°C had excellent ORR performance with a half-wave potential –0.14 V(vs. Ag/Ag Cl) close to that of commercial Pt/C(–0.13 V vs. Ag/Ag Cl) in 0.1 mol L–1 KOH. The prepared material also displayed remarkable methanol tolerance and durability. Furthermore, the maximum power density output of the microbial fuel cell using the prepared material was(801±40) mW m–2, comparable to that of the Pt/C cathode((778±31) mW m–2). The present work provides a facile way of using economical and renewable biomass to develop a porous structure and high-activity cathode ORR catalyst for fuel cell applications.

关键词： kapok fibre porous carbon tube oxygen reduction reaction microbial fuel cell

NUMERICAL SIMULATION OF THE tube EROSION RESULTED FROM PARTICLES IMPACTS

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Chinese Journal of Chemical Engineering 1997年第4期5卷 55-64页

作者：樊建人陈丽华张新育岑可法 Department of Energy Engineering Zhejiang University

In this paper,a tube erosion caused by the turbulent flow of a dilute particle-laden gas isstudied *** equations are used to describe the gas-phase motion with the turbulenceviscosity evaluated from a k-ε model of *** effect of the turbulence with a stochasticdispersion model has been taken into account for the prediction of impact particle velocity and itstrajectory,The particle impact and rebound model and the erosion model of ductile alloys obtainedby Tabakoff et *** used to predict the particle rebound phenomena and the erosion suffered bythe *** results obtained in this study include the distributions of particle collision frequencyand erosion of tube surface.

关键词： tube erosion particle impact numerical simulation

Response features of nonlinear circumferential guided wave on early damage in inner layer of a composite circular tube

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Chinese Physics B 2019年第4期28卷 224-229页

作者： Ming-Liang Li Liang-Bing Liu Guang-Jian Gao Ming-Xi Deng Ning Hu Yan-Xun Xiang Wu-Jun Zhu College of Aerospace Engineering Chongqing University School of Mechanical and Power Engineering East China University of Science and Technology

A theoretical model to analyze the nonlinear circumferential guided wave(CGW) propagation in a composite circular tube(CCT) is established. The response features of nonlinear CGWs to early damage [denoted by variations in third-order elastic constants(TOECs)] in an inner layer of CCT are investigated. On the basis of the modal expansion approach, the second-harmonic field of primary CGW propagation can be assumed to be a linear sum of a series of double-frequency CGW(DFCGW) modes. The quantitative relationship of DFCGW mode versus the relative changes in the inner layer TOECs is then investigated. It is found that the changes in the inner layer TOECs of CCT will obviously affect the driving source of DFCGW mode and its modal expansion coefficient, which is intrinsically able to influence the efficiency of cumulative second-harmonic generation(SHG) by primary CGW propagation. Theoretical analyses and numerical simulations demonstrate that the second harmonic of primary CGW is monotonic and very sensitive to the changes in the inner layer TOECs of CCT, while the linear properties of primary CGW propagation almost remain unchanged. Our results provide a potential application for accurately characterizing the level of early damage in the inner layer of CCT through the efficiency of cumulative SHG by primary CGW propagation.

关键词： circumferential guided wave(CGW) early damage inner layer of composite circular tube secondharmonic generation(SHG)