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Effect of Different Raft Shapes on Hydrodynamic Characteristics of the Attenuator-Type Wave Energy Converter

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China Ocean Engineering 2023年第4期37卷 645-659页

作者： wang Jin wang shu-qi JIANG qing-dian XU Yun-xin SHI Wei-chao School of Naval Architecture and Ocean Engineering Jiangsu University of Science and TechnologyZhenjiang 212003China Department of Naval Architecture Ocean and Marine EngineeringUniversity of StrathclydeGlasgowG40LZUK

A numerical simulation method based on CFD has been established to simulate the fully coupled motion for an atten-uator-type wave energy converter(WEC).Based on this method,a detailed parametric analysis has been conducted to investigate the design of the *** effects of different parameters(wave parameters,structural parameters and PTO parameters)on the hydrodynamic characteristics of the attenuator-type WEC were studied in *** results show that in terms of wave parameters,there is an optimal wave period,which makes the relative pitching angle amplitude of the WEC reach the maximum,and the increase of wave height is conducive to the relative pitching angle amplitude of wave *** different wave conditions,the relative pitch angle of the parallelogram raft device is the *** terms of structural parameters,the parallelogram attenuator-type device has the optimal values in different relative directions,different distances and different apex angle,which makes the relative motion amplitude of the device reach the maximum,and the spacing and the apex angle have influence on the motion frequency of the device,while the relative direction has almost no influence on *** terms of PTO parameters,there is an optimal damping coefficient,which makes the power generation efficiency of the WEC reach the *** research results provide a valuable reference for future research and design of the attenuator-type WEC.

关键词： wave energy converter attenuator-type shape hydrodynamic analysis power generation efficiency

Effect of Microstructures on Elevated-Temperature Wear Resistance of a Hot Working Die Steel

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Journal of Iron and Steel Research International 2011年第10期18卷 47-53页

作者： WEI Min-xian wang shu-qi wang Lan CHEN Kang-min School of Materials Science and Engineering Jiangsu University Zhenjiang 212013 Jiangsu China

Elevated-temperature wear tests under atmospheric conditions at 400 ℃ were performed for a hot working die steel H21 on a pin-on-disk wear tester. The phase and morphology of worn surfaces were examined using XRD and SEM, and the relation of wear resistance to tempered microstructures was studied for H21 steel. XRD patterns exhibit that oxidative wear is a predominated wear mechanism with Fe3O4 and Fe2O3 on worn surfaces. It is found that with increasing normal load, obvious plastic deformation of substrate appears on worn surfaces. Microstructures start to affect apparently wear resistance of the steel with an increase of load. Under loads of 50--100 N, wear losses of steel retain low values and relatively approach for steels with various microstructures. As loads are increased to 150--200 N, wear losses of steel start to increase obviously and present apparent difference for steel with various microstructures. Wear resistance is found to increase in the sequence as follows., tempered sorbite, tempered martensite, tempered troostite without secondary hardening and tempered troostite with secondary hardening or upcoming one. Higher strength and microstructural stability are required for steels with excellent wear resistance.

关键词： steel heat treatment microstructure wear wear resistance

Effect of Alloying Elements on Thermal Wear of Cast Hot-Forging Die Steels

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Journal of Iron and Steel Research International 2006年第5期13卷 53-59页

作者： wang shu-qi CHEN Kang-min CUI Xiang-hong JIANG qi-chuan HONG Bian School of Materials Science and Engineering Jiangsu University Zhenjiang 212013 Jiangsu China School of Materials Science and Engineering Jilin University Changchun 130025 Jilin China

The effect of main alloying elements on thermal wear of cast hot-forging die steels was studied. The wear mechanism was discussed. The results show that alloying elements have significant influences on the thermal wear of cast hot-forging die steels. The wear rates decrease with an increase in chromium content from 3% to 4% and molybdenum content from 2% to 3%, respectively. With further increase of chromium and molybdenum contents, chromium slightly reduces the wear resistance and molybdenum severely deteriorates the wear resistance with high wear rate. Lower vanadium/carbon ratio （1.5-2.5） leads to a lower wear resistance with higher wear rate. With an increase in vanadium/carbon ratio, the wear resistance of the cast steel substantially increases. When vanadium/carbon ratio is 3, the wear rate reaches the lowest value. The predominant mechanism of thermal wear of cast hot-forging die steels are oxidation wear and fatigue delamination. The Fe2O3 and Fe3O4 or lumps of brittle wear debris are formed on the wear surface.

关键词： hot-forging die cast steel alloying element thermal wear mechanism

Selection of Heat Treatment Process and Wear Mechanism of High Wear Resistant Cast Hot-Forging Die Steel

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Journal of Iron and Steel Research International 2012年第5期19卷 50-57页

作者： WEI Min-xian wang shu-qi wang Lan CUI Xiang-hong CHEN Kang-min School of Materials Science and Engineering Jiangsu UniversityZhenjiang 212013JiangsuChina

Dry sliding wear tests of a Cr-Mo-V cast hot-forging die steel was carried out within a load range of 50--300 N at 400℃ by a pin-on-disc high temperature wear machine. The effect of heat treatment process on wear resistance was systematically studied in order to select heat treatment processes of the steel with high wear resistance. The morphology, structure and composition were analyzed using scanning electron microscopy （SEM）, X-ray diffraction （XRD） and energy dispersive spectroscopy （EDS） ; wear mechanism was also discussed. Tribo-oxide layer was found to form on worn surfaces to reduce wear under low loads, but appear inside the matrix to increase wear under high loads. The tribo-oxides were mainly consisted of Fe3O4 and Fe2O3, FeO only appeared under a high load. Oxidative mild wear, transition of mild-severe wear in oxidative wear and extrusive wear took turns to operate with increasing the load. The wear resistance strongly depended on the selection of heat treatment processes or microstructures. It was found that bainite presented a better wear resistance than martensite plus bainite duplex structure, martensite structure was of the poorest wear resistance. The wear resistance increased with increasing austenizing temperature in the range of 920 to 1 120 ℃, then decreased at up to 1 220 ℃. As for tempering temperature and microstructure, the wear resistance increased in following order： 700℃ （tempered sorbite）, 200 ℃ （tempered martensite）, 440 to 650 ℃ （tempered troostite）. An appropriate combination of hardness, toughness, microstructural thermal stability was re- quired for a good wear resistance in high-temperature wear. The optimized heat treatment process was suggested for the cast hot-forging steel to be austenized at 1020 to 1 120 ℃, quenched in oil, then tempered at 440 to 650℃ for 2 h.

关键词： cast hot-forging die steel heat treatment process high-temperature wear mechanism wear behavior microstructure

Wear Behavior and Mechanism of Spheroidal Graphite Cast Iron

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Journal of Iron and Steel Research International 2013年第10期20卷 81-86页

作者： YANG Zi-run LI Dong-sheng wang Lan wang shu-qi WEI Min-xian School of Materials Engineering Yancheng Institute of Technology School of Materials Science and Engineering Jiangsu University

Wear behavior and mechanism of spheroidal graphite cast iron were studied on a pin on-disk elevated tem- perature wear tester. The phase and morphology of worn surfaces were examined by X ray diffraction and scanning electron microscopy. Results show that with an increase of load, wear rate of spheroidal graphite cast iron gradually increases under low loads, rapidly increases or potentially increases under high loads; wear rate increases with in- creasing ambient temperature. At 25 200 ℃, adhesive wear prevails; oxidative wear and adhesive wear coexist at 400 ℃. As load surpasses 150 N at 400 ℃, extrusive wear appears. The elevated-temperature wear of spheroidal graphite cast iron is a physical and chemical process including the following reactions： xFe＋y/2O2-FexOy , 2C＋ O2- 2CO and Fex Oy ＋yCO-xFe＋yCO2. Hence, at 400 ℃, the amount of graphite and tribo oxides are substan- tially reduced because of reductive function of graphite. It can be suggested that wear reduced effect of graphite and tribo-oxides is impaired.

关键词： spheroidal graphite cast iron wear behavior wear mechanism tribo oxide microstructure

Geometrical Evaluation on the Viscous Effect of Point-Absorber Wave-Energy Converters

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China Ocean Engineering 2018年第4期32卷 443-452页

作者： CHEN Zhong-fei ZHOU Bin-zhen ZHANG Liang ZHANG Wan-chao wang shu-qi ZANG Jun College of Shipbuilding Engineering Harbin Engineering University School of naval structure and ocean engineering Jiangsu University of Science and Technology Department of Civil and Architecture Engineering University of Bath

The fluid viscosity is known to have a significant effect on the hydrodynamic characteristics which are linked to the power conversion ability of the wave energy converter(WEC). To overcome the disadvantages of case-by-case study through the experiments and numerical computations employed by the former researches, the viscous effect is studied comprehensively for multiple geometries in the present paper. The viscous effect is expressed as the viscous added mass and damping solved by the free-decay method. The computational fluid dynamics(CFD) method is employed for the calculation of the motion and flow field around the floater. The diameter to draft ratio and bottom shape are considered for the geometrical evaluation on the viscous effect. The results show that a slenderer floater presents a stronger viscous effect. Through the comparisons of the floaters with four different bottom shapes, the conical bottom is recommended in terms of low viscous effect and simple geometry for manufacture. A viscous correction formula for a series of cylindrical floaters is put forward, for the first time, to help the engineering design of outer-floaters of point-absorber WECs.

关键词： viscous effect wave energy convertor multiple geometries viscous correction CFD

In Situ Synthesis of Heat Resistant Gradient Composite on Steel Surface

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Journal of Iron and Steel Research International 2009年第2期16卷 89-94页

作者： CUI Xiang-hong wang Feng wang shu-qi YANG Zi-run GAO Ming-juan WEI Min-xian School of Materials Science and Engineering Jiangsu University Zhenjiang 212013 Jiangsu China

A heat resistant gradient composite was synthesized in situ on steel with the self-propagating high temperature synthesis （SHS） reaction of 3Ni-Al-Ti-C system during casting. The phases, microstructure, and composition of the composite were analyzed by using an X-ray diffractometer （XRD）, and a scanning electron microscope （SEM） coupled with an energy-dispersive X-ray spectroscope （EDS）. The formation mechanism of the composite is also discussed. TiC/Ni3 Al/steel gradient composite is achieved by forming the gradient distributions of Fe, Ni, and Al, accompanied with the gradient variation of the microstructure from TiC/Nia A1, to TiC/Ni3 Al/steel, and to steel. The composite is in situ synthesized through whole reaction of 3Ni-Al-Ti-C system in liquid steel and densification procedure, and the liquid steel infiltrates into pores in the SHS product and forces liquid Ni3Al to form self-compaction further.

关键词： steel heat resistant composite synthesis microstructure

Alloying Design for High Wear-Resistant Cast Hot-Forging Die Steels

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Journal of Iron and Steel Research International 2008年第4期15卷 67-72页

作者： CUI Xiang-hong SHAN Jun YANG Zi-run WEI Min-xian wang shu-qi DONG Chuang School of Materials Science and Engineering Jiangsu University Zhenjiang 212013 Jiangsu China Harbin Zhuoyue Information Technology Advance Limited Company Harbin 150001 Heilongjiang China State Key Laboratory of Materials Modification by Laser Ion and Electron Beams Dalian University of Technology Dalian 116024 Liaoning China

The alloying design of cast hot-forging die steels was analyzed. The relationship of the life of cast hot-forging dies with the failure patterns was studied. The thermal wear resistance was believed to be the key property for the alloying design of cast hot-forging die steels. The alloying design parameters were selected and optimized for the cast hot-forging die steel with high wear resistance. The wear resistance of the optimized cast die steel was evaluated in comparison with commercial H13 steels and 3Cr2WSV steel. In the new cast hot-forging die steel, VC is predominant carbide with Cr and Mo as the main solution elements in α-Fe. It is found that the cast die steel has significantly lower wear rate than normal H13 steel and 3Cr2W8V steel, almost the same as that of high purity H13 steel. The high wear resistance of the new cast hot-forging die steel can be attributed to its reasonable alloying design and nonsensibility to the detrimental function of S and P.

关键词： hot-forging die cast steel wear resistance alloying design

Scapaundulin C,a novel labdane diterpenoid isolated from Chinese liverwort Scapania undulate,inhibits acetylcholinesterase activity

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Chinese Journal of Natural Medicines 2015年第12期13卷 933-936页

作者： KANG Ya-qi ZHOU Jin-Chuan FAN Pei-Hong wang shu-qi LOU Hong-Xiang Department of Natural Products Chemistry School of Pharmaceutical SciencesShandong University

In the present study, scapaundulin C(1), a new labdane diterpenoid, and four related known compounds scapaundulin A(2), 5?, 8?, 9?-trihydroxy-13E-labden-12-one(3), 5?, 8?-dihydroxy-13E-labden-12-one(4), and(13S)-15-hydroxylabd-8(17)-en-19-oic acid(5), were isolated from the Chinese liverwort Scapania undulate(L.) Dum., using column chromatography. The structures of these compounds were determined on the basis of 1D- and 2D-NMR analyses. The acetylcholinesterase(Ach E) inhibitory activity was evaluated using a bioautographic TLC assay and the cytotoxic activity was evaluated by the MTT method. All the compounds were reported for the first time to exhibit moderate Ach E inhibitory activity with minimal inhibitory quantities ranging from 250 to 500 ng. All the compounds were tested for their cytotoxicity against five human tumor cell lines, A549, K562, A2780, Hela, and HT29, and compounds 3 and 4 exhibited moderate inhibitory effects on the growth of A2780 cells.

关键词： Liverwort Scapania undulate Labdane diterpenoid AChE inhibitory activity Cytotoxic activity