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Progress in Natural Science:Materials International 2004年第3期 55-64页

作者： XIA Jun 1*, HU Guilin 2, fan jianren 2 and CEN Kefa 2(1. college of Computer Science, and Center for engineering and Scientific Computation, zhejiang university. Hangzhou 310027, China 2. Institute for Thermal Power engineering, college of mechanical and energy engineering, zhejiang university. Hangzhou 310027, China) collegeofComputerScience andCenterforEngineeringandScientificComputationZhejiangUniversityHangzhou310027China InstitutetorThermalPowerengineering CollegeofMechanicalandEnergyEngineeringZhejiangUniversityHangzhou310027China

Direct numerical simulation (DNS) has been utilized to solve numerically a two dimensional compressible weak shearing plane jet, in which the jet exit velocity and the co flow velocity are in the same magnitude (2∶1 in this paper). We also use the one way coupling method to simulate the dispersion behaviors of solid particles in various representative sizes, i.e. St =0.01, 1, 10, 100, where St is the Stokes number. We get a vorticity field with fully varicose (symmetrical) modes and the entire precise processes of the rolling up of one spanwise vortex, the pairing of two vortexes and the mixing of three vortexes. The mean longitudinal velocity ( U ) profile compares well against the experimental results. The Reynolds stress profile looks special due to the symmetrical vorticity field. The particles whose St =0.01 reproduce the vortex structures in detail, and the ones of St =1 exhibit interesting self organized behaviors and possess the most non uniform concentration field. They disperse uniformly around the single and pairing vortex kernels, while a few of them are arranged almost in a straight line in the center region of the paring vortexes, which is caused by the contribution of the border of two vortexes in the pairing process. St =10 and 100 can be treated as large particles, on which the flow field has few impacts.

关键词： direct numerical simulation (DNS) plane turbulent jets vortex structures solid particles Stokes number.

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气液两相流体系下微反应器技术研究进展

过程工程学报 2024年第9期24卷 1001-1015页

作者：叶欣然吴赞王海鸥樊建人浙江大学能源工程学院浙江杭州310027 浙江大学电气工程学院浙江杭州310027

微反应器具有传热传质效率高、反应参数控制严格、易于放大、安全性能好等优势。微反应器技术与气液多相催化反应的结合是开发高效且可持续的化工生产技术重要手段。气液多相催化微反应器集成了催化反应和微反应器技术的优点,在化学合... 详细信息

微反应器具有传热传质效率高、反应参数控制严格、易于放大、安全性能好等优势。微反应器技术与气液多相催化反应的结合是开发高效且可持续的化工生产技术重要手段。气液多相催化微反应器集成了催化反应和微反应器技术的优点,在化学合成中具有广泛的应用前景。根据非均相催化剂固定方式,气-液-固三相催化微反应器可以分为壁面负载式微反应器和填充床式微反应器。微反应器中多相流的流动和物质传递都会对微反应器性能产生影响,研究微反应器的气液两相流问题有利于指导高性能微反应器的设计和应用。本工作首先回顾了微反应器技术的特点,介绍了微反应器的结构优化方案,简述了微反应器中的气液两相流流型、传质特点和气泡破裂动力学。随后重点讨论了多相催化微反应器的应用实例以及面临的挑战。最后,结合以往的微反应器研究,对于未来气液两相体系下微反应器技术面临的挑战和发展趋势进行了展望。

关键词：微反应器壁面负载式微反应器填充床式微反应器气液两相流

Predicting impact forces on pipelines from deep-sea fluidized slides:A comprehensive review of key factors

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International Journal of Mining Science and Technology 2024年第2期34卷 211-225页

作者： Xingsen Guo Ning fan Defeng Zheng Cuiwei Fu Hao Wu Yanjun Zhang Xiaolong Song Tingkai Nian State Key Laboratory of Coastal and Offshore engineering Dalian University of TechnologyDalian 116024China Department of Civil Environmentaland Geomatic EngineeringUniversity College LondonLondon WC1E 6BTUnited Kingdom Shandong Provincial Key Laboratory of Marine Environment and Geological engineering Ocean University of ChinaQingdao 266100China State Key Laboratory of Geohazard Prevention and Geoenvironment Protection Chengdu University of TechnologyChengdu 610059China college of Civil engineering and Architecture Wenzhou UniversityWenzhou 325035China Key Laboratory of engineering and Technology for Soft Soil Foundation and Tideland Reclamation of zhejiang Province Wenzhou 325035China zhejiang International Science and Technology Cooperation Base of Ultra-soft Soil engineering and Smart Monitoring Wenzhou 325035China School of Geography Liaoning Normal UniversityDalian 116029China China Railway First Survey and Design Institute Group Co. Ltd.Xi’an 710043China Department of Geotechnical engineering Nanjing Hydraulic Research InstituteNanjing 210024China Wuhan Center China Geological Survey(Central South China Innovation Center for Geosciences)Wuhan 430205China State Key Laboratory of Mining Response and Disaster Prevention and Control in Deep Coal Mines Anhui University of Science and TechnologyHuainan 232001China

Deep-sea pipelines play a pivotal role in seabed mineral resource development,global energy and resource supply provision,network communication,and environmental ***,the placement of these pipelines on the seabed surface exposes them to potential risks arising from the complex deep-sea hydrodynamic and geological environment,particularly submarine *** incidents have highlighted the substantial damage to pipelines due to ***,deep-sea fluidized slides(in a debris/mud flow or turbidity current physical state),characterized by high speed,pose a significant *** assessing the impact forces exerted on pipelines by fluidized submarine slides is crucial for ensuring pipeline *** study aimed to provide a comprehensive overview of recent advancements in understanding pipeline impact forces caused by fluidized deep-sea slides,thereby identifying key factors and corresponding mechanisms that influence pipeline impact *** factors include the velocity,density,and shear behavior of deep-sea fluidized slides,as well as the geometry,stiffness,self-weight,and mechanical model of ***,the interface contact conditions and spatial relations were examined within the context of deep-sea slides and their interactions with *** upon a thorough review of these achievements,future directions were proposed for assessing and characterizing the key factors affecting slide impact loading on pipelines.A comprehensive understanding of these results is essential for the sustainable development of deep-sea pipeline projects associated with seabed resource development and the implementation of disaster prevention measures.

关键词： Deep-sea fluidized slides Pipes Impact forces Shear behavior of slides Interface contact conditions Spatial relation

Biodegradable,strong,and clear wood package for plastic alternative

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Nano Research 2024年第9期17卷 8531-8541页

作者： Jianfu Tang Xueqin fan Haozhou Huang Xiaofei Dong Xueqi Li Peiru Wang Ran Yin Yanjun Xie Jian Li Gang Tan Zhenqian Pang Wentao Gan Key Laboratory of Bio-based Material Science&Technology(Ministry of Education) Northeast Forestry UniversityHarbin 150040China Department of Architecture College of Civil Engineering and ArchitectureZhejiang UniversityHangzhou 310027China Smart Materials for Architecture Research Lab Innovation Center of Yangtze River DeltaZhejiang UniversityJiaxing 314100China Heilongjiang Key Laboratory of Complex Traits and Protein Machines in Organisms Northeast Forestry UniversityHarbin 150040China

Using biodegradable material derived from renewable resources as petroleum-based plastics replacement is a promising way towards sustainable ***,the insufficient mechanical properties and complex manufacturing process of bioplastics still need to be improved for high-quality food ***,we report a top-down strategy to transform natural wood into a clear wood packaging film through scalable delignification and polyvinyl alcohol(PVA)*** wood packaging film demonstrates a laminated structure with completely collapsed cell walls and PVA intertwined together after energy-saving air drying,resulting in high light transmittance with low haze,good mechanical performance,and high barrier performance for oxygen and water *** dynamics simulations reveal the underlying fracture mechanism between cellulose and PVA,which effectively enhances the Young’s modulus and strength of the wood packaging *** findings contribute to the development of biodegradable and strong packaging materials,as well as other food-related applications,using sustainable wood.

关键词： wood food package mechanical enhancement plastic replacement biodegradability

Modulation on flow field by solid particles in gas-solid two-phase turbulent free shear flows

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Progress in Natural Science:Materials International 2003年第3期 21-25页

作者： LUO Kun, fan jianren, JIN Hanhui and CEN Kefa (1. Institute for Thermal Power engineering 2. college of Materials Science and Chemical engineering, zhejiang Unlversity, Hangzhou 310027, China) Institute for Thermal Power engineering college of Materials Science and Chemical engineering Zhejiang University Hangzhou 310027 China

In order to understand the interaction between fluid and particles, a two-way coupled three-dimensional mixing layerladen with particles at a Stokes number of 5 with different mass loadings is numerically studied. The pseudospectral method is used for theflow fluid and the Lagrangian approach is used to trace particles. The concept of computational particles is introduced to vary the massloading of particles. The momentum coupling effect introduced by a particle is approximated to the point force. The simulation resultsshow that the coherent structures are still dominant in the mixing layer, but the flow field is modulated by particles. The addition of theparticles enhances the energy of all the Fourier modes with non-zero spanwise wavenumber, and the enhancement increases with the aug-ment of the mass loading. A higher mass loading results in a lower energy at fundamental wavenumber and streamwise subharmonic Fouri-er mode of the fluid in the phase of Kelvin-Helmholtz rolling up, but for large-scale vo

关键词： direct numerical simulation three-dimensional mixing layer two-way coupling large-scale vortex structures particle dispersion.

分子动力学模拟预测天然气密度和黏度的可行性研究

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化工学报 2024年第2期75卷 450-462页

作者：吴凡彭旭东江锦波孟祥铠梁杨杨浙江工业大学机械工程学院浙江杭州310023

天然气作为相对清洁、低碳的能源,在我国的一次能源消费占比持续增长,其物性的精准预测对天然气集输利用过程分析至关重要。通过收集文献中天然气在不同温度和压力下的物性实测数据,对比分析了分子动力学模拟和常用经验模型计算天然气... 详细信息

天然气作为相对清洁、低碳的能源,在我国的一次能源消费占比持续增长,其物性的精准预测对天然气集输利用过程分析至关重要。通过收集文献中天然气在不同温度和压力下的物性实测数据,对比分析了分子动力学模拟和常用经验模型计算天然气密度和黏度的预测精度,明确了不同组成天然气适用的最佳物性预测模型。结果表明,分子动力学模拟在预测天然气黏度方面具有较强的适用性,尤其是在高温高压条件下,当温度为444.4 K时,平均相对误差小于5%;天然气密度则采用现有相对成熟的经验模型更合适,而采用分子动力学模拟方法的几种力场模型预测其精度均不高;天然气密度和黏度预测模型的预测精度,不仅受温度和压力范围的影响,还与天然气组成有关。

关键词：天然气混合物密度黏度分子模拟

微细波纹板激光热应力成形边界效应的抑制方法

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中国表面工程 2024年第3期37卷 78-88页

作者：姚喆赫范伟鑫陈志敏张群莉姚建华浙江工业大学激光先进制造研究院杭州310023 浙江工业大学特种装备制造与先进加工技术教育部/浙江省重点实验室杭州310023 浙江工业大学机械工程学院杭州310023

激光热应力成形为微细薄板结构的无模制造提供了解决方案,然而其边界效应严重影响成形精度。针对金属薄板激光热应力成形过程中的边界效应,采用振镜式激光,结合有限元模拟和成形试验分析激光工艺参数对边界效应的影响规律。研究了变速... 详细信息

激光热应力成形为微细薄板结构的无模制造提供了解决方案,然而其边界效应严重影响成形精度。针对金属薄板激光热应力成形过程中的边界效应,采用振镜式激光,结合有限元模拟和成形试验分析激光工艺参数对边界效应的影响规律。研究了变速度、变方向以及两者耦合的边界效应抑制策略,进而用于微细波纹板成形过程。结果表明,扫描路径上的温度与应力分布不均是造成边界效应的主要原因,薄板成形过程中的热累积主要存在于扫描结束端,激光工艺参数是影响弯曲成形件变形的重要因素;采用变向-变速耦合策略比单方向扫描的相对角度变化减小77.8%,实现了深宽比大于0.75的微细波纹板精密成形。变向-变速耦合策略能够有效抑制微细波纹板激光热应力成形中的边界效应,为高质量微细薄板成形提供参考。

关键词：激光材料加工波纹板激光热应力成形边界效应抑制策略激光工艺参数

REVERSE MODELING FOR CONIC BLENDING FEATURE

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Chinese Journal of mechanical engineering 2005年第4期18卷 482-489页

作者： fan Shuqian Ke Yinglin college of mechanical and energy engineering Zhejiang University Hangzhou 310027 China

A novel method to extract conic blending feature in reverse engineering is presented. Different from the methods to recover constant and variable radius blends from unorganized points, it contains not only novel segmentation and feature recognition techniques, but also bias corrected technique to capture more reliable distribution of feature parameters along the spine curve. The segmentation depending on point classification separates the points in the conic blend region from the input point cloud. The available feature parameters of the cross-sectional curves are extracted with the processes of slicing point clouds with planes, conic curve fitting, and parameters estimation and compensation, The extracted parameters and its distribution laws are refined according to statistic theory such as regression analysis and hypothesis test. The proposed method can accurately capture the original design intentions and conveniently guide the reverse modeling process. Application examples are presented to verify the high precision and stability of the proposed method.

关键词： Computer-aided design Reverse engineering Feature recognition Geometric modeling Statistic theory Blending surface

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激光热应力成形弯折区形貌演变规律研究

表面技术 2024年第13期53卷 175-186,197页

作者：范伟鑫姚喆赫潘成颢洪锦源刘云峰姚建华浙江工业大学激光先进制造研究院杭州310023 浙江工业大学机械工程学院杭州310023 特种装备制造与先进加工技术教育部/浙江省重点实验室杭州310023

目的针对激光热应力成形弯折区增厚现象,揭示激光热输入、弯曲角度和成形机制对弯曲过程的影响,以及弯折区域形貌的演变规律,为提高激光热应力成形弯折区域的形貌可控性提供参考。方法采用高速相机拍摄成形过程中热输入和弯曲角度对弯... 详细信息

目的针对激光热应力成形弯折区增厚现象,揭示激光热输入、弯曲角度和成形机制对弯曲过程的影响,以及弯折区域形貌的演变规律,为提高激光热应力成形弯折区域的形貌可控性提供参考。方法采用高速相机拍摄成形过程中热输入和弯曲角度对弯折区的宏/微观形貌的作用效果,并采用共聚焦显微镜观察试样的宏观形貌,采用光学显微镜分析微观组织,通过维氏显微硬度计测量弯折区附近材料的硬度分布情况,同时结合温度场数值模拟和表面张力理论分析,揭示弯折区形貌的影响因素及形成机制。结果在低比能作用下,弯折区的熔融材料在激光扫描结束后快速凝固,并在扫描次数逐渐增加的过程中其表面逐渐隆起,并形成凸起状形貌,表面粗糙度随着扫描次数的增加呈现上升趋势,由5.5μm增至37.6μm。在高比能作用下,熔融材料的流动性得到提升,并在表面张力的作用下充分铺展,宏观形貌由凸变平,最后呈现凹形形貌,表面粗糙度随着扫描次数的增加呈现相反的变化趋势,由31.7μm减至5.8μm。此外,在塑性成形过程中,熔池流动仍受到成形角两侧壁面的限制。硬度测试结果表明,激光热应力成形弯折熔凝区域的硬度略高于基体的硬度,热影响区的硬度比基体的硬度降低了40%。结论激光热输入、弯曲角度和成形机制会影响弯折区材料表面的挤压、熔化、流动、凝固过程,以及材料内部的温度梯度和界面表面张力,在这些因素的影响下弯折区域的轮廓形貌、成形粗糙度、显微组织和硬度分布发生了变化。

关键词：激光热应力成形弯折区比能表面张力形貌硬度分布

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