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Friction 2024年第2期12卷 305-318页

作者： Yangyang ZHAO guoyuan zhang Junqian WANG He WANG Weigang ZHAO Qunfeng ZENG School of Mechano-Electronic Engineering Xidian UniversityXi’an 710071China Xi’an Aerospace Propulsion Institute Xi’an 710071China Key Laboratory of Education Ministry for Modern Design and Rotor-Bearing System Xi’an Jiaotong UniversityXi’an 710049China

The friction coefficient and wear rate of pretreated graphite with liquid nitrogen were obtained by using a ball-on-disk tester,and the wear of GCr15–graphite seal pairs with the low-temperature time-dependent pretreatment was discussed by comparing the wear *** results show that liquid nitrogen pretreatment can affect the hardness and interlayer spacing of *** range of the friction coefficients of pretreated graphite changes from 0.17 to *** the increase of liquid nitrogen pretreatment time,the wear mechanism of graphite would change from dominated three-body wear to adhesion *** experimental results of the mechanical seal with liquid nitrogen pretreatment show that the wear rate of stator is less than 0.00165 mm^(3)·N^(−1)·m^(−1),and the graphite shows a good low-temperature compatibility.

关键词： graphite low-temperature pretreatment mechanical seal friction and wear

四自由度串联嫁接机器人架构约束模块识别可视化方法

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中国农机化学报 2024年第6期45卷 191-200页

作者：张国渊王豪李栋廉佳汝闫超西安电子科技大学机电工程学院西安市710071

为实现育苗嫁接的智能化与高效化,一类四自由度串联嫁接机器人的新结构被提出;针对其机械结构、时序控制、联动运行等复杂性,发展该类机器人架构约束下的模块识别可视化方法及设计流程。首先,构建考虑特定架构约束下机器人的设计结构矩... 详细信息

为实现育苗嫁接的智能化与高效化,一类四自由度串联嫁接机器人的新结构被提出;针对其机械结构、时序控制、联动运行等复杂性,发展该类机器人架构约束下的模块识别可视化方法及设计流程。首先,构建考虑特定架构约束下机器人的设计结构矩阵(DSM),并采用大型社区快速展开算法(LOUVAIN算法)实现对机器人架构模块的预划分;其次,采用改进遗传算法(AGA)对DSM进行聚类,获得多组高模块度的划分结果,由此形成成组可能性矩阵(GLM),并将其对角化得到对角GLM(DGLM);最后,提出针对DGLM的可视化策略并完成着色处理,实现对最优模块划分方案的辨识。结果显示:四自由度串联嫁接机器人可分解为较独立的7大模块,模块度可达0.782。

关键词：嫁接机器人模块化设计架构约束遗传算法

涡轮动力模拟器甩油盘热流模型与流场特性研究

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机电工程 2024年第7期41卷 1285-1292,1308页

作者：吴福章段雪峰刘砚黎旭康张国渊中国空气动力研究与发展中心四川绵阳621000 西安电子科技大学机电工程学院陕西西安710071

甩油盘作为涡轮动力模拟器(TPS)的重要零件,能有效地促进模拟器内循环系统润滑油的回流,提高轴承的润滑性并降低系统温升,为整机安全可靠运行提供了基础性保障。为了解决TPS内循环系统润滑油的回流问题,对TPS甩油盘及其内部循环流道进... 详细信息

甩油盘作为涡轮动力模拟器(TPS)的重要零件,能有效地促进模拟器内循环系统润滑油的回流,提高轴承的润滑性并降低系统温升,为整机安全可靠运行提供了基础性保障。为了解决TPS内循环系统润滑油的回流问题,对TPS甩油盘及其内部循环流道进行了研究。首先,确定了涡轮动力模拟器轴承发热量及散热系数随转速的变化、甩油盘内部流体控制方程和边界条件;然后,构建了一类TPS甩油盘及其内部循环流道的完整内循环热流模型,并对比了轴承处温度仿真结果与实验结果以确保模型的合理性;最后,数值仿真得到了不同转速下内部循环流道的温度场、压力场和速度场。研究结果表明:转速增加能显著引发系统内最高温度上升,甩油盘作用下的内循环流场温度变化较为平稳,典型工况条件下仿真与实验得到的最高温度相对误差最大为12.3%,表明了热流模型的合理性。研究结果对于指导TPS甩油盘结构设计和提高整机运行安全稳定性具有重要的价值。

关键词：涡轮动力模拟器甩油盘热流模型流场特性温度场

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Friction and wear behavior of different seal materials under water-lubricated conditions

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Friction 2021年第4期9卷 697-709页

作者： Weigang ZHAO guoyuan zhang Guangneng DONG School of Astronautics Northwestern Polytechnical UniversityXi’an 710072China School of Mechano-Electronic Engineering Xidian UniversityXi'an 710071China Key Laboratory of Modern Design and Rotor-bearing System of Ministry of Education Xi’an Jiaotong UniversityXi’an 710049China

The shaft mechanical face seal in a high-speed turbopump of a liquid rocket engine often operates under extremely harsh *** example,a low-temperature and low-viscosity fluid(such as liquid oxygen or liquid hydrogen)is used as a *** performance of the seal rings,especially the friction and wear behavior,directly determines whether the seal functions *** this study,the friction and wear behavior of several ring materials are tested using a pin-on-disk tribo-tester,and the wear morphology of the ring is *** friction coefficients(COFs)and mass-wear rates under dry-friction and water-lubricated conditions,which are used to simulate low-viscosity conditions,are *** results show that at a pressure-velocity(PV)value of 2.4 MPa-(m/s),the COF between the copper graphite(stator)and copper-chrome alloy disk(rotor)is low(with a value of 0.18)under the dry-friction conditions,and the 5-min wear mass of the copper graphite is approximately 2 *** the water-lubricated conditions,compared with other materials(such as copper-chrome alloy,S07 steel,alumina ceramic coating,and nickel-based calcium fluoride),the S07 steel with a diamond-like carbon film is preferred for use in a high-speed turbopump under extreme *** results of this study can provide theoretical and experimental guidance in the design of mechanical face seals in liquid rocket engines.

关键词： friction wear mechanical face seal water-lubricated high-speed turbopump

Dietary supplementation of laminarin improves the reproductive performance of sows and the growth of suckling piglets

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Journal of Animal Science and Biotechnology 2024年第1期15卷 329-343页

作者： Pengguang zhang guoyuan Jiang Chenghong Ma Yubo Wang Enfa Yan Linjuan He Jianxin Guo Xin zhang Jingdong Yin State Key Laboratory of Animal Nutrition and Feeding College of Animal Science and TechnologyChina Agricultural UniversityBeijing 100193China

Background Maternal nutrition is essential in keeping a highly efficient production system in the pig *** has been shown to improve antioxidant capacity,reduce the inflammatory response,and favor the homeostasis of intestinal ***,the effect of dietary supplementation of laminarin on the reproductive performance of sows and the growth of suckling offspring remains *** A total of 40 Landrace×Yorkshire multiparous sows on d 85 of gestation,similar in age,body weight(BW),parity and reproductive performance,were randomly divided into four dietary treatments with 10 sows per treatment,receiving a control diet(basal pregnancy or lactating diets)and a basal diet supplemented with 0.025%,0.05%and 0.10%laminarin,*** experiment lasted from d 85 of gestation to d 21 of *** Laminarin supplementation linearly increased number born alive per litter(P=0.03),average daily feed intake(ADFI,P<0.01),and total milk yield of sows during the lactation of 1–21 d(P=0.02).Furthermore,maternal laminarin supplementation increased the average daily gain(ADG)of piglets while tending to reduce the culling and death rate before *** addition,alterations to the composition of colostrum and milk,as well as to serum inflammatory cytokines and immunoglobulins of sows were *** fecal microbiota profile of sows supported the improvement of reproductive performance in sows and the growth performance in suckling *** Dietary supplementation of laminarin during late pregnancy and lactation could significantly improve reproductive performance of sows and growth performance of piglets.

关键词： Fecal microbiota Laminarin Milk Piglets Reproductive performance Sows

Dry Friction and Wear Characteristics of Impregnated Graphite in a Corrosive Environment

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Chinese Journal of Mechanical Engineering 2014年第5期27卷 965-971页

作者： JIA Qian YUAN Xiaoyang zhang guoyuan DONG Guangneng ZHAO Weigang Key Laboratory of Education Ministry for Modem Design and Rotor-bearing System Xi'an Jiaotong University School of Electromechanical Engineering Xidian University Xi'an Aerospace Propulsion Institute China Aerospace Science and Technology Corporation

Tribological properties of impregnated graphite are greatly influenced by preparation technology and working conditions and it’s highly susceptible to corrosion environmental impacts,but the experimental research about it are *** this paper,three kinds of impregnated graphite samples are prepared with different degree of graphitization,the tribological properties of these samples in the dry friction environment and in a corrosive environment are analyzed and *** tribo-test results show that the friction coefficient of samples is reduced and the amount of wear of samples increase when the graphitization degree of samples increases in dry friction *** in a corrosive environment（samples are soaked N2O4）,the friction coefficient and amount of wear are changed little if the graphitization degree of samples are *** the degree of graphitization increase,the friction coefficient and amount of wear of samples increase too,the amount of wear is 2 to 3 times as the samples tested in the non-corrosive environment under pv value of 30MPa？m/*** impregnated graphite,which friction coefficient is stable and graphitization degree is in mid level,such#2,is more appropriate to have a work in the corrosion *** this paper,preparation and tribological properties especially in corrosive environment of the impregnated graphite is studied,the research conclusion can provide an experimental and theoretical basis for the selection and process improvement of graphite materials,and also provide some important design parameters for contact seal works in a corrosive environment.

关键词： corrosive environment impregnated graphite graphitization dry friction coefficient of friction amount of wear

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不对中齿轮联轴器-轴承-转子系统动力特性

航空动力学报 2022年第2期37卷 225-234页

作者：张国渊梁茂檀郭进兴牛晓辙西安电子科技大学机电工程学院西安710071 中国航天科技集团有限公司西安航天动力研究所西安710100

为适应液体火箭发动机高速涡轮泵模拟运转需求,内啮合齿轮联轴器被设计作为涡轮快速起动过程运动传递的核心零部件;实际中联轴器前后两轴的不对中程度对试验转子动态性能产生了极大影响。构建了此类特定工程应用的内啮合齿轮联轴器刚度... 详细信息

为适应液体火箭发动机高速涡轮泵模拟运转需求,内啮合齿轮联轴器被设计作为涡轮快速起动过程运动传递的核心零部件;实际中联轴器前后两轴的不对中程度对试验转子动态性能产生了极大影响。构建了此类特定工程应用的内啮合齿轮联轴器刚度阻尼计算模型、多种不对中工况的表征方法及其附加力与力矩的求解模型、考虑不对中因素的联轴器-滚动轴承-双转子动力学分析模型,耦合上述模型数值求解得到了不对中参数对试验转子动力学性能的影响规律,包括临界转速、振动响应等,与文献对比完成了模型验证。结果表明:构建模型的动态响应误差小于15%;缩短联轴器和提高涡轮和试验转子同轴对中量可较好地降低系统的动力响应值,可有效地降低转子碰磨故障现象的产生,且其对双转子系统临界转速的影响较小,研究将为高速涡轮泵的设计和安全运行提供理论和试验参考。

关键词：齿轮联轴器不对中转子动力学临界转速振动响应

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TPS甩油盘端面槽型优化及创新设计

航空动力学报 2023年第8期38卷 1846-1856页

作者：黎旭康张国渊吴福章梁茂檀西安电子科技大学机电工程学院西安710071 中国空气动力研究与发展中心四川绵阳621000

针对涡轮动力仿真器现有的端面半圆线槽型甩油盘未能实现对内部循环流场的散热和润滑最大效能的问题,开展以降低最大流场温度和减弱涡流效应的槽型优化研究。提出了包括拋物线、渐开线、对数螺旋线等槽型新结构,并探讨了槽深、槽数、螺... 详细信息

针对涡轮动力仿真器现有的端面半圆线槽型甩油盘未能实现对内部循环流场的散热和润滑最大效能的问题,开展以降低最大流场温度和减弱涡流效应的槽型优化研究。提出了包括拋物线、渐开线、对数螺旋线等槽型新结构,并探讨了槽深、槽数、螺旋角系数等单一因素对流场特性的影响规律,采用正交试验法对多因素多目标的槽型结构参数进行了优化。结果表明:对数螺旋线槽型为一类更能提高润滑和散热的最优结构,利用正交试验法优化出的一组最优对数螺旋线槽型参数槽深为6 mm、槽数为10、螺旋角系数为0.4,以此设计了面向更高工况条件下的新型甩油盘结构,并仿真分析了其在典型工况下的流场特性。

关键词： TPS甩油盘端面槽型优化流场特性多目标优化正交试验法

The intensity ratio I (557.7 nm)/I (427.8 nm) at Zhongshan Station in Antarctica

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Advances in Polar Science 2012年第1期23卷 9-11页

作者： HU guoyuan AI Yong zhang Hong Wuhan University Wuhan 430070 China

Auroral intensity ratios at Zhongshan Station in Antarctica on 8 April 1999 are studied, along with variations in pene- trated electron energy. Ratios of/（557.7 nm）/I （427.8 nm） during the quiet period were from 5 to 22, and I （630.0 nm） / I （427.8 rim） ranged from 1 to 2.76. These variations were not caused by changes of atomic oxygen concentration, but rather by penetrated electron energy variability, or other mechanisms. Ratios decreased sharply during the auroral substorm, ranging from 1.66--6.5 and 0.071-1, respectively, mainly because of the increase in penetrated electron energy. At the onset of the substorm, the ratios reached their minima. This means that penetrated electron energy was maximized. When the substorm weakened, the penetrated electron energy returned to the pre-substorm level.

关键词： Auroral substorm intensity ratio electron

低温高速动静结合型机械密封两相流仿真与实验

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航空学报 2023年第23期44卷 201-213页

作者：张国渊黎旭康赵伟刚赵洋洋王俊倩西安电子科技大学机电工程学院西安710071 西安航天动力研究所西安710100

液体火箭发动机高速涡轮泵轴端动静结合型机械密封端面液膜受低温、高速、高压等极端工况影响极易产生气液两相流现象;诱发两相流的机制及相变对密封的影响规律尚不明确,亟需发展相关的仿真模型并开展实验验证工作。以某高速涡轮泵用动... 详细信息

液体火箭发动机高速涡轮泵轴端动静结合型机械密封端面液膜受低温、高速、高压等极端工况影响极易产生气液两相流现象;诱发两相流的机制及相变对密封的影响规律尚不明确,亟需发展相关的仿真模型并开展实验验证工作。以某高速涡轮泵用动静结合型螺旋槽机械密封为研究对象,基于Laminar层流及Mixture多相流模型,开展了低温、高速等极端工况下密封间隙内流体的空化相变特性研究;以泄漏量、开启力与内部气相体积占比等性能参数为表征指标,分析了该类密封在液氮介质环境工况参数对两相流动特性和相态转变的影响规律。结果表明随着密封间隙增加将导致两相流在有限约束范围内的体积增大,较弱的动压效应导致内部压力产生较小变化进而使得空化相变能力减小;气相体积占比随着液膜温度的增加而增大,随着密封介质压力的增加而减小。开展了低温实验研究,并验证了仿真模型的正确性,理论与实验结果将有助于深入理解低温高速动静结合型机械密封两相流机理,对可重复高速涡轮泵的运行可靠性和稳定性提升具有重要的实践价值。

关键词：动静结合型机械密封两相流空化相变密封性能低温实验