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学者姓名：张优云
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Abstract ：
Currently, many studies on the local discontinuous Galerkin method focus on the Cartesian grid with low computational efficiency and poor adaptability to complex shapes. A new immersed boundary method is presented, and this method employs the adaptive Cartesian grid to improve the adaptability to complex shapes and the immersed boundary to increase computational efficiency. The new immersed boundary method employs different boundary cells (the physical cell and ghost cell) to impose the boundary condition and the reconstruction algorithm of the ghost cell is the key for this method. The classical model elliptic equation is used to test the method. This method is tested and analyzed from the viewpoints of boundary cell type, error distribution and accuracy. The numerical result shows that the presented method has low error and a good rate of the convergence and works well in complex geometries. The method has good prospect for practical application research of the numerical calculation research.
Keyword ：
Adaptive Cartesian grid Heat transfer equation Immersed boundary method Local discontinuous Galerkin method Reconstruction
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| GB/T 7714 | Zhang, Xu-Jiu , Zhu, Yong-Sheng , Yan, Ke et al. New Immersed Boundary Method on the Adaptive Cartesian Grid Applied to the Local Discontinuous Galerkin Method [J]. | CHINESE JOURNAL OF MECHANICAL ENGINEERING , 2018 , 31 (1) . |
| MLA | Zhang, Xu-Jiu et al. "New Immersed Boundary Method on the Adaptive Cartesian Grid Applied to the Local Discontinuous Galerkin Method" . | CHINESE JOURNAL OF MECHANICAL ENGINEERING 31 . 1 (2018) . |
| APA | Zhang, Xu-Jiu , Zhu, Yong-Sheng , Yan, Ke , Zhang, You-Yun . New Immersed Boundary Method on the Adaptive Cartesian Grid Applied to the Local Discontinuous Galerkin Method . | CHINESE JOURNAL OF MECHANICAL ENGINEERING , 2018 , 31 (1) . |
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Abstract ：
In condition of high rotation speed, air vortexes and high pressure air blocks will be induced by the enhanced air flow inside the rolling bearing cavity, which will have strong effect on the oil-air transportation and lubrication performance of the ball bearings. For angular contact ball bearing at ultra high speed (dmn≥2.0×106mm·r·min-1), the air flow pattern is investigated in consideration of structure characteristics, contact feature and motion boundary. The rotating coordinate system is employed to denote bearing subassembly motions thus a high precise numerical model is achieved. The air pressure and temperature distribution, air flow pattern and resistance are discussed for different cage guiding approaches. Air flow and heat transfer performance, are evaluated via field synergy principle, especially for the key contact and lubrication areas. The results show that air pressure dramatically increases at ultra high rotation speed. The maximums of internal flow velocity, resistance, synergy angle and dynamic pressure around the ball occur under outer ring guiding condition. When the rotating speed is higher than 3.0×104r·min-1, new vortex appears near the entrance of inner raceway contact area, which induces the increase of synergy angle and the decline of flow performance. © 2017 Journal of Mechanical Engineering.
Keyword ：
Airflow patterns Cage guiding approaches Dynamic pressures Field synergy principle Lubrication performance Rotating coordinate system Structure characteristic Ultra high speed
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| GB/T 7714 | Wang, Yatai , Yan, Ke , Zhu, Yongsheng et al. Investigation on internal air flow pattern of angular contact ball bearing with different cage guiding approaches [J]. | Jixie Gongcheng Xuebao/Journal of Mechanical Engineering , 2017 , 53 (1) : 72-78 . |
| MLA | Wang, Yatai et al. "Investigation on internal air flow pattern of angular contact ball bearing with different cage guiding approaches" . | Jixie Gongcheng Xuebao/Journal of Mechanical Engineering 53 . 1 (2017) : 72-78 . |
| APA | Wang, Yatai , Yan, Ke , Zhu, Yongsheng , Hong, Jun , Zhang, Youyun . Investigation on internal air flow pattern of angular contact ball bearing with different cage guiding approaches . | Jixie Gongcheng Xuebao/Journal of Mechanical Engineering , 2017 , 53 (1) , 72-78 . |
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Abstract ：
Diesel engines, widely used in engineering, are very important for the running of equipments and their fault diagnosis have attracted much attention. In the past several decades, the image based fault diagnosis methods have provided efficient ways for the diesel engine fault diagnosis. By introducing the class information into the traditional non-negative matrix factorization (NMF), an improved NMF algorithm named as discriminative NMF (DNMF) was developed and a novel imaged based fault diagnosis method was proposed by the combination of the DNMF and the KNN classifier. Experiments performed on the fault diagnosis of diesel engine were used to validate the efficacy of the proposed method. It is shown that the fault conditions of diesel engine can be efficiently classified by the proposed method using the coefficient matrix obtained by DNMF. Compared with the original NMF (ONMF) and principle component analysis (PCA), the DNMF can represent the class information more efficiently because the class characters of basis matrices obtained by the DNMF are more visible than those in the basis matrices obtained by the ONMF and PCA. (C) 2017 Elsevier Ltd. All rights reserved.
Keyword ：
Diesel engine Discriminative non-negative matrix factorization (DNMF) Fault diagnosis K-nearest neighborhood method Time-frequency distribution
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| GB/T 7714 | Yang Yong-sheng , Ming An-bo , Zhang You-yun et al. Discriminative non-negative matrix factorization (DNMF) and its application to the fault diagnosis of diesel engine [J]. | MECHANICAL SYSTEMS AND SIGNAL PROCESSING , 2017 , 95 : 158-171 . |
| MLA | Yang Yong-sheng et al. "Discriminative non-negative matrix factorization (DNMF) and its application to the fault diagnosis of diesel engine" . | MECHANICAL SYSTEMS AND SIGNAL PROCESSING 95 (2017) : 158-171 . |
| APA | Yang Yong-sheng , Ming An-bo , Zhang You-yun , Zhu Yong-sheng . Discriminative non-negative matrix factorization (DNMF) and its application to the fault diagnosis of diesel engine . | MECHANICAL SYSTEMS AND SIGNAL PROCESSING , 2017 , 95 , 158-171 . |
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Abstract ：
The film pressure of a microgap water-lubricated hybrid journal bearing (HJB) was investigated in this article. The pressure transmission system (PTS) formed by the flow exchange from clearance to the membrane of the sensor was also studied. Three static loads, five rotational speeds, and five water supply pressures were used in this study. The pressure was obtained from a microgap water-lubricated HJB test rig. The experimental results showed that the variation trend of the film pressure agreed with the theoretical results except that the pressure values were lower than the theoretical data. The experimental results should be corrected by the PTS to reflect the real film pressure. The influence of PTS should be considered to improve the precision of experimental results of microgap HJBs.
Keyword ：
microgap Pressure measurement pressure transmission system water-lubricated hybrid journal bearing
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| GB/T 7714 | Li, Pengju , Zhu, Yongsheng , Yan, Ke et al. Experimental Investigation on the Film Pressure Measurement in Microgap Water-Lubricated Hybrid Journal Bearing [J]. | TRIBOLOGY TRANSACTIONS , 2017 , 60 (5) : 814-823 . |
| MLA | Li, Pengju et al. "Experimental Investigation on the Film Pressure Measurement in Microgap Water-Lubricated Hybrid Journal Bearing" . | TRIBOLOGY TRANSACTIONS 60 . 5 (2017) : 814-823 . |
| APA | Li, Pengju , Zhu, Yongsheng , Yan, Ke , Xiong, Qingqing , Zhang, Youyun . Experimental Investigation on the Film Pressure Measurement in Microgap Water-Lubricated Hybrid Journal Bearing . | TRIBOLOGY TRANSACTIONS , 2017 , 60 (5) , 814-823 . |
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Abstract ：
In this paper, a high-resolution front tracking method was presented for interface tracking simulation with Runge-Kutta discontinuous Galerkin methods. An interface treating method of the discontinuous methods is presented. This method don't construct the ghost fluid and the flow information on both sides next to the interface is used to solve the interfacial status. The limiter adopted the combination of the shock detection and monotonicity-preserving limiter and level set method is used for tracking the interface. Result shown that the front tracking of the high-order accurate Runge-Kutta discontinuous Galerkin method exhibits very good agreement with exact solution in the interface condition that contain strong shock.
Keyword ：
Discontinuous methods Front Tracking method High resolution Interface conditions Interface treating method Level-set techniques Monotonicity Runge-kutta discontinuous galerkin methods
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| GB/T 7714 | Zhang, Xu-Jiu , Zhu, Yong-Sheng , Yan, Ke et al. A front tracking method based on Runge-Kutta discontinuous Galerkin methods [J]. | International Journal of Online Engineering , 2016 , 12 (12) : 67-70 . |
| MLA | Zhang, Xu-Jiu et al. "A front tracking method based on Runge-Kutta discontinuous Galerkin methods" . | International Journal of Online Engineering 12 . 12 (2016) : 67-70 . |
| APA | Zhang, Xu-Jiu , Zhu, Yong-Sheng , Yan, Ke , Zhang, You-Yun . A front tracking method based on Runge-Kutta discontinuous Galerkin methods . | International Journal of Online Engineering , 2016 , 12 (12) , 67-70 . |
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Abstract ：
The preloading process is essential for circumferential bolted rotors with curvic couplings and preloading effects determining the rotor performance. A nonuniform clamp load of each bolt will destroy the periodicity of the rotor and affect its strength, stiffness, and stability. In this paper, the finite element method was adopted, the influence of elastic interaction on two types of preload methods (one by one and group) was investigated and the mechanism about elastic interaction was analyzed, and a method to achieve a uniform clamp force of spindle bolts was proposed. This method is based on displacement, and by ensuring equal relative displacements of each bolt and nut during the preloading process, the uniform clamp force can be obtained. The validity of the proposed method is experimentally verified.
Keyword ：
Curvic coupling elastic interaction preload spindle bolt tightening method
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| GB/T 7714 | Yuan, Shuxia , Zhang, Youyun , Fan, Yuguang et al. A method to achieve uniform clamp force in a bolted rotor with curvic couplings [J]. | PROCEEDINGS OF THE INSTITUTION OF MECHANICAL ENGINEERS PART E-JOURNAL OF PROCESS MECHANICAL ENGINEERING , 2016 , 230 (5) : 335-344 . |
| MLA | Yuan, Shuxia et al. "A method to achieve uniform clamp force in a bolted rotor with curvic couplings" . | PROCEEDINGS OF THE INSTITUTION OF MECHANICAL ENGINEERS PART E-JOURNAL OF PROCESS MECHANICAL ENGINEERING 230 . 5 (2016) : 335-344 . |
| APA | Yuan, Shuxia , Zhang, Youyun , Fan, Yuguang , Zhang, Yingchun . A method to achieve uniform clamp force in a bolted rotor with curvic couplings . | PROCEEDINGS OF THE INSTITUTION OF MECHANICAL ENGINEERS PART E-JOURNAL OF PROCESS MECHANICAL ENGINEERING , 2016 , 230 (5) , 335-344 . |
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Abstract ：
Most liquid lubricating systems are inevitably supplied with lubricant containing contaminant particles. It is certain that some of these particles are suspended in the oil, that is, the size of the solid particle is smaller than the oil film thickness. In this paper, the effects of the suspended particles on the oil film pressure of cylinder-piston ring were mainly studied. In recent years, the lattice Boltzmann method (LBM) has been developed as an alternative to the conventional CFD (Computational Fluid Dynamics) methods. Unlike conventional numerical schemes based on discretization of macroscopic equations, the LBM is based on the statistical physics and describes the microscopic picture of particles movement in an extremely simplified way, but at the macroscopic level it gives a correct average description of the motion. It has been widely used to simulate the two-phase flow. The paper is aimed to study the influence of solid particles on the oil film pressure of piston ring based on L. The lubricate oil with suspended particles was regarded as the two-phase flow. The movement of the lubricate oil with solid particles is described with kinetic equations of distribution function of particles. A discrete Lattice-Boltzmann model of cylinder-piston ring was built in the domain of piston ring lubrication from the perspective of flow field. The implementation of boundary conditions for LBM is very important and has great effect on the accuracy and the stability of method. The bounce-back scheme was used in fluid-solid boundary and wall boundary treatment. The Reynolds boundary condition in the Lattice-Boltzmann Method was developed for the cracked oil film. By programming simulation, the influence of solid particles on the oil film pressure of piston ring was studied by researching the flow of the lubricant with solid particles based on LBM. The effect of particle location, shape and number on the oil film pressure of piston ring at certain crank angle was analyzed. The influence of solid particles on the oil film pressure of cylinder-piston ring was studied at different crank angle. Oil film velocity of lubricant was simulated base on LBM, and the simulated results were compared with the experimental results. The results of simulation agreed with experimental result well. It was shown in the results that the effect of the particle on the film pressure in piston ring lubrication was more significant, if the distance between the ring and particle center was closer. The variation of oil film pressure was 34.6% compared to the oil film pressure without particles. Conversely, the effect on the pressure was slight when the distance was greater, and the variation of oil film pressure was 11.2% compare to the oil film pressure without particles. When the thickness of particle was same, the influence of the longer particle on the oil film was more significant. The effects of particles on the oil film pressure were slight during the suction stroke and compression stroke. The variation of oil film pressure was 2.85% compared to the oil film pressure without particles at crank angle φ=320°. Then, the influence of particles on the oil film pressure of piston ring was more significant during the power stroke. The variation of oil film pressure was 3.95% compare to the oil film pressure without particles at φ=450°. Moreover, the experimental phenomenon that the abrasion was severe at dead centers of the engine, was theoretically analyzed. The study will provide theoretical reference for structural optimization of cylinder-piston ring. © 2016, Chinese Society of Agricultural Engineering. All right reserved.
Keyword ：
CFD (computational fluid dynamics) Lattice boltzmann Lattice Boltzmann method Lattice boltzmann methods (LBM) Lubricating systems Macroscopic equation Oil film pressure Suspended particles
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| GB/T 7714 | Han, Haiyan , Zhang, Youyun , Wang, Kai . Influences of solid particles on oil film pressure in cylinder-piston ring based on lattice-Boltzmann method [J]. | Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering , 2016 , 32 (11) : 109-116 . |
| MLA | Han, Haiyan et al. "Influences of solid particles on oil film pressure in cylinder-piston ring based on lattice-Boltzmann method" . | Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering 32 . 11 (2016) : 109-116 . |
| APA | Han, Haiyan , Zhang, Youyun , Wang, Kai . Influences of solid particles on oil film pressure in cylinder-piston ring based on lattice-Boltzmann method . | Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering , 2016 , 32 (11) , 109-116 . |
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Abstract ：
In the fault diagnosis field of mechanical equipment, the result of analyzing the collected monitoring data from the equipment is often the high dimensionality of images which contain mass data; so the method of extracting sensitive feature from the high-dimensional information or image is a key technology. We present a new method for fault diagnosis of mechanical equipment based on Multi-Kernel Non-negative Matrix Factorization (MKNMF), which overcomes the defect that the traditional fault diagnosis of mechanical equipment requires signal feature extraction this defect causes loss of information; we reduce dimensions for high dimension information through applying Multi-Kernel Non-negative Matrix Factorization method and then distinguish the dimensionality reduction data with Multi-Kernel Support Vector Machine (MKSVM). The experiments and their analysis show preliminarily that this method can reduce the dimensions of the original monitored data and improve the recognition rate of machine fault diagnosis. ©, 2015, Xibei Gongye Daxue Xuebao/Journal of Northwestern Polytechnical University. All right reserved.
Keyword ：
Data dimensionality reduction Dimensionality reduction Fault diagnosis technology High dimensionality Machine fault diagnosis Mechanical equipment Multi-kernel Nonnegative matrix factorization
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| GB/T 7714 | Yang, Yongsheng , Zhang, Youyun , Zhu, Yongsheng . The fault diagnosis technology of mechanical equipment based on multi-kernel non-negative matrix factorization (MKNMF) [J]. | Xibei Gongye Daxue Xuebao/Journal of Northwestern Polytechnical University , 2015 , 33 (2) : 251-258 . |
| MLA | Yang, Yongsheng et al. "The fault diagnosis technology of mechanical equipment based on multi-kernel non-negative matrix factorization (MKNMF)" . | Xibei Gongye Daxue Xuebao/Journal of Northwestern Polytechnical University 33 . 2 (2015) : 251-258 . |
| APA | Yang, Yongsheng , Zhang, Youyun , Zhu, Yongsheng . The fault diagnosis technology of mechanical equipment based on multi-kernel non-negative matrix factorization (MKNMF) . | Xibei Gongye Daxue Xuebao/Journal of Northwestern Polytechnical University , 2015 , 33 (2) , 251-258 . |
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Abstract ：
在机械设备故障诊断研究领域中，系统采集的原始监测数据经过处理得到的结果往往是数据量很大，维数很高的图像数据，因此，从高维图像中获取敏感特征是当前故障诊断领域中面临的一项关键技术。本文提出了基于多核非负矩阵分解的机械设备故障诊断方法，该方法克服了传统故障诊断需对机械设备信号进行特征提取而造成信息丢失，通过应用多核非负矩阵分解方法进行降维，然后结合多核支持向量机实现对降维后的数据直接进行识别。实验证明该方法可降低原始数据特征的维数，提高分类运算的效率以及故障诊断的识别率。
Keyword ：
多核非负矩阵分解 故障诊断 数据降维 支持向量机
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| GB/T 7714 | 杨永生 , 张优云 , 朱永生 . 基于多核非负矩阵分解的机械故障诊断 [J]. | 西北工业大学学报 , 2015 , (2) : 251-258 . |
| MLA | 杨永生 et al. "基于多核非负矩阵分解的机械故障诊断" . | 西北工业大学学报 2 (2015) : 251-258 . |
| APA | 杨永生 , 张优云 , 朱永生 . 基于多核非负矩阵分解的机械故障诊断 . | 西北工业大学学报 , 2015 , (2) , 251-258 . |
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Abstract ：
The vortex formed around the rolling ball and the high pressure region formed around the ball-raceway contact zone are the principle factors that barricades the lubricant entering the bearing cavity, and further causes improper lubrication. The investigation of the air phase flow inside the bearing cavity is essential for the optimization of the oil-air two-phase lubrication method. With the revolutionary reference frame describing the bearing motion, a highly precise air phase flow model inside the angular contact ball bearing cavity was build up. Comprehensive factors such as bearing revolution, ball rotation, and cage structure were considered to investigate the influences on the air phase flow and heat transfer efficiency. The aerodynamic noise was also analyzed. The result shows that the ball spinning leads to the pressure rise and uneven pressure distribution. The air phase velocity, pressure and cage heat transfer efficiency increase as the revolving speed increases. The operating noise is largely due to the impact of the high speed external flow on the bearing. When the center of the oil-air outlet fixes near the inner ring, the aerodynamic noise is reduced. The position near the inner ring on the bigger axial side is the ideal position to fix the lubricating device for the angular contact ball bearing.
Keyword ：
air phase flow cage structure heat transfer efficiency high speed angular contact ball bearing
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| GB/T 7714 | Zhai Qiang , Yan Ke , Zhang You-yun et al. Air flow patterns and noise analysis inside high speed angular contact ball bearings [J]. | JOURNAL OF CENTRAL SOUTH UNIVERSITY , 2015 , 22 (9) : 3358-3366 . |
| MLA | Zhai Qiang et al. "Air flow patterns and noise analysis inside high speed angular contact ball bearings" . | JOURNAL OF CENTRAL SOUTH UNIVERSITY 22 . 9 (2015) : 3358-3366 . |
| APA | Zhai Qiang , Yan Ke , Zhang You-yun , Zhu Yong-sheng , Wang Ya-tai . Air flow patterns and noise analysis inside high speed angular contact ball bearings . | JOURNAL OF CENTRAL SOUTH UNIVERSITY , 2015 , 22 (9) , 3358-3366 . |
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