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Simulation of SLD Impingement on Wind Turbine Blade Airfoil

Transactions of Nanjing University of Aeronautics and Astronautics 2016年第1期33卷 112-120页

作者： Zhu Chengxiang Zhu Chunling Fu Bin ZhaoHuanyu Key Laboratory of Fundamental Science for National Defense Advanced Design Technology of Flight Vehicle Nanjing University of Aeronautics and AstronauticsNanjing 210016P.R.China Science and Technology on Space Physics Laboratory Beijing 100076P.R.China

Accurate prediction of droplet impingement on wind turbine blade is one of the most important premises of anti-icing and de-icing system *** a super-cooled large droplets(SLD)conditions,droplet no longer maintains a sphere shape,and it may deform,break up,and splash when moving or impinging on the ***-empirical models of droplet dynamic behaviours are embedded into the Eulerian droplet model to improve the accuracy of the numerical simulation of droplet impingement limits and local collection *** droplet model(Model 1)for small droplets and improved Eulerian droplet model(Model 2)for large droplet are both validated by comparing to the wind tunnel experiment *** the proposed methods,droplet impingement limitation and local collection efficiency on the S809 airfoil are calculated in various conditions.A detailed derivation of Model 1and Model 2is presented along with a comparison of numerical trajectories,drag coefficient and collection efficiency *** results show that droplet dynamic behaviours,including splashing,break-up and deforming,must be considered to accurately simulate the impingement behaviour in the SLD *** with the increase of the droplet diameters,the effects of the droplet dynamic behaviors on the impingement characteristics are more obvious.

关键词： wind turbine icing super large droplet droplet deformation splash

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Unified gas-kinetic scheme with multigrid convergence for rarefied flow study

arXiv

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arXiv 2017年

作者： Zhu, Yajun Zhong, Chengwen Xu, Kun National Key Laboratory of Science and Technology on Aerodynamic Design and Research Northwestern Polytechnical University Xi'an Shaanxi710072 China Department of Mathematics Hong Kong University of Science and Technology Hong Kong China

The unified gas kinetic scheme (UGKS) is a direct modeling method based on the gas dynamical model on the mesh size and time step scales. With the implementation of particle transport and collision in a time-dependent ux function, the UGKS can recover multiple ow physics from the kinetic particle transport to the hydrodynamic wave propagation. In comparison with direct simulation Monte Carlo (DSMC), the equations-based UGKS can use the implicit techniques in the updates of macroscopic conservative variables and microscopic distribution function. The implicit UGKS significantly increases the convergence speed for steady ow computations, especially in the highly rarefied and near continuum regime. In order to further improve the computational efficiency, for the first time a geometric multigrid technique is introduced into the implicit UGKS, where the prediction step for the equilibrium state and the evolution step for the distribution function are both treated with multigrid acceleration. More specifically, a full approximate nonlinear system is employed in the prediction step for fast evaluation of the equilibrium state, and a correction linear equation is used in the evolution step for the update of the gas distribution function. As a result, convergent speed has been greatly improved in all ow regimes from rarefied to the continuum ones. The multigrid implicit UGKS (MIUGKS) is used in the non-equilibrium ow study, which includes microow, such as lid-driven cavity ow and the ow passing through a finite-length at plate, and high speed one, such as supersonic ow over a square cylinder. The MIUGKS shows 5 to 9 times efficiency increase over the previous implicit scheme. For the low speed microow, the efficiency of MIUGKS is several orders of magnitude higher than the DSMC. Even for the hypersonic ow at Mach number 5 and Knudsen number 0:1, the MIUGKS is still more than 100 times faster than the DSMC method for a convergent steady state solution. Copyright © 2017, The

关键词： Distribution functions

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Preliminary analysis of FCM fuel thermal-mechanical performance under normal and transient conditions

Preliminary analysis of FCM fuel thermal-mechanical performa...

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Top Fuel 2016: LWR Fuels with Enhanced Safety and Performance

作者： Li, Wenjie Tang, Changbing Liu, Zhenhai Li, Wei Chen, Ping Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China Chengdu610213 China Design Sub-institute Nuclear Power Institute of China Chengdu610213 China

ISBN: (纸本)9780894487309

FCM fuel is a candidate fuel form to replace commercial UO2 fuel rod in LWR to enhance fuel reliability under accident conditions. The FCM pellet consists of TRISO particles embedded inside the dense SiC matrix. This fuel design is more complex than conventional LWR fuel, which needs new fuel performance models or analysis tools to assist fuel design and concept evaluation. In this paper an attempt was made to develop a finite element method to analyze FCM fuel pellet thermal-mechanical performance. Three idealized cases of normal operation, power ramp, and LOCA were analyzed. The results showed that the temperature distribution and stress distribution of FCM pellet exhibited a strong non-uniformity. The irradiation strain and creep of buffer layer and PyC layers had a strong effect on the mechanical performance of FCM pellet. The hoop stresses of SiC layers and SiC matrix increased significantly during the LOCA and varied with radial positions.

关键词： Finite element method

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Research on Rotational Accuracy of Cylindrical Roller Bearings

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Procedia CIRP 2017年 62卷 380-385页

作者： Yu Yongjian Chen Guoding Li Jishun Xue Yujun School of Mechanical Engineering Northwestern Polytechnical University Xi’an 710072 China Henan Key Laboratory for Machinery Design and Transmission System Luoyang 471003 China School of Mechanical Engineering Henan University of Science and Technology Luoyang 471003 China

To investigate transferring mechanism of form error of bearing elements and rotational accuracy in cylindrical roller bearings, according to the bearing components motion and geometric relationships, a prediction model for rotational accuracy of cylindrical roller bearings based on roundness error of the inner raceway is presented. The effects of roundness error (i.e., amplitude, order) in the inner raceway, the number of rollers and radial clearance on the radial runout of inner ring are analyzed. Analytic solutions of the radial runout of inner ring are deduced when shapes of bearing elements are an ideal circle, which verifies the correctness of the presented model. The results show that the proposed model has better precision accuracy.

关键词： Cylindrical roller bearing Rotational accuracy Radial runout Roundness error Form error

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A novel double-loop control strategy and its precise parameters tuning method

A novel double-loop control strategy and its precise paramet...

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Annual Conference of Industrial Electronics Society

作者： Bofeng Gao Xinchun Lin Shan Gao Zhigang Liang State Key Laboratory of Advanced Electromagnetic Engineering and Technology University of Science and Technology Wuhan P. R. China National Key Laboratory for Vessel Integrated Power System Technology Naval University of Engineering Wuhan P. R. China

With the rapid development of hardware and the improvement of control performance requirements, digital control is widely used in power electronics. And due to the mature analysis methods and convenient implantation, the traditional linear control strategies, such as PID control, are directly applied to the design of digital controllers in industrial application. However, as the control delay and the designing process approximation, most digital controllers do not achieve the desired performance indexes and its parameters need to be tested repeatedly when simply adopting traditional control strategies. In view of this above problems, taking the application in inverter systems as an example, the discrete state space model of the inverter is derived with the consideration of one beat control delay. In order to design the controller accurately, this paper proposes a double-loop control strategy in which proportional controller is used for current loop and PI plus state feedback controller is used for voltage loop. Particularly, the designing process of current loop and voltage loop is relatively independent, and the parameters of the voltage loop controller are precisely calculated according to the indexes of overshoot and bandwidth. The proposed control strategy and its parameters tuning method is verified on a platform of 30kVA 115V/400Hz inverter power.

关键词： Inverters Voltage control Delays Aerospace electronics State feedback IP networks Tuning

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Preliminary analysis of core heat-up for ATFs under accident conditions

Preliminary analysis of core heat-up for ATFs under accident...

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Top Fuel 2016: LWR Fuels with Enhanced Safety and Performance

作者： Li, Wei Chen, Ping Su, Guanghui Qiu, Suizheng Tian, Wenxi Li, Wenjie School of Nuclear Science and Technology Xi'an Jiaotong University Xi'an Shaanxi710049 China Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China Chengdu Sichuan610213 China

ISBN: (纸本)9780894487309

Experience gained in decades of nuclear safety research and previous nuclear accidents direct to the investigation of passive safety system design and accident-tolerant fuel (ATF) system which is now becoming a hot research point in the nuclear energy field. The ATF system is aim at upgrading safety characteristics of the nuclear fuel and cladding in a reactor core where active cooling has been lost, and is preferable or comparable to the conventional UO2-Zr fuel system when the reactor is in normal operation. By virtue of advanced materials with improved basic properties and oxidation resistance, the ATF system is placed high hopes on slowing down the accident progression, allowing wider margin of time for the mitigation measures to be effective. SiC and FeCrAl accident-tolerant claddings and FCM accident-tolerant fuel are considered in this work, as they are receiving more and more attention in china. In this paper, the improved performance of UO2-SiC, UO2-FeCrAl, FCM-SiC and FCM-FeCrAl fuel systems on the core heat-up progress in a pressurized water reactor (PWR) is analyzed by using the best-estimate system code RELAP5 and severe accident analysis program respectively. For this purpose two accident scenarios are selected, e.g., a large break LOCA as a design base accident and an extended station blackout (SBO) severe accident, to reflect the accident-tolerance characteristic of ATFs. Obtained quantitative results show promising safety enhancement in terms of peak cladding temperature (PCT) and recovery of the core coolability for the selected ATF systems, which is beneficial for further down-selections of various kinds of ATF systems.

关键词： Silicon carbide

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Developing A “Polysulfide‐Phobic” Strategy to Restrain Shuttle Effect in Lithium–Sulfur Batteries

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Angewandte Chemie 2019年第34期131卷

作者： Yibo He Yu Qiao Zhi Chang Xin Cao Min Jia Ping He Haoshen Zhou Energy Technology Research Institute National Institute of Advanced Industrial Science and Technology (AIST) 1-1-1 Umezono Tsukuba 305-8568 Japan Graduate School of System and Information Engineering University of Tsukuba 1-1-1 Tennoudai Tsukuba 305-8573 Japan Center of Energy Storage Materials&Technology College of Engineering and Applied Sciences Jiangsu Key Laboratory of Artificial Functional Materials National Laboratory of Solid State Microstructures Collaborative Innovation Center of Advanced Microstructures Nanjing University Nanjing 210093 P. R. China

Inspired by hydrophobic interface, a novel design of “polysulfide‐phobic” interface was proposed and developed to restrain shuttle effect in lithium–sulfur batteries. Two‐dimensional VOPO 4 sheets with adequate active sites were employed to immobilize the polysulfides through the formation of a V−S bond. Moreover, owing to the intrinsic Coulomb repulsion between polysulfide anions, the surface anchored with polysulfides can be further evolved into a “polysulfide‐phobic” interface, which was demonstrated by the advanced time/space‐resolved operando Raman evidences. In particular, by introducing the “polysulfide‐phobic” surface design into separator fabrication, the lithium–sulfur battery performed a superior long‐term cycling stability. This work expands a novel strategy to build a “polysulfide‐phobic” surface by “self‐defense” mechanism for suppressing polysulfides shuttle, which provides new insights and opportunities to develop advanced lithium–sulfur batteries.

关键词： Coulomb-Abstoßung Lithium-Schwefel-Batterien Operando-Raman-Spektroskopie Polysulfid-phobe Grenzfläche Verankerte Polysulfide

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Fuel assembly design for supercritical water-cooled reactor

Fuel assembly design for supercritical water-cooled reactor

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作者： Linna, Feng Fawen, Zhu Science and Technology on Reactor System Design Technology Laboratory Third Section of Huafu Road Huayang Town Shuangliu County Chengdu Sichuan Province610213 China

The supercritical water-cooled reactor (SWCR) has been selected as one of the most promising reactors for Generation IV nuclear reactors due to its higher thermal efficiency and more simplified structure compared to the state-of-the-art light water reactors (LWRs). However, there are a large number of potential problems that must be addressed, particularly the fuel assembly design of the SCWR. SCWRs are a kind of high-temperature, high-pressure, water-cooled reactor that operates above the thermodynamic critical point of water (374°C, 22.1 MPa). Corrosion and degradation of materials used in supercritical water environments are determined by several environment- and material-dependent factors. In particular, irradiation-induced changes in microstructure and microchemistry are major concerns in a nuclear reactor. Many structural materials including alloys and ceramics have been proposed for use as SCWR components or materials for applying protective coatings in SCWRs. In this paper, the present status of supercritical fuel assembly design at home and abroad is reported. According to the special requirements of supercritical core design, a kind of configuration design of fuel assembly with two-flow core and using SiC as cladding material are proposed. The analysis results have shown that the design basically meets the requirements of fuel assembly design, which has good feasibility and performance. Copyright © 2015 by ASME.

关键词： Silicon carbide

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Forecast for Radial Runout of Outer Ring in Cylindrical Roller Bearing

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Procedia CIRP 2017年 62卷 375-379页

作者： Li Jishun Yu Yongjian Xue Yujun Henan Key Laboratory for Machinery Design and Transmission System Luoyang 471003 China School of Mechanical Engineering Henan University of Science and Technology Luoyang 471003 China School of Mechanical Engineering Northwestern Polytechnical University Xi’an 710072 China

The radial runout of outer ringin cylindrical roller bearing is investigated by numerical computation. Considering form error of outer raceway, a forecasting model for the radial runout of outer ring in cylindrical roller bearing is developed to study the influences of roundness error (i.e., amplitude, order) of outer raceway, number of rollers and radial clearance on the radial runout of outer ring. To testify the presented forecasting method, an analysis algorithm for computing the radial runout of outer ring with outer raceway shape of ellipse is derived. The comparison of the prediction results with the analytical results shows that the presented forecasting method has the better forecast precision.

关键词： Cylindrical roller bearing Radial runout of outer ring Roundness error Forecast

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Pickup Manipulator design and Its Kinematics Simulation

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IOP Conference Series: Earth and Environmental science 2018年第4期170卷

作者： Zhongdang Zhang Zhaoqiang Zhang Shitai Ma Haibo Zhou Tianjin University of Technology Tianjin Key Laboratory for Advanced Mechatronic System Design and Intelligent Control Tianjin 300384 China National Demonstration Center for Experimental Mechanical and electrical Engineering Education (Tianjin University of Technology) Tianjin 300384 China

In order to improve the flexibility of the pickup manipulator and solve the problem of picking up small sports balls in training ground such as golfing, tennis, and table tennis, a 5-DOF pickup manipulator structure is designed. According to the pickup task requirements of the manipulator, through theoretical calculations, the 86HS series stepping motor is selected as the driving motors of the front end joints. Based on this, the stepping motor control system is designed to realize the closed-loop control of the manipulator. Then the manipulator model is built using D-H method, the inverse kinematics solution is calculated, and the analysis of kinematic theory is conducted. Finally, the targeted pickup point is selected to carry out case simulation analysis of the manipulator, the motion law of the manipulator is verified to be reasonable and the task of picking up small sports balls is completed.

关键词：

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