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Optimal Design of high-speed Partial Flow Pumps using Orthogonal Tests and Numerical Simulations

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Fluid Dynamics & Materials Processing 2024年第6期20卷 1203-1218页

作者： Jiaqiong Wang Tao Yang Chen Hu Yu Zhang Ling Zhou National Research Center of Pumps Jiangsu UniversityZhenjiangChina Wenling Fluid Machinery Technology Institute of Jiangsu University WenlingChina National Engineering Research Center for Disaster and Emergency Rescue Equipment Army Logistics AcademyChongqingChina

To investigate the influence of structural parameters on the performances and internal flow characteristics of partial flow pumps at a low specific speed of 10000 rpm,special attention was paid to the first and second stage impeller guide vanes.Moreover,the impeller blade outlet width,impeller inlet diameter,blade inclination angle,and number of blades were considered for orthogonal tests.Accordingly,nine groups of design solutions were formed,and then used as a basis for the execution of numerical simulations(CFD)aimed at obtaining the efficiency values and heads for each design solution group.The influence of impeller geometric parameters on the efficiency and head was explored,and the“weight”of each factor was obtained via a range analysis.Optimal structural parameters were finally chosen on the basis of the numerical simulation results,and the performances of the optimized model were verified accordingly(yet by means of CFD).Evidence is provided that the increase in the efficiency and head of the optimized model was 12.11%and 23.5 m,respectively,compared with those of the original model.

关键词： high-speed partial flow pump orthogonal test optimal design numerical calculation

Development of a high-speed digital pulse signal acquisition and processing system based on MTCA for liquid scintillator neutron detector on EAST

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Nuclear Science and Techniques 2023年第10期34卷 60-72页

作者： Yong-Qiang Zhang Li-Qun Hu Guo-Qiang Zhong Hong-Rui Cao Jin-Long Zhao Li Yang Qiang Li Institute of Plasma Physics Hefei Institutes of Physical ScienceChinese Academy of SciencesHefei 230031China University of Science and Technology of China Hefei 230026China Institute of Energy Hefei Comprehensive National Science CenterHefei 230031China

In this experimental study, involving deuterium–deuterium fusion neutron emission spectroscopy measurement on the experimental advanced superconducting tokamak(EAST), a liquid scintillator detector(BC501 A) was employed. This decision was based on the detector's superior sensitivity, optimal time-response, and its exceptional n–γ discrimination capability. This detector emits fast pulse signals that are as narrow as 100 ns, with high count rates that can peak at several Mcps. However, conventional nuclear circuits faced challenges in performing pulse height analysis, n–γ pulse shape discrimination, and in recording the entire pulse waveform under such high count rate conditions. To address these challenges, a high-speed digital pulse signal acquisition and processing system was designed. The system was developed around a micro-telecommunications computing architecture. Within this structure, a signal acquisition and processing(SAQP) module communicated through PCI Express links, achieving a bandwidth of up to 1.6 GB/s. To accurately capture the detailed shape of the pulses, four channels of analog-to-digital converters were used, each with a 500-MSPS sampling rate and a 14-bit resolution, ensuring an accuracy that surpassed 11 bits. An n–γ discrimination algorithm, based on the two-gate integral method, was also developed. Implemented within field programmable gate arrays, this algorithm provided a real-time n–γ discrimination spectrum for pulse height analysis. The system underwent rigorous testing in a laboratory setting and during an EAST experiment. The results confirmed that the innovative SAQP system can satisfy the demanding requirements of high-parameter experiments, manage count rates of up to 2 Mcps, execute real-time n–γ discrimination algorithms, and record entire pulse waveforms without any data loss.

关键词： EAST NES high-speed MTCA n–γdiscrimination Entire pulse waveform

Dynamic deformation behavior and microstructural evolution during high-speed rolling of Mg alloy having non-basal texture

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Journal of Materials Science & Technology 2019年第4期35卷 473-482页

作者： Sang-Hoon Kim Jeong Hun Lee Chong Soo Lee Jonghun Yoon Sung Hyuk Park School of Materials Science and Engineering Kyungpook National University Ulsan Regional Division Korea Institute of Industrial Technology Graduate Institute of Ferrous Technology Pohang University of Science and Technology Department of Mechanical Engineering Hanyang University

The dynamic deformation behaviors and resultant microstructural variations during high-speed rolling(HSR) of a Mg alloy with a non-basal texture are investigated. To this end, AZ31 alloy samples in which the basal poles of most grains are predominantly aligned parallel to the transverse direction(TD) are subjected to hot rolling with different reductions at a rolling speed of 470 m/min. The initial grains with a TD texture are favorable for {10–12} twinning under compression along the normal direction(ND); as a result, {10–12} twins are extensively formed in the material during HSR, and this consequently results in a drastic evolution of texture from the TD texture to the ND texture and a reduction in the grain size. After the initial grains are completely twinned by the {10–12} twinning mechanism, {10–11} contraction twins and {10–11}-{10–12} double twins are formed in the {10–12} twinned grains by further deformation.Since the contraction twins and double twins have crystallographic orientations that are favorable for basal slip during HSR, dislocations easily accumulate in these twins and fine recrystallized grains nucleate in the twins to reduce the increased internal strain energy. Until a rolling reduction of 20%, {10–12}twinning is the main mechanism governing the microstructural change during HSR, and subsequently,the microstructural evolution is dominated by the formation of contraction twins and double twins and the dynamic recrystallization in these twins. With an increase in the rolling reduction, the average grain size and internal strain energy of the high-speed-rolled(HSRed) samples decrease and the basal texture evolves from the TD texture to the ND texture more effectively. As a result, the 80% HSRed sample, which is subjected to a large strain at a high strain rate in a single rolling pass, exhibits a fully recrystallized microstructure consisting of equiaxed fine grains and has an ND basal texture without a TD texture component.

关键词： Magnesium alloy high-speed rolling Texture Dynamic recrystallization Twinning

high-speed Trains Automatic Operation with Protection Constraints: A Resilient Nonlinear Gain-based Feedback Control Approach

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IEEE/CAA Journal of Automatica Sinica 2019年第4期6卷 992-999页

作者： Shigen Gao Yuhan Hou Hairong Dong Sebastian Stichel Bin Ning IEEE the State Key Laboratory of Rail Traffic Control and Safety Beijing Jiaotong UniversityBeijing 100044China the Division of Rail Vehicles KTH Royal Inititute of Technology

This paper addresses the control design for automatic train operation of high-speed trains with protection constraints.A new resilient nonlinear gain-based feedback control approach is proposed,which is capable of guaranteeing,under some proper non-restrictive initial conditions,the protection constraints control raised by the distance-to-go(moving authority)curve and automatic train protection in practice.A new hyperbolic tangent function-based model is presented to mimic the whole operation process of high-speed trains.The proposed feedback control methods are easily implementable and computationally inexpensive because the presence of only two feedback gains guarantee satisfactory tracking performance and closed-loop stability,no adaptations of unknown parameters,function approximation of unknown nonlinearities,and attenuation of external disturbances in the proposed control strategies.Finally,rigorous proofs and comparative simulation results are given to demonstrate the effectiveness of the proposed approaches.

关键词： Automatic train operation high-speed train nonlinear gain feedback protection constraint resilient control

Optimization and verification of free flight separation similarity law in high-speed wind tunnel

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Chinese Journal of Aeronautics 2020年第2期33卷 501-507页

作者： Fei XUE Xin JIN Peihua FENG Han QIN Zenghui JIANG Yuchao WANG Peng BAI China Academy of Aerospace Aerodynamics Beijing 100074China AVIC Chengdu Aircraft Design&Research Institute Chengdu 610091China Beijing Machinery and Electronics Engineering Institute Beijing 100074China

Based on the similarity of separation time,a similarity law optimization method for high-speed weapon delivery test is derived.The typical separation state under wind load is simulated by the numerical method.The real separation data of aircraft,separation data of previous test methods,separation data of ideal wind tunnel test of previous methods,and simulation data of the proposed optimization method are obtained.A comparison of the data shows that the method proposed can improve the performance of tracking.Similarity law optimization starts with the development of motion equations and dynamic equations in the windless state to address the problems of mismatching between vertical and horizontal displacement,and to address the problems of separation trajectory distortion caused by insufficient gravity acceleration of the scaling model of existing light model.The ejection velocity of the model is taken as a factor/vector,and is adjusted reasonably to compensate the linear displacement insufficiency caused by the insufficient vertical acceleration of the light model method,so as to ensure the matching of the vertical and horizontal displacement of the projectile,and to improve the consistency between the test results of high-speed projection and the actual separation trajectory.The optimized similarity law is applicable to many existing free-throwing modes of high-speed wind tunnels.The optimized similarity law is not affected by the ejection velocity and hanging mode of the projectile.The optimized similarity law is suitable not only for the launching of the buried ammunition compartment and external stores,but also for the test design of projectile launching and gravity separation.

关键词： Carrier and missile interference Ejection separation Gravity separation high-speed weapon delivery Multi-body separation Similarity law optimization

Moving Mechanism of a high-speed Insect-scale Microrobot via Electro-magnetically Induced Vibration

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Journal of Bionic Engineering 2021年第3期18卷 662-673页

作者： Xinyi Liu Zhiwei Liu Yangsheng Zhu Jiaming Leng Mingjing Qi Jianmei Huang Xiaojun Yan School of Energy and Power Engineering Beihang UniversityBeijing 100191China National Key Laboratory of Science and Technology on Aero-Engine Aero-thermodynamics Beijing 100191China Beijing Key Laboratory of Aero-Engine Structure and Strength Beijing 100191China Collaborative Innovation Center of Advanced Aero-Engine Beijing 100191China

This paper presents the moving mechanism of a high-speed insect-scale microrobot via electromagnetically induced vibration of two simply supported beams.The microrobot,which has a body length of 12.3 mm and a total mass of 137 mg,can achieve reciprocating lift motion of forelegs without any intermediate linkage mechanisms due to the design of an obliquely upward body tilt angle.The gait study shows that the body tilt angle prevents the forelegs from swinging backward when the feet contact the ground,which results in a forward friction force applied on the feet.During forward movement,the microrobot utilizes the elastic deformation of the simply supported beams as driving force to slide forward and its forelegs and rear legs work as pivots alternatively in a way similar to the movement of soft worms.The gait analysis also indicates that the moving direction of the microrobot is determined by whether its body tilt angle is obliquely upward or downward,and its moving speed is also related to the body tilt angle and as well as the body height.Under an applied AC voltage of 4 V,the microrobot can achieve a moving speed at 23.2 cm s1(18.9 body lengths per second),which is comparable to the fastest speed(20 cm s-1 or 20 body lengths per second)among the published insect-scale microrobots.The high-speed locomotion performance of the microrobot validates the feasibility of the presented actuation scheme and moving mechanism.

关键词： Legged microrobot electromagnetic actuation moving mechanism high-speed

high-speed Mach-Zehnder-OTDR Distributed Optical Fiber Vibration Sensor Using Medium-Coherence Laser

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Photonic Sensors 2018年第3期8卷 203-212页

作者： Yuheng TONG Zhengying LI Jiaqi WANG Honghai WANG Haihu YU National Engineering Laboratory for Fiber Optic Sensing Technology Wuhan University of Technology Wuhan 430070 China

This article presents a high-speed distributed vibration sensing based on Mach-Zehnder-OTDR （optical time-domain reflectometry）. Ultra-weak fiber Bragg gratings （UWFBG）, whose backward light intensity is 2-4 orders of magnitude higher than that of Rayleigh scattering, are used as the reflection markers. A medium-coherence laser can substitute conventional narrow bandwidth source to achieve an excellent performance of distributed vibration sensing since our unbalanced interferometer matches the interval of UWFBGs. The 3 m of spatial resolution of coherent detection and multiple simultaneous vibration sources locating can be realized based on OTDR. The enhanced signal to noise ratio （SNR） enables fast detection of distributed vibration without averaging. The fastest vibration of 25 kHz and the slowest vibration of 10Hz can be detected with our system successfully, and the linearity is 0.9896 with a maximum deviation of 3.46nε.

关键词： high-speed Mach-Zehnder-OTDR ultra-weak fiber Bragg grating array medium-coherence laser optical fiber vibration sensing

Ultralow-power high-speed flip-flop based on multimode Fin FETs

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Science China(Information Sciences) 2016年第4期59卷 83-93页

作者： Kai LIAO Xiaoxin CUI Nan LIAO Tian WANG Dunshan YU Xiaole CUI Institute of Microelectronics Peking University Key Laboratory of Integrated Microsystems Shenzhen Graduate School Peking University

In this paper, we first reconstruct a novel planar static contention-free single-phase-clocked flipflop(S2CFF) based on high-performance fin-type field-effect transistors(FinF ETs) to achieve high speed and ultralow power consumption. Benefiting from better control of the conductive channel, the shorted-gate(SGmode) FinF ET flip-flop obtains a persistent reduction of 56.7% in average power consumption as well as a considerable improvement in timing performance at a typical 10% data switching activity, while the low-power(LP-mode) FinF ET flip-flop promotes the power reduction to 61.8% without appreciable degradation in speed.However, through further analysis of the simulation results, we have revealed an unnecessary energy loss caused by the redundant leaps of internal nodes at the static input ‘0’, which has a noticeable negative impact on total power consumption at low data switching activity. In order to overcome this defect, a conditional precharge technique is introduced to control the charging path, and we demonstrate that the independent-gate(IG-mode)FinF ET is the best option for the added control transistor. The verification results indicate that our optimization reduces the power consumption by more than 50% at low data switching activity with an acceptable area and setup time penalty compared with that of LP-mode FinF ET flip-flop.

关键词： multimode FinF ET flip-flop ultralow-power high-speed high-performance

Length optimization of straight line connecting turnout on main line in high-speed railway station yard

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Journal of Central South University 2017年第5期24卷 1111-1120页

作者：尹国栋时瑾魏庆朝来琳 School of Civil Engineering Beijing Jiaotong UniversityBeijing 100044China China Railway Design Corporation Tianjin 300142China

Taking the development of high-speed railway in China as background, and referring to the dynamic theory and wheel-rail contact mode, dynamic analysis model was established, considering the setting position of straight lines and running conditions of train in high-speed railway station yard. Using the established model, and choosing vehicle lateral acceleration and wheel suspension as the evaluation indexes, dynamic characteristic of vehicle traveling in turnout and adjacent area on main line was analyzed, and effects on travelling safety and stability of train aroused by length variation of straight lines were calculated based on analyzing the damping rules of vibration. The results show that, a certain length of straight lines can alleviate the vibration aroused in turnout and curve(turnout), length of straight lines connecting turnouts in different sections on main line was proposed to meet the demand of traveling stability, and shortening or cancelation of straight line for the scale limitation of station yard has less influence on operation safety of train.

关键词： high-speed railway station yard straight line turnout dynamic theory length optimization