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dynamic simulation analysis of molten salt reactor-coupled air-steam combined cycle power generation system

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Nuclear Science and Techniques 2024年第2期35卷 222-233页

作者： Jing-Lei Huang Guo-Bin Jia Li-Feng Han Wen-Qian Liu Li Huang Zheng-Han Yang Shanghai Institute of Applied Physics Chinese Academy of SciencesShanghai 201800China University of Chinese Academy of Sciences Beijing 100049China

A nonlinear dynamic simulation model based on coordinated control of speed and flow rate for the molten salt reactor and combined cycle systems is proposed here to ensure the coordination and stability between the molten salt reactor and power system.This model considers the impact of thermal properties of fluid variation on accuracy and has been validated with Simulink.This study reveals the capability of the control system to compensate for anomalous situations and maintain shaft stability in the event of perturbations occurring in high-temperature molten salt tank outlet parameters.Meanwhile,the control system’s impact on the system’s dynamic characteristics under molten salt disturbance is also analyzed.The results reveal that after the disturbance occurs,the controlled system benefits from the action of the control,and the overshoot and disturbance amplitude are positively correlated,while the system power and frequency eventually return to the initial values.This simulation model provides a basis for utilizing molten salt reactors for power generation and maintaining grid stability.

关键词： Molten salt reactor Combined cycle dynamic characteristic Control

Understanding the failure mechanism towards developing high-voltage single-crystal Ni-rich Co-free cathodes

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Green Energy & Environment 2024年第6期9卷 1045-1057页

作者： Jixue Shen Bao Zhang Changwang Hao Xiao Li Zhiming Xiao Xinyou He Xing Ou Engineering Research Center of the Ministry of Education for Advanced Battery Materials School of Metallurgy and EnvironmentCentral South UniversityChangsha410083China Zhejiang Power New Energy Co. Ltd.Zhuji311899China Material Science and Chemistry Engineering College China University of GeosciencesWuhan430074China

Benefited from its high process feasibility and controllable costs,binary-metal layered structured LiNi_(0.8)Mn_(0.2)O_(2)(NM)can effectively alleviate the cobalt supply crisis under the surge of global electric vehicles(EVs)sales,which is considered as the most promising nextgeneration cathode material for lithium-ion batteries(LIBs).However,the lack of deep understanding on the failure mechanism of NM has seriously hindered its application,especially under the harsh condition of high-voltage without sacrifices of reversible capacity.Herein,singlecrystal LiNi_(0.8)Mn_(0.2)O_(2) is selected and compared with traditional LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)(NCM),mainly focusing on the failure mechanism of Cofree cathode and illuminating the significant effect of Co element on the Li/Ni antisite defect and dynamic characteristic.Specifically,the presence of high Li/Ni antisite defect in NM cathode easily results in the extremely dramatic H2/H3 phase transition,which exacerbates the distortion of the lattice,mechanical strain changes and exhibits poor electrochemical performance,especially under the high cutoff voltage.Furthermore,the reaction kinetic of NM is impaired due to the absence of Co element,especially at the single-crystal architecture.Whereas,the negative influence of Li/Ni antisite defect is controllable at low current densities,owing to the attenuated polarization.Notably,Co-free NM can exhibit better safety performance than that of NCM cathode.These findings are beneficial for understanding the fundamental reaction mechanism of single-crystal Ni-rich Co-free cathode materials,providing new insights and great encouragements to design and develop the next generation of LIBs with low-cost and high-safety performances.

关键词： Li/Ni antisite defect dynamic characteristic High-voltage Single-crystal Ni-rich Co-free cathodes Lithium-ion batteries

dynamic characteristic analysis on hydraulic control system for cutting system of longitudinal roadheaders

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Dynamic characteristic analysis on hydraulic control system ...

Numerical Analysis and Experimental Study on dynamic characteristic of Six-axis Force/torque Table

第一届液压技术与矿山装备国际学术会议

作者： WEI Xiao-hua XIE Miao Liaoning Technical University

dynamic characteristics of the hydraulic control system for the cutting system of roadheaders are very important for analyzing the working performance.This paper supplies the modularization design method for hydraulic control system of cutting system of roadheaders.It utilizes the Matlab/Simulink to establish the mathematical model for each hydraulic components of the cutting system.And the hydraulic control system model is simulated by Matlab/Simulink.It’s useful for predicting and optimize the dynamic response of the hydraulic control system.

关键词： roadheader hydraulic control system dynamic characteristic Simulink

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Numerical Analysis and Experimental Study on Dynamic Charact...

The near-inertial waves observed east of the Philippines

第二届仪器科学与技术国际学术研讨会

作者： LuYimin Liu Zhengshi Chen Xiaodong Ge Yunjian Wang YongHefei University of Technology China Hefei Institute of Intelligent Machine of the Chinese Academy of Science China

＜正＞ In the numerical analysis, elastic body’s FEM （finite element method） model was established and then dynamic analysis was executed by adopting the three dimensional elements to discrete the table and reasonably reduce the boundary conditions of table, Numerical results indicated that first order natural frequency is 439 Hz. In the experimental study, by using the frequency domain methods, we obtained the transfer function of six-axis force/torque table, by means of measuring the impact imposed on the table and response of strain gauge sticking on table’s deformations beam. Experimental results indicated the first natural frequency is about 450Hz. Results of numeric analysis and experimental study were coincident with each other. The results show that the FEM model we established is reasonable and experimental method and test system we adopted are proper.

关键词： Six-axis Force/Torque Table dynamic characteristic numerical analysis experimental study

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Journal of Oceanology and Limnology 2022年第5期40卷 1889-1908页

作者： Shengming YUAN Xiaomei YAN Linlin ZHANG Bing YANG Chongguang PANG Dunxin HU Key Laboratory of Ocean Circulation and Waves Institute of OceanologyChinese Academy of SciencesQingdao 266071China Pilot National Laboratory for Marine Science and Technology(Qingdao) Qingdao 266237China Center for Ocean Mega-Science Chinese Academy of SciencesQingdao 266071China College of Earth Science University of Chinese Academy of SciencesBeijing 100049China

Based on mooring observations from Aug.1,2016 to Dec.14,2017,the characteristics and underlying mechanisms of near-inertial waves(NIWs)observed east of the Philippines were studied.Three strong NIW events were investigated in detail.The NIWs in EventⅠwere induced by typhoon Lan and had the strongest magnitudes of 0.35 m/s.The maximum near-inertial kinetic energy(NIKE)was shown at the ocean surface.The NIW in EventⅡwas stimulated by a moderate cyclonic wind with the extreme NIKE located at about 110-m depth.The existence of a cyclonic eddy during EventsⅠandⅡled to a blue shift of near-inertial frequencies.For EventⅢ,the surface near-inertial signals were also induced by local weak wind,whereas the real generation mechanisms for the subsurface NIWs remain unclear.In particular,during EventⅢ,there was a nonlinear wave-wave interaction between NIWs and semidiurnal(D)tides,which further induced strong D±f waves.Overall,the NIWs in the three events exhibited distinct vertical structures.The NIWs in EventsⅠandⅡwere dominated by lower mode s with elevated NIKE well confined to the upper 250 m and 270 m,respectively.In contrast,the NIW EventⅢwas dominated by higher modes and the NIWs penetrated downward beyond 360 m.Such deep penetration of NIWs could be attributed to the weak wind stress curl and positive sea level anomalies associated with an anticyclonic eddy.In addition,the three NIW events had e-folding timescales of less than 7 days.

关键词： near-inertial wave(NIW) generation mechanism dynamic characteristic

dynamic stiffness characteristics of aero-engine elastic support structure and its effects on rotor systems:mechanism and numerical and experimental studies

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Applied Mathematics and Mechanics(English Edition) 2023年第2期44卷 221-236页

作者： Lei LI Zhong LUO Kaining LIU Jilai ZHOU School of Mechanical Engineering and Automation Northeastern UniversityShenyang 110819China Key Laboratory of Vibration and Control of Aero-Propulsion Systems Ministry of Education of China Northeastern UniversityShenyang 110819China Foshan Graduate School of Innovation Northeastern UniversityFoshan 528312Guangdong ProvinceChina

The support structure of a rotor system is subject to vibration excitation,which results in the stiffness of the support structure varying with the excitation frequency(i.e.,the dynamic stiffness).However,the dynamic stiffness and its effect mechanism have been rarely incorporated in open studies of the rotor system.Therefore,this study theoretically reveals the effect mechanism of dynamic stiffness on the rotor system.Then,the numerical study and experimental verification are conducted on the dynamic stiffness characteristics of a squirrel cage,which is a common support structure for aero-engine.Moreover,the static stiffness experiment is also performed for comparison.Finally,a rotor system model considering the dynamic stiffness of the support structure is presented.The presented rotor model is used to validate the results of the theoretical analysis.The results illustrate that the dynamic stiffness reduces the critical speed of the rotor system and may lead to a new resonance.

关键词： dynamic stiffness squirrel cage rotor system dynamic characteristic critical speed

dynamic characteristics of Multi-degrees of Freedom System Rotor-bearing System with Coupling Faults of Rub-impact and Crack

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Chinese Journal of Mechanical Engineering 2014年第4期27卷 785-792页

作者： REN Zhaohui ZHOU Shihua LI Chaofeng WEN Bangchun School of Mechanical Engineering and Automation Northeastern University

Extensive studies on rotor systems with single or coupled multiple faults have been carried out. However these studies are limited to single-span rotor systems. A finite element model for a complex rotor-bearing system with coupled faults is presented. The dynamic responses of the rotor-bearing system are obtained by using the rotor dynamics theory and the modern nonlinear dynamics theory in connection with the continuation-shooting algorithm（commonly used for obtaining a periodic solution for a nonlinear system） for a range of rub-impact clearances and crack depths. The stability and Hopf instability of the periodic motion of the rotor-bearing system with coupled faults are analyzed by using the procedure described. The results indicate that the finite element method is an effective way for determining the dynamic responses of such complex rotor-bearing systems. Further for a rotor system with rub-impact and crack faults, the influences of the clearances are significantly different for different rub-impact stiffness. On the contrary, the influence of crack depths is rather small. The instability speeds of the rotor-bearing system increase due to the presence of the crack fault. The results obtained using the new finite element model, presented for computation and analysis of dynamic responses of the rotor-bearing systems with coupled faults, are in accordance with measurements in experiment. The formulations given can be used for diagnosis of faults, vibration control, and safe and stable operations of real rotor-bearing systems.

关键词： rotor-bearing system rub-impact crack dynamic characteristic instability

Analysis of the dynamic performance of an electro-hydrostatic actuator and improvement methods

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Chinese Journal of Aeronautics 2018年第12期31卷 2312-2320页

作者： Zhihui LI Yaoxing SHANG Zongxia JIAO Yan LIN Shuai WU Xiaobin LI School of Automation Science and Electrical Engineering Beihang UniversityBeijing 100083China Science and Technology on Aircraft Control Laboratory Beihang UniversityBeijing 100083China

As a kind of actuation mechanism for power-by-wire(PBW) actuation systems of more/all electrical aircraft, an electro-hydrostatic actuator(EHA) is a highly integrated local hydraulic actuation system. It is a volume control system consisting of a motor, a pump, an actuator, etc.,which has features of high efficiency and reliability. However, the poor dynamic characteristic is one of the main factors restricting its wide application in aircraft. In this paper, the reason for the poor dynamic characteristic of an EHA is revealed from the perspectives of the natural frequency characteristic and the power requirement, respectively. In other words, the insufficiency of the motor output power at a high frequency is the main factor causing the poor dynamic characteristic of the system, and methods which include increasing the maximum output torque of the motor, reducing the rotational inertia of the motor-pump group, and adopting a double-motorpump group configuration are proposed in this paper, by which the dynamic characteristic of the system can be improved. The feasibility of those methods are verified by simulations. Finally, the dynamic characteristic is tested on an EHA prototype, and results show that saturation of the output torque of the motor is the main factor restricting the dynamic characteristic of the EHA system.

关键词： dynamic characteristic Motor-pump group Power requirement Rotational inertia

Model test on dynamic characteristics of invert and foundation soils of high-speed railway tunnel

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Earthquake Engineering and Engineering Vibration 2015年第3期14卷 549-559页

作者： Huang Juan Yuan Tieying Peng Limin Yu Jun Ding Zude School of Civil Engineering Central South University Faculty of Civil Engineering and Mechanics Kunming University of Science and Technology

A dynamic model test(CL = 4) at different velocities of train,namely different loading frequencies,is carried out to study the dynamic characteristics of a high-speed railway tunnel invert and its foundation soils.Not only are the accelerations,dynamic coefficients,dynamic stresses of the invert and foundation soils emphatically analyzed,their relationship with the velocity of the train are discussed in detail.Through laboratory testing,the attenuation of vibration propagating from up the rails is obtained and the calculation formula of the speed influence coefficient of the tunnel invert is preliminarily established.The depth of the foundation soils influenced by vibration is also determined in this study.It is shown that the responses of the tunnel invert and foundation soils to vibration are slightly increased with the velocity of the train;circumferential stresses in the bottom of the invert are tensile stresses and maximum stresses appear under the foot of the rails;the dynamic soil pressures of the foundation decrease quickly with the distance away from the tunnel invert and an exponential relationship exists between them.

关键词： high speed railway tunnel dynamic characteristic m