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A novel optical emission spectroscopy method for diagnostics of contribution of different ionization mechanisms and flux of ions in different valences in discharge channel of a Hall thruster

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Chinese Journal of Aeronautics 2024年第4期37卷 294-307页

作者： Yanfei WANG Ximing ZHU Renqiu ZOU Shilin YAN Junwei JIA Zhongxi NING daren yu School of Energy Science and Engineering Harbin Institute of TechnologyHarbin 150001China Key Laboratory of Aerospace Plasma Propulsion Ministry of Industry and Information TechnologyHarbin 150001China Beijing Orient Institute of Measurement and Test Beijing 100094China Beijing Aerospace Long March Aircraft Research Institute Beijing 100076China

The mass application of Hall thrusters poses the need for a diagnostic method of ionization mechanism in the discharge channel to boost the iteration and optimization of thruster *** work presents an Optical Emission Spectroscopy (OES) method for diagnostics of the contribution of different ionization mechanisms and the flux of ions in different valences in the discharge channel of a Hall *** emission spectra in the discharge channel are analyzed by jointly utilizing a collisional-radiative model,an ionization-excitation model,and a flux-conservation *** is found that the intensities of some spectral lines can be converted into the reaction rates of collision processes,e.g.,electron-induced excitation and ionization *** latter can further be used to determine the evolutions of particle fluxes by utilizing the conservation law of *** novel method is demonstrated on a kilo-watt Hall *** evolutions of several parameters are determined using this method along the discharge channel,including the ionization rates of different mechanisms,particle fluxes,particle densities,and particle *** novel method can be further developed by being jointly utilized with spectral imaging and tomography techniques,enabling diagnostics of multi-dimensional distributions of the above-mentioned parameters in the discharge channel and near-field plume.

关键词： Hall thruster Optical emission spectroscopy Ionization mechanism Particle flux Divalent ion

不同工况和应用场景下CAES-CFP三联产系统特性分析

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Engineering 2024年第3期34卷 233-245页

作者： Jiajia Li Peigang Yan Guowen Zhou Xingshuo Li Qiang Li Jinfu Liu daren yu School of Energy Science and Engineering Harbin Institute of TechnologyHarbin 150001China

To meet the goal of worldwide decarbonization,the transformation process toward clean and green energy structures has *** this context,coal-fired power plant(CFPP)and large-scale energy storage represented by compressed air energy storage(CAES)technology,are tasked with increasing renewable resource accommodation and maintaining the power system *** achieve this,this paper proposes the concept of a CFPP-CAES combined cycle and a trigenerative system based on *** the working conditions of the CFPP,thermal characteristics of three typical operation modes were studied and some general regularities were *** results of various potential integration schemes discussion indicated that extracting water from low-temperature points in the feedwater system to cool pressurized air and simultaneously increase the backwater temperature is beneficial for improving *** addition,preheating the pressurized air before the air expanders via lowgrade water in the feedwater system as much as possible and reducing extracted steam contribute to increasing the *** the optimal integration scheme,2.85 tonnes of coal can be saved per cycle and the round-trip efficiency can be increased by 2.24%.Through the cogeneration of heat and power,the system efficiency can reach 77.5%.In addition,the contribution degree of the three compression heat utilization methods to the performance improvement ranked from high to low,is preheating the feedwater before the boiler,supplying heat,and flowing into the CFPP feedwater *** the cooling energy generation mode,the system efficiency can be increased to over 69%.Regardless of the operation mode,the benefit produced by integration is further enhanced when the CFPP operates at higher operating conditions because the coupling points parameters are *** addition,the dynamic payback period can be shortened by 11.33 years and the internal rate of return increases by 5.20%under a typical app

关键词： Compressed air energy storage CFPP-CAES combined cycle Thermodynamic performance Technical economics

Theoretical Investigation of Operation Modes of MHD Generators for Energy-bypass Engines

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Journal of Thermal Science 2014年第6期23卷 580-585页

作者： Jingfeng Tang Nan Li daren yu Harbin Institute of Technology

A MHD generator with different arrangements of electromagnetic fields will lead the generator working in three modes.A quasi-one-dimensional approximation is used for the model of the MHD generator to analyze the inner mechanism of operation *** the MHD generator with a uniform constant magnetic field,a specific critical electric field E_(cr) is required to decelerate a supersonic entrance flow into a subsonic exit ***,the generator works in a steady mode with a larger electric field than E_(cr) in which a steady supersonic flow is provided at the exit,or the generator works in a choked mode with a smaller electric field than E_(cr) in which the supersonic entrance flow is choked in the *** detailed flow field characteristics in different operation modes are discussed,demonstrating the relationship of operation modes with electromagnetic fields.

关键词： Energy-bypass engines MHD generators Operation modes

基于火-储联合循环的冷热电三联供系统多运行模式热力性能分析

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中国电机工程学报 2024年第9期44卷 3598-3609,I0022页

作者：李佳佳李兴朔周国文颜培刚刘金福于达仁哈尔滨工业大学能源科学与工程学院黑龙江省哈尔滨市150001

综合考虑绝热压缩空气储能及火电机组的特点和不足,该文从能量转化及利用机理出发,提出将二者耦合集成的火-储联合循环概念以及一种基于该循环的新型冷热电多能联供系统,并对该系统进行性能评估和特性分析。基于构建的热力模型,分别研... 详细信息

综合考虑绝热压缩空气储能及火电机组的特点和不足,该文从能量转化及利用机理出发,提出将二者耦合集成的火-储联合循环概念以及一种基于该循环的新型冷热电多能联供系统,并对该系统进行性能评估和特性分析。基于构建的热力模型,分别研究纯电及热电、冷电联产3种典型场景下热能综合利用方式对重要参数及性能的影响规律。结果显示,在最优集成方案下,储能系统的循环效率可提高2.61%。在热电和冷电模式下,循环效率可进一步提升至77%及70.13%。火-储集成能够显著提高能源综合利用水平,在多能联产模式下性能提升更为明显。此外,通过敏感性分析得到典型运行模式下热能利用的合理方式。该文结果能够指导火-储耦合集成系统优化设计及运行,可为火电机组与压缩空气-储能高效发展提供一种新思路。

关键词：压缩空气储能火-储联合循环冷热电联产热力性能

维普期刊数据库博看期刊

Catastrophe,hysteresis and bifurcation of mode transition in scramjet engines and its model

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Science China(Technological Sciences) 2009年第6期52卷 1543-1550页

作者： yu daren CUI Tao BAO Wen Harbin Institute of Technology Harbin 150001China

This paper describes a class of nonlinear phenomena existing in the hypersonic flow and supersonic combustion process of scramjet engines:catastrophe,hysteresis and bifurcation,and further finds out the general rules(topological invariance)for the stability boundaries of mode transition in scramjet *** this topological invariance,a topological approach is put forward to model the stability boundaries,which may contribute to a complexity reduction of high-dimensional modeling when con-sidering more perturbation parameters,and help to explore the physical laws of the nonlinear ***,this paper interprets the characteristic of combustion mode transition based on the cusp topological model in singular theories,and observes the bifurcation characteristic in com-bustion mode ***,a modeling approach is proposed to mathematically describe the stability boundaries of combustion mode transition in scramjet engines,and the model has high ac-curacy comparing to the simulation data,which proves the validation of the basic ideas proposed in this ***,future research directions are proposed.

关键词： scramjet engine catastrophe bifurcation model

Gain Scheduling Control of Nonlinear Shock Motion Based on Equilibrium Manifold Linearization Model

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Chinese Journal of Aeronautics 2007年第6期20卷 481-487页

作者： Cui Tao yu daren Bao Wen Yang Yongbin College of Energy Science and Engineering Harbin Institute of Technology Harbin 150001 China

The equilibrium manifold linearization model of nonlinear shock motion is of higher accuracy and lower complexity over other models such as the small perturbation model and the piecewise-linear model. This paper analyzes the physical significance of the equilibrium manifold linearization model, and the self-feedback mechanism of shock motion is revealed. This helps to describe the stability and dynamics of shock motion. Based on the model, the paper puts forwards a gain scheduling control method for nonlinear shock motion. Simulation has shown the validity of the control scheme.

关键词： shock motion equilibrium manifold linearization gain scheduling control

Magnet stage optimization of 5 kW multi-cusped field thruster

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Plasma Science and Technology 2020年第9期22卷 128-138页

作者： Peng HU daren yu Yan SHEN Beijing Institute of Control Engineering Beijing 100094People's Republic of China Lab of Advanced Space Propulsion Beijing 100094People’s Republic of China Beijing Engineering Research Center of Efficient and Green Aerospace Propulsion Technology Beijing 100094People’s Republic of China Plasma Propulsion Laboratory of Harbin Institute of Technology Harbin 150001People's Republic of China School of Aeronautics and Astronautics Sun Yat-sen UniversityGuangzhou 510006People's Republic of China

The multi-cusped field thruster is a unique electric thruster device,which has many advantages such as long lifetime,large-range thrust throttling ability,high thrust density,and low *** thruster employs several alternating polarity permanent magnets to create a periodic magnetic field with several *** studies have indicated that the basic ionization and acceleration processes are directly related to the electron motion behavior,which mainly depends on the magnetic field *** magnet number and magnet stage length are two key magnetic field parameters that have important effects on the thruster *** this paper,both the magnet number and magnet stage length parameters are studied for the optimization of a 5 k W multi-cusped field *** results indicate that the three-stage thruster has a better electron confinement than the two-stage *** has lower ion energy loss at the wall,and shows a higher ionization ***,the three-stage magnetic field is a superior magnetic field ***,the three-stage magnetic field simulation results indicate that an optimal accelerating electric field distribution and ionization region distribution could be obtained when the magnet length ratio is 78:25:20.

关键词： multi-cusped field magnet number magnet length performance optimization

Impact of exterior electron emission on the self-sustaining margin of hollow cathode discharge

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Plasma Science and Technology 2020年第9期22卷 2-11页

作者： Tianhang MENG Zhongxi NING daren yu Harbin Institute of Technology Harbin 150001.People's Republic of China

Hollow cathode researches used to focus on the inner cavity or downstream plume,however,rarely on the gap between the throttling orifice plate and the keeper plate(T-K gap),which was found to impact the self-sustaining margin of hollow cathode discharge in this *** the lower margin,the main power deposition and electron emission and ionization regions would migrate from inner cavity and downstream plume to the T-K gap,in which case,the source and destination of each m A current therein matter for the self-sustaining *** the metal surfaces in the T-K gap with emissive materials proved effective in lowering the lower margin by supplementing auxiliary thermionic emission,compensating electron loss on cold absorbing walls and suppressing discharge *** doing so,the lower margin of a 4 A hollow cathode was lowered from 1 to 0.1-0.2 A,enabling it to couple with low power Hall thruster without extra keeper current.

关键词： hollow cathode self-sustained discharge secondary electron emission ionization oscillations thermionic emission

Swallowtail model for predicting the global bifurcation behavior of CO oxidation reactions

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Science China Chemistry 2011年第7期54卷 1072-1077页

作者： CUI Tao TANG ShunLin ZHANG Lei yu daren School of Energy Science and Engineering Harbin Institute of Technology Harbin 150001 China Pharmaceutical College Heilongjiang University of Chinese Medicine Institution Harbin 150040 China

Catalytic CO oxidation on platinum group metals exhibits nonlinear phenomena such as hysteresis and *** of the nonlinear mechanisms is important for catalyst design and control of reaction *** studies have offered initial insights into the local bifurcation behavior of CO ***,since the bifurcation behavior of CO oxidation is determined by multiple parameters such as temperature,total flux,and CO fraction,it is difficult to predict the global bifurcation behavior in the resulting high-dimensional parameter *** is for this reason that the observed nonlinear phenomena reflect just the local bifurcation features of CO *** this paper,an elementary chemical law(topological invariance) concerning the bifurcation behavior of CO oxidation on platinum group metals such as Pd(111) is found from a topological *** the elementary law,we put forward a topological approach to model the critical criteria for the reaction hysteresis and *** model may be applied to predict the global bifurcation behavior of CO oxidation in the high-dimensional parameter *** topological approach and the model results may be useful as a guide in thinking about the complex reaction mechanism,designing reaction routes,and actively controlling the bifurcation behavior of the CO oxidation reaction.

关键词： CO oxidation bifurcation hysteresis