为了解离子发动机羽流特别是交换电荷离子(CEX,Charge-Exchange)的分布和流动特性,建立了离子发动机羽流的物理模型,采用粒子网格(PCI,Particle in Cell)方法对2种型号的离子发动机羽流场进行数值模拟计算,与其地面实验数据进行对比分析...为了解离子发动机羽流特别是交换电荷离子(CEX,Charge-Exchange)的分布和流动特性,建立了离子发动机羽流的物理模型,采用粒子网格(PCI,Particle in Cell)方法对2种型号的离子发动机羽流场进行数值模拟计算,与其地面实验数据进行对比分析.结果表明:在CEX离子密度大小及分布、电势的大小及最大电势梯度的位置、CEX离子流动角方面,模拟结果同实验结果符合得相当好.在电势结构方面,由于舱壁电势的影响,模拟结果同实验结果相比有一些差别.羽流模型和计算结果为相关羽流实验和数值模拟研究提供参考.展开更多
In this project,we investigated how ion thrusters produce propulsion and how the design of ion thrusters affects the performance of the thruster.In the experiment,we build a high voltage power supply(0-50 kV)and foil ...In this project,we investigated how ion thrusters produce propulsion and how the design of ion thrusters affects the performance of the thruster.In the experiment,we build a high voltage power supply(0-50 kV)and foil rings to produce ion wind.When considering the design of the thruster,we focus on three variables:the volume of the space,where ions are produced and the electric field intensity.Thus,to investigate the first variable we made foil rings with different radius and change the distance between the ring and positive cathode.To determine the propulsion produced we use a speed sensor to determine the magnitude of the wind produced.展开更多
Homogeneous charge compression ignition(HCCI)gasoline engines have the merit of good fuel economy and very low NOx emissions.The ion current signal in a gasoline direct injection-HCCI engine is the main focus of this ...Homogeneous charge compression ignition(HCCI)gasoline engines have the merit of good fuel economy and very low NOx emissions.The ion current signal in a gasoline direct injection-HCCI engine is the main focus of this paper.Experiments showed that the ion signal is significant correlated with the combustion status.Fuel spray and air-fuel mixture motions significant decrease the signal-to-noise ratio of the ion current signal.However,the current waveforms still vary regularly as the boundary conditions change,and their phases have significant linear relationships with the combustion phases.By combining the analysis with cylinder pressure data,the current can be used to effectively detect the combustion phase when the air fuel mixture is not lean.When the mixture gets leaner,the signal amplitude diminishes dramatically,and the linear correlation decreases substantially.The ratio of two-stage fuel injection has a strong effect on signal amplitude and combustion stability,and the linear relationship between the signal and combustion characteristics becomes insignificant as the pre-injection fuel amount decreases.A reaction kinetics analysis of the mechanism for the ion current signal in the HCCI engine explains the experimental observations.展开更多
Ion optics are crucial components of ion thrusters and the study of the different ion extraction solutions used since the beginning of the electric propulsion era is essential to understand the evolution of ion engine...Ion optics are crucial components of ion thrusters and the study of the different ion extraction solutions used since the beginning of the electric propulsion era is essential to understand the evolution of ion engines. This work describes ion engine grids＇ main functions, parameters and issues related to thermal expansion and sputter erosion, and then introduces a review of ion optics used for significant launched and tested ion thrusters since 1970. Configurations, geometries, materials and fabrication methods are analyzed to understand when typical ion thrusters use two or three grids, what are the thicknesses and aperture sizes of the screen, accelerator and decelerator grids, why molybdenum and carbon-based materials such as pyrolytic graphite and carbon–carbon are the best available options for ion optics and what is the manufacturing method for each material.展开更多
针对未来深空探测任务对高功率电推力器的需求,兰州空间技术物理研究所开展了5 k W环型离子推力器的研制。环型离子推力器放电室设计与传统离子推力器有很大不同,面临着放电不稳定、不均匀、放电损耗过大等潜在的技术风险。在原理样机...针对未来深空探测任务对高功率电推力器的需求,兰州空间技术物理研究所开展了5 k W环型离子推力器的研制。环型离子推力器放电室设计与传统离子推力器有很大不同,面临着放电不稳定、不均匀、放电损耗过大等潜在的技术风险。在原理样机完成设计、制造工作后,开展了试验研究工作,通过性能摸底试验对推力器电气参数变化规律进行研究并找到最佳的工作点,通过等离子体诊断试验对放电室内等离子体密度和电子温度分布情况进行研究。试验结果表明:环型放电室在很宽的放电电流范围内都有很高的稳定性,在单阴极偏置的情况下推力器束流仍然具有较好的均匀性,初步验证了环型离子推力器概念的可行性,为下一步优化设计打下了技术基础。展开更多
文摘为了解离子发动机羽流特别是交换电荷离子(CEX,Charge-Exchange)的分布和流动特性,建立了离子发动机羽流的物理模型,采用粒子网格(PCI,Particle in Cell)方法对2种型号的离子发动机羽流场进行数值模拟计算,与其地面实验数据进行对比分析.结果表明:在CEX离子密度大小及分布、电势的大小及最大电势梯度的位置、CEX离子流动角方面,模拟结果同实验结果符合得相当好.在电势结构方面,由于舱壁电势的影响,模拟结果同实验结果相比有一些差别.羽流模型和计算结果为相关羽流实验和数值模拟研究提供参考.
文摘In this project,we investigated how ion thrusters produce propulsion and how the design of ion thrusters affects the performance of the thruster.In the experiment,we build a high voltage power supply(0-50 kV)and foil rings to produce ion wind.When considering the design of the thruster,we focus on three variables:the volume of the space,where ions are produced and the electric field intensity.Thus,to investigate the first variable we made foil rings with different radius and change the distance between the ring and positive cathode.To determine the propulsion produced we use a speed sensor to determine the magnitude of the wind produced.
基金This research is funded by China Natural Science Foundation(No.51761135105)Shanghai Pu Jiang talent program(18PJ1410000)+1 种基金the Fundamental Research Funds for the Central Universities(22120180307)Development Project of Knowledge Service Platform in Shanghai Compliance with Ethical Standards。
文摘Homogeneous charge compression ignition(HCCI)gasoline engines have the merit of good fuel economy and very low NOx emissions.The ion current signal in a gasoline direct injection-HCCI engine is the main focus of this paper.Experiments showed that the ion signal is significant correlated with the combustion status.Fuel spray and air-fuel mixture motions significant decrease the signal-to-noise ratio of the ion current signal.However,the current waveforms still vary regularly as the boundary conditions change,and their phases have significant linear relationships with the combustion phases.By combining the analysis with cylinder pressure data,the current can be used to effectively detect the combustion phase when the air fuel mixture is not lean.When the mixture gets leaner,the signal amplitude diminishes dramatically,and the linear correlation decreases substantially.The ratio of two-stage fuel injection has a strong effect on signal amplitude and combustion stability,and the linear relationship between the signal and combustion characteristics becomes insignificant as the pre-injection fuel amount decreases.A reaction kinetics analysis of the mechanism for the ion current signal in the HCCI engine explains the experimental observations.
文摘Ion optics are crucial components of ion thrusters and the study of the different ion extraction solutions used since the beginning of the electric propulsion era is essential to understand the evolution of ion engines. This work describes ion engine grids＇ main functions, parameters and issues related to thermal expansion and sputter erosion, and then introduces a review of ion optics used for significant launched and tested ion thrusters since 1970. Configurations, geometries, materials and fabrication methods are analyzed to understand when typical ion thrusters use two or three grids, what are the thicknesses and aperture sizes of the screen, accelerator and decelerator grids, why molybdenum and carbon-based materials such as pyrolytic graphite and carbon–carbon are the best available options for ion optics and what is the manufacturing method for each material.
文摘针对未来深空探测任务对高功率电推力器的需求,兰州空间技术物理研究所开展了5 k W环型离子推力器的研制。环型离子推力器放电室设计与传统离子推力器有很大不同,面临着放电不稳定、不均匀、放电损耗过大等潜在的技术风险。在原理样机完成设计、制造工作后,开展了试验研究工作,通过性能摸底试验对推力器电气参数变化规律进行研究并找到最佳的工作点,通过等离子体诊断试验对放电室内等离子体密度和电子温度分布情况进行研究。试验结果表明:环型放电室在很宽的放电电流范围内都有很高的稳定性,在单阴极偏置的情况下推力器束流仍然具有较好的均匀性,初步验证了环型离子推力器概念的可行性,为下一步优化设计打下了技术基础。
