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LIPS-300多模式离子推力器中和器优化研究 总被引:1,自引:0,他引:1
中和器与束流的兼容性是影响多模式离子推力器长寿命的关键因素之一,在整个寿命周期内,中和器必须工作在斑状模式。采用数值仿真与实验方法,对LIPS-300离子推力器5 k W工况束流全中和状态下束流区电势分布进行了仿真分析,研究了推力器5 k W工况下中和器供给流率变化对其触持极电参数的影响,分别对推力器工作在5 k W、4 k W和3 k W时,中和器触持极电参数随氙气流率的变化关系进行了测试和分析,提出了多模式推力器中和器流率的最佳选择建议。研究成果对后续多模式离子推力器参数优化具有一定参考。 相似文献
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基于DEA和性能模糊标度的机械设计概念方案评估方法 总被引:2,自引:0,他引:2
给出了概念设计方案性能的模糊标度方法;从价值工程原理出发,通过将数据包络分析(DEA)模型推广到模糊环境之中,提出了一种机械设计概念方案评估的新方法,通过实例应用,验证了该方法的可行性。 相似文献
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Since the high efficiency discharge is critical to the radio-frequency ion thruster (RIT),a 2D axial symmetry hybrid model has been developed to study the plasma evolution of RIT.The fluid method and the drift energy correction of the electron energy distribution function (EEDF) are applied to the analysis of the RIT discharge.In the meantime,the PIC-MCC method is used to investigate the ion beam current extraction character for the plasma plume region.The beam current simulation results,with the hybrid model,agree well with the experimental results,and the error is lower than 11%,which shows the validity of the model.The further study shows there is an optimal ratio for the radio-frequency (RF) power and the beam current extraction power under the fixed RIT configuration.And the beam extraction efficiency will decrease when the discharge efficiency beyond a certain threshold (about 87 W).As the input parameters of the hybrid model are all the design values,it can be directly used to the optimum design for other kinds of RITs and radio-frequency ion sources. 相似文献
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In order to study the influence of three-grid assembly thermal deformation caused by heat accumulation on breakdown times and an ion extraction process,a hot gap test and a breakdown time test are carried out to obtain thermal deformation of the grids when the thruster is in 5 k W operation mode.Meanwhile,the fluid simulation method and particle-in-cell-Monte Carlo collision(PICMCC) method are adopted to simulate the ion extraction process according to the previous test results.The numerical calculation results are verified by the ion thruster performance test.The results show that after about 1.2 h operation,the hot gap between the screen grid and the accelerator grid reduce to 0.25–0.3 mm,while the hot gap between the accelerator grid and the decelerator grid increase from 1 mm to about 1.4 mm when the grids reach thermal equilibrium,and the hot gap is almost unchanged.In addition,the breakdown times experiment shows that 0.26 mm is the minimal safe hot gap for the grid assembly as the breakdown times improves significantly when the gap is smaller than this value.Fluid simulation results show that the plasma density of the screen grid is in the range 6?×10~(17)–6?×?10~(18) m~(13) and displays a parabolic characteristic,while the electron temperature gradually increases along the axial direction.The PIC-MCC results show that the current falling of an ion beam through a single aperture is significant.Meanwhile,the intercepted current of the accelerator grid and the decelerator grid both increase with the change in the hot gap.The ion beam current has optimal perveance status without thermal deformation,and the intercepted current of the accelerator grid and the decelerator grid are 3.65 m A and 6.26 m A,respectively.Furthermore,under the effect of thermal deformation,the ion beam current has over-perveance status,and the intercepted current of the accelerator grid and the decelerator grid are 10.46 m A and 18.24 m A,respectively.Performance test results indicate that the breakdown times increase obviously.The intercepted current of the accelerator grid and the decelerator grid increases to 13 m A and 16.5 m A,respectively,due to the change in the hot gap after 1.5 h operation.The numerical calculation results are well consistent with performance test results,and the error comes mainly from the test uncertainty of the hot gap. 相似文献
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在分析了当今制造企业对工艺知识资源服务与管理的迫切需求的基础上,提出了基于Web的工艺知识资源服务与管理系统,该系统面向企业内部网(Intranet),包括前台工艺知识资源服务系统和后台工艺知识资源管理系统两部分,前台系统为制造企业内部人员提供知识检索服务,后台系统作为工艺知识管理工具和前台的动态维护工具,文中介绍了系统的结构和功能以及关键实现技术。 相似文献
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汽车用组合开关性能试验台的控制系统 总被引:1,自引:1,他引:1
介绍一种汽车组合开关综合性能试验台的控制系统。该试验台控制系统采用PC机为其控制主机,步进电机驱动,具有在线测量组合开关实际力特性的功能。通过C++Builder语言编程,应用API函数实现计算机与试验台整机系统的接口,从而实现了计算机对整个系统的控制。 相似文献
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为了确定对紫外线预报的有效方法,在现有紫外线观测数据基础上。使用逐步回归方法和灰色系统理论分别建立预测模型,并对两种模型的结果进行拟合分析和比较。结果表明,灰色预测方法同样具有较高的准确度,比较简单,计算量少,而逐步回归方法效果稳定,两种预报方法在对紫外线预报中都有很高的价值。 相似文献