含有碰摩故障的多盘双转子系统动态特性

建立航空发动机双转子轴承系统的有限元模型,为考察碰摩特征对双转子系统的影响,在考虑转轴剪切效应、惯量分布效应、横向扭转以及系统结构的几何参数等重要影响因素的前提下考察碰摩故障对系统的影响.研究了碰摩间隙等参数变化时对双转子系统动态特性的影响规律.结果表明由于双转子本身结构和转速的影响,转子各处呈现非周期1运动.另外,由于碰摩影响,整个系统会出现非线性响应,但由于中介轴承的影响在无碰摩故障的转轴上非周期运动稍弱一些.中介轴承除了有耦合作用外,还起到了隔振的作用.     

双转子多盘转子系统的动态特性

采用有限元法建立了双转子-轴承系统的动力学模型,计算分析了轴承支承刚度和内外转子的转速比对系统临界转速的影响,并对计算结果的正确性进行了验证.研究发现:各支承位置支承刚度的增大将使系统临界转速逐渐增大,当增大到一定程度时对临界转速的影响并不大,各支承刚度对各阶临界转速的影响程度并不一致;另外,中介轴承对系统临界转速的影响并不大;以内转子为主激励的同步反进动时,系统临界转速随着转速比的升高而降低,正进动临界转速随着转速比的升高而增大;而以外转子为主激励的同步反进动时的临界转速表现出相反的规律.     

微波法合成聚维酮碘的研究

用微波和正交设计技术研究了碘化钾存在下固相、液相法合成聚维酮碘的工艺条件.液相法中,以乙醇为溶剂探讨了配料比、反应酸度、微波功率、反应时间等因素对聚维酮碘产率的影响.固相法中,以碘化钾为转化剂考察了配料比、微波功率、反应温度和反应时间等因素对聚维酮碘产率的影响.同时,在正交设计试验的基础上,对合成聚维酮碘的条件进行了优化和验证.结果表明,用微波辅助的方法,无论是固相法还是液相法均能够在较短的时间内得到有效碘的含量大于10%的聚维酮碘.     

Calculations of operating schemes for a passive harmonic cavity in HLS-Ⅱ

A passive higher harmonic cavity (HHC) will be used in the Hefei Light Source II Project (HLS-Ⅱ) to lengthen the bunch and consequently increase the beam lifetime dominated by Touschek scattering. The effects of constant voltage and constant detuning have been calculated and compared over the operating current from 0.4 to 0.2 A on the bunch lengthening for the passive normal conducting harmonic cavity system in HLS-Ⅱ. The results show that the bunch shape has less change and the lifetime improvement factors are not less than 2.7 over the beam currents for the constant voltage case. The constant voltage operating scheme may be applied to our machine.     

Preliminary study of the higher-harmoni ccavity for HLS-Ⅱ

A higher-harmonic cavity will be used to increase the beam lifetime and suppress coupled-bunch instabilities for Hefei Light Source-Ⅱ. In this paper, results simulated by the particle-tracking model confirm that tuning in the harmonic cavity may suppress the parasitic coupled-bunch instabilities. The factors calculated for lifetime improvement are larger than 2.5. The 3rd and 4th harmonic cavities have been designed. In particular, the absorbers and antenna couplers are applied in harmonic cavities to damp the higher order modes. Finally, the 4th harmonic cavity similar to the Duke's RF cavity will be used for HLS-Ⅱ.