超导可倾瓦磁液复合轴承的动力学特性分析  

Analysis on the Dynamic Characteristics of Superconducting Tilting Pad Magnetic Fluid Composite Bearings

作　　者：闫岗 金英泽[1] 陈晖 苗旭升 金路 许吉敏 袁小阳[1] YAN Gang;JIN Yingze;CHEN Hui;MIAO Xusheng;JIN Lu;XU Jimin;YUAN Xiaoyang(Key Laboratory of Education Ministry for Modern Design and Rotor-Bearing System,Xi’an Jiaotong University,Xi’an 710049,China;Turbopump Research Room,Xi’an Aerospace Propulsion Institute,Xi’an 710100,China;Institute of Tribology,Hefei University of Technology,Hefei 230009,China)

机构地区：[1]西安交通大学现代设计及转子轴承系统教育部重点实验室,西安710049 [2]西安航天动力研究所涡轮泵研究室,西安710100 [3]合肥工业大学机械工程学院摩擦学研究所,合肥230009

出　　处：《西安交通大学学报》2020年第11期65-73,共9页Journal of Xi'an Jiaotong University

基　　金：国家自然科学基金资助项目(51775412);国家自然科学基金青年科学基金资助项目(51805131)。

摘　　要：针对我国新一代液体火箭涡轮泵高速、可重复使用的功能需求与现役滚动轴承直径与转速的乘积(DN值)难以提高之间的矛盾,提出了一种新型超导可倾瓦磁液复合轴承,能够实现磁液优势互补、启停磨损性能和高速振动稳定性综合较优,从而成倍地提高涡轮泵转速并延长其使用寿命。通过涡轮泵系统自带的低温介质,实现了超导磁力与动压液膜力的复合;基于磁通冻结镜像模型和雷诺方程,建立了考虑超导体场冷高度和低黏介质流态的磁液复合分析模型;对于磁场与流场之间的热效应、瓦摆效应和介磁效应的耦合关系,提出了解耦的分析方法;研究了不同设计参数对复合轴承轴心轨迹和动态最小膜厚的影响,揭示了复合轴承的非线性动力学规律。研究结果表明:最佳支点系数在62%~66%之间,可以显著改善轴承的服役性能;在0.04%~0.05%之间存在一个会使最小膜厚出现极小值的间隙比;增大长径比对轴承性能的改善最为明显,增大瓦包角对轴承性能的改善效果微弱;载荷作用在瓦块之间时,复合轴承具有更好的动态承载能力。可为抑制轴颈振动和提高复合轴承承载能力提供一些设计指导,对设计高可靠性火箭涡轮泵的轴系结构也具有一定的参考价值。In view of the contradiction between the high-speed and reusable functional requirements of China’s new-generation liquid rocket turbo pumps and the difficulty of increasing the DN value of active rolling bearings,a new type of superconducting tilting-pad magnetic-fluid composite bearing is proposed,which can achieve complementary advantages of magnetic fluid.The start-stop wear performance and high-speed vibration stability are comprehensive,which doubles the speed of the turbo pump and prolongs its service life.The combination of superconducting magnetic force and dynamic pressure liquid film force is realized through the low temperature medium that comes with the turbo pump system.Based on the magnetic flux freezing-mirror model and Reynolds equation,a magnetic-hydraulic composite analysis model considering the superconductor-field cold height and the flow state of low-viscosity media is established.Aiming at the coupling relationship of the thermal effect,the pad swing effect and the dielectric magnetic effect between magnetic field and flow field,a decoupling analysis method is proposed.The effects of different design parameters on the axis trajectory and the dynamic minimum film thickness of the composite bearing are studied,and the nonlinear dynamics of the composite bearing is revealed.The results indicate that there is an optimal pivot offset between62%and 66%,which can significantly improve the service performance of the bearing and that there is an inflection point between the clearance ratio of 0.04%and 0.05%,which will cause a minimum value of the minimum film thickness.Increasing the length-to-diameter ratio is the most obvious improvement in bearing performance,and the effect of increasing the pad arc angle on the bearing performance is weak.When the load acts between the pads,composite bearings have better dynamic performance and load capacity.The research results can provide some design guidance for suppressing journal vibration and improving the bearing capacity of composite bearings.It also h

关 键 词：轴心轨迹 动态最小膜厚 磁液复合轴承 

分 类 号：TH133.3[机械工程—机械制造及自动化]