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Rotordynamic and thermal analyses of compliant flexure pivot tilting pad gas bearings.

机译：柔性挠性枢轴可倾瓦斯气体轴承的转子动力学和热分析。

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摘要

Rotordynamic and thermal analyses of compliant flexure pivot tilting pad gas bearings were performed. First, compliant flexure pivot tilting pad gas bearings with pad radial compliance (CFTPBs) were introduced and designed for high-speed oil-free micro turbomachinery. The pad radial compliance was for accommodation of large rotor growth at high speeds. Parametric studies on pivot offset, preload, and tilting stiffness were performed using non-linear orbit simulations and coast-down simulations for an optimum design. Second, coast-down tests for imbalance response and stability of typical rotor-bearing system with a rigid rotor and two CFTPBs designed from the above design studies were conducted over operating speeds up to 55 krpm. Prediction of synchronous rotordynamic responses was made in terms of critical speed for various imbalance modes by using a rotordynamic analysis software (XLTRC), combined with dynamic force coefficients from the perturbation analysis. For stability analyses, a generalized orbit simulation program was developed considering both the translational and angular rotor motions with two different bearings. Linear stability analyses for the conical vibration mode were also performed by using XLTRC and the perturbation analysis based on the Lund method. Predictions of whirl speed showed good agreement to the tests, but the estimated onset speed of instability appeared lower than the measured instability. Finally, a new thermo-hydrodynamic analysis model of a typical rotor-bearing system with CFTPBs was presented, accompanying linear perturbation analyses to investigate thermal effects on the rotordynamic performance. A numerical procedure was established for solving the generalized Reynolds equation, the 3-D energy equation, and the associated boundary conditions at the pad inlet flow and solid walls (rotor and pad) simultaneously. Parametric studies were conducted on nominal clearance and external load. Nominal clearance showed significant influence on temperature fields, and external load had uneven thermal effects among pads. Case studies with heat flux and temperature boundary conditions on the rotor end surface were performed to simulate various working conditions of the bearing. Large rotor thermal growth due to the high rotor temperature showed noticeable influence on rotordynamic performance by increasing direct stiffness and damping coefficients.
机译：对柔性挠性枢轴可倾瓦斯气垫轴承进行了转子动力学和热分析。首先，引入了具有轴瓦径向柔度（CFTPBs）的顺应挠性枢轴可倾瓦气体轴承，并设计用于高速无油微型涡轮机械。轴瓦的径向顺应性是为了适应高速时大转子的增长。使用非线性轨道仿真和惯性滑行仿真对枢轴偏移，预紧力和倾斜刚度进行了参数研究，以实现最佳设计。其次，对通过上述设计研究设计的具有刚性转子和两个CFTPB的典型转子轴承系统的不平衡响应和稳定性进行滑行试验，测试的运行速度高达55 krpm。通过使用转子动力学分析软件（XLTRC），结合来自扰动分析的动态力系数，对各种不平衡模式的临界转速进行了同步转子动力学响应的预测。为了进行稳定性分析，考虑到两个不同轴承的平移和角向转子运动，开发了一个通用的轨道仿真程序。还使用XLTRC以及基于Lund方法的扰动分析对圆锥振动模式进行了线性稳定性分析。旋转速度的预测与测试显示出很好的一致性，但是估计的不稳定性开始速度似乎低于测得的不稳定性。最后，提出了一个典型的带有CFTPB的转子轴承系统的热流体动力学分析模型，并伴随线性扰动分析来研究热对转子动力学性能的影响。建立了一个数值程序，用于同时求解广义的雷诺方程，3-D能量方程以及相关联的垫入口流量和固体壁（转子和垫）边界条件。对标称间隙和外部载荷进行了参数研究。标称间隙对温度场有显着影响，并且外部负载在各焊盘之间具有不均匀的热效应。对转子端面上的热通量和温度边界条件进行了案例研究，以模拟轴承的各种工作条件。转子温度高导致转子热增长大，通过增加直接刚度和阻尼系数对转子动力学性能产生了显着影响。

著录项

  • 作者

    Sim, Kyu-Ho.;

  • 作者单位

    Texas A&M University.;

  • 授予单位 Texas A&M University.;
  • 学科 Engineering Mechanical.
  • 学位 Ph.D.
  • 年度 2007
  • 页码 158 p.
  • 总页数 158
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类 机械、仪表工业;
  • 关键词

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