The Acoustic Influence of Cell Depth on the Rotordynamic Characteristics of Smooth-Rotor/Honeycomb-Stator Annular Gas Seals
The Acoustic Influence of Cell Depth on the Rotordynamic Characteristics of Smooth-Rotor/Honeycomb-Stator Annular Gas Seals
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DOI：
10.1115/1.2817079
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发表时间：
1996-06
影响因子：
1.5
通讯作者：
G. Kleynhans;D. Childs
中科院分区：
文献类型：
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作者：
G. Kleynhans;D. Childs
蜂窝定子/光滑转子密封采用双控制体积模型，传统的控制体积用于通流和蜂窝单元的电容蓄能器模型。蜂窝状单元的控制体积被示出为引起主流的有效声速的急剧减少，将最低的声学频率降到转子动力学的感兴趣的频率范围内。在这些情况下，密封件的阻抗函数不能用常规的（与频率无关的）刚度、阻尼和质量系数来建模。需要更一般的转换函数来考虑反作用力，这里计算的传递函数是直接力函数的超前-滞后项和交叉耦合函数的滞后项。实验测量验证了所提出的传递函数的幅度和相位趋势。与磁轴承或基础的传递函数相比，这些一阶函数是简单的。对于由于不平衡引起的同步响应，它们可以近似为传统转子动力学代码中与运行速度相关的刚度和阻尼系数。稳定性和瞬态响应的正确预测将需要更通用的算法，大概使用状态空间格式。
A two-control-volume model is employed for honeycomb-stator/smooth-rotor seals, with a conventional control-volume used for the throughflow and a capacitance-accumulator model for the honeycomb cells. The control volume for the honeycomb cells is shown to cause a dramatic reduction in the effective acoustic velocity of the main flow, dropping the lowest acoustic frequency into the frequency range of interest for rotordynamics. In these circumstances, the impedance functions for the seals cannot be modeled with conventional (frequency-independent) stiffness, damping, and mass coefficients. More general transform functions are required to account for the reaction forces, and the transfer functions calculated here are a lead-lag term for the direct force function and a lag term for the cross-coupled function. Experimental measurements verify the magnitude and phase trends of the proposed transfer functions. These first-order functions are simple, compared to transfer functions for magnetic bearings or foundations. For synchronous response due to imbalance, they can be approximated by running-speed-dependent stiffness and damping coefficients in conventional rotordynamics codes. Correct predictions for stability and transient response will require more general algorithms, presumably using a state-space format.