Dynamic Characterization of an Adaptive Film-Riding Seal
Dynamic Characterization of an Adaptive Film-Riding Seal
复制标题
自适应薄膜骑行密封件的动态特性
DOI：
10.1115/1.4063549
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发表时间：
2024
期刊：
影响因子：
--
通讯作者：
Bird J
中科院分区：
文献类型：
--
作者：
Bird J
轴封控制叶轮机械内部旋转部件周围高压和低压区域之间的流体泄漏。静密封经常受到轴的损坏摩擦，这是由于装配不对中和运转过程中的旋转振动造成的。自适应密封旨在减少泄漏流量，同时最大限度地减少磨损。膜驱动压力驱动叶片式密封(FRPALS)就是这样一种设计，它利用了很大的安装间隙，并在压力下向轴方向吹下。本文提出了一种可用于自适应轴封设计和开发的数值模型，并用文献中的实验数据进行了验证。该模型使用修正的雷诺方程来预测液膜的动态、频率相关的刚度和阻尼系数。求出了不同工作间隙和压力差下的动态系数，生成了系数图。这些映射被结合到具有柔顺机械叶片的排气模型中，以预测当压力降增加时FRPALS的瞬时平移和角位移路径。将排污模型与从专门设计的轴封性能表征测试设备中收集的实验测量结果进行了比较。用涡流探头测量了FRPALS的位移轨迹，实验结果表明，该模型能够准确地预测密封在压差作用下的动态运动。
Shaft seals control the leakage of fluid between areas of high pressure and low pressure around rotating components inside turbomachinery. Static seals are often subject to damaging rubs with the shaft, caused by assembly misalignments and rotordynamic vibrations during operation. Adaptive seals aim to reduce leakage flows whilst minimizing wear. The film riding pressure actuated leaf seal (FRPALS) is one such design which utilizes a large installation clearance and is blown down toward the shaft under pressure. This paper presents a numerical model which can be used in the design and development of adaptive shaft seals, validated by experimental data from the literature. The model uses a modified version of the Reynolds equation to predict the dynamic, frequency-dependent stiffness and damping coefficients of the fluid film. The dynamic coefficients have been solved for different operational clearances and pressure differences to generate coefficient maps. These maps have been incorporated into a blow down model with compliant mechanical leaves to predict the transient translational and angular displacement paths of the FRPALS when subject to an increasing pressure drop. The blow down model has been compared against experimental measurements collected from a specially designed test facility for the characterization of shaft seal performance. Eddy current probes were used to measure the displacement paths of the FRPALS with the experimental values showing that the model can accurately predict the dynamic movement of the seal when subject to a pressure difference.