Scholarlink

Purpose <p>In labyrinth seal-rotor systems, the nonlinear excitation induced by sealing forces alters the load distribution within rolling bearings, which increases the likelihood of local defects.&#xa0;This study investigates the nonlinear dynamic behaviors induced by local defects in a labyrinth seal-rotor system.</p> Methods <p>A system dynamics model is established using the finite element method, the lumped mass method, and the Muszynska sealing force model. Nonlinear bearing force models are derived based on Hertz contact theory to characterize three types of local defects:&#xa0;outer raceway local defects, inner raceway local defects, and coupled inner and outer raceway defects.</p> Results <p>Both slight single defects and coupled defects cause the appearance of super-harmonics and subharmonics (1/2X, 3/2X), while coupled defects also excite additional subharmonics (5/2X, 1/5X, 4/5X). As the defect range angle increases, subharmonics become more abundant in the presence of inner raceway defects and coupled defects. However, severe outer raceway defects and coupled defects cause airflow excitation to occur 100 r/min earlier. Bearing clearance is negatively correlated with the instability speed. Moreover, excessively small bearing clearance tends to amplify the vibration amplitude before instability occurs. Outer raceway defects exhibit high sensitivity to unbalanced force vector orientation angle variations, with amplitude patterns similar to healthy states and governed by rotational speed. Conversely, Inner raceway and coupled defects exhibit significantly reduced sensitivity to angle variations, manifesting smaller amplitude fluctuations.</p> Conclusions <p>Local defects significantly affect the vibration characteristics in the range of low to medium speed. Inner raceway defects and coupled defects excite more subharmonic components, whereas outer raceway defects and coupled defects cause the system to become unstable earlier. After instability occurs, the airflow excitation masks the bearing fault characteristics. A proper reduction in bearing clearance can suppress unstable vibrations caused by local bearing defects and increase the system instability speed. Optimal adjustment of the unbalanced force vector orientation angle according to operating speed reduces system amplitude and suppresses unstable vibration induced by outer raceway defects<b>.</b> Inner raceway and coupled defects partially diminish this vibration reduction effect.</p>

错误：搜索内容不能为空，请输入英文关键词
错误：关键词超出字数限制，请精简
高级检索

Nonlinear Dynamic Behaviors of Labyrinth Seal-Rotor System with Local Defects in Rolling Bearings

  • 期刊论文

  • 发表日期：

    2025年9月6日

查看全文
  • Yuegang Luo,
  • Ning Liu,
  • Songsong Xiao,
  • Yunteng Han,
  • Zixuan Li

摘要

Purpose

In labyrinth seal-rotor systems, the nonlinear excitation induced by sealing forces alters the load distribution within rolling bearings, which increases the likelihood of local defects. This study investigates the nonlinear dynamic behaviors induced by local defects in a labyrinth seal-rotor system.

Methods

A system dynamics model is established using the finite element method, the lumped mass method, and the Muszynska sealing force model. Nonlinear bearing force models are derived based on Hertz contact theory to characterize three types of local defects: outer raceway local defects, inner raceway local defects, and coupled inner and outer raceway defects.

Results

Both slight single defects and coupled defects cause the appearance of super-harmonics and subharmonics (1/2X, 3/2X), while coupled defects also excite additional subharmonics (5/2X, 1/5X, 4/5X). As the defect range angle increases, subharmonics become more abundant in the presence of inner raceway defects and coupled defects. However, severe outer raceway defects and coupled defects cause airflow excitation to occur 100 r/min earlier. Bearing clearance is negatively correlated with the instability speed. Moreover, excessively small bearing clearance tends to amplify the vibration amplitude before instability occurs. Outer raceway defects exhibit high sensitivity to unbalanced force vector orientation angle variations, with amplitude patterns similar to healthy states and governed by rotational speed. Conversely, Inner raceway and coupled defects exhibit significantly reduced sensitivity to angle variations, manifesting smaller amplitude fluctuations.

Conclusions

Local defects significantly affect the vibration characteristics in the range of low to medium speed. Inner raceway defects and coupled defects excite more subharmonic components, whereas outer raceway defects and coupled defects cause the system to become unstable earlier. After instability occurs, the airflow excitation masks the bearing fault characteristics. A proper reduction in bearing clearance can suppress unstable vibrations caused by local bearing defects and increase the system instability speed. Optimal adjustment of the unbalanced force vector orientation angle according to operating speed reduces system amplitude and suppresses unstable vibration induced by outer raceway defects. Inner raceway and coupled defects partially diminish this vibration reduction effect.