An analysis method of pressure characteristic for cylindrical intershaft gas film seal considering centrifugal expansion, rotor misalignment, and precession

Guo-qiang, Hou; Su, Hua; Huang, Yuhui; Chen, Congcong

doi:10.1177/13506501211039793

Cited by 5 publications

(5 citation statements)

References 19 publications

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“…As is well known, inter-shaft rub-impact faults between rotors can lead to a reverse whirl of the rotor. Kang et al [17] found in their study that reverse whirl caused by rotor-stator rub impact includes not only frequency components due to unbalanced excitation but also significantly large negative reverse whirl frequencies. However, in this study, the inter-shaft rub-impact excitation does not directly act on the disk position.…”

Section: Analysis Of Whirl Behavior In Dual-rotor Systems With Inter-...mentioning

confidence: 99%

“…The full-spectrum method was first proposed by Bently. For a detailed introduction to the theory and derivation process of the full-spectrum method, please refer to [17].…”

Section: Analysis Of Inter-shaft Rub-impact Fault Whirl Behavior Base...mentioning

confidence: 99%

“…The above are all studies on rub-impact faults between rotors and stators. In dual-rotor aircraft engines, gas leakage is one of the key factors contributing to efficiency loss [17]. To avoid such problems when both rotors are operating in tandem, the gap between the two rotors is typically sealed [18].…”

Section: Introductionmentioning

confidence: 99%

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Analysis of Nonlinear Vibration Characteristics and Whirl Behavior of Dual-Rotor Systems with Inter-Shaft Rub Impact

Wang,

Sun,

Liu

et al. 2024

Mathematics

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Previous studies on rub-impact faults have mainly focused on the rub-impact between rotors and stators, with less research on inter-rotor rub impact. The impact of inter-rotor rub impact on rotor nonlinear vibration is particularly significant. This study investigates the effects of inter-shaft rub impact on the vibration characteristics and whirl behavior of dual-rotor systems. Initially, a dual-rotor model with inter-shaft bearings is established using the finite element method, and inter-shaft rub-impact forces are derived based on contact mechanics. Next, the system response is solved using the Newmark method. Vibration characteristics are analyzed through Campbell diagrams, 3D waterfall plots, time-frequency domain plots, and steady-state rub-impact force plots. Finally, the influence of inter-shaft rub impact on the whirl behavior of the dual-rotor system is studied based on the theory of full-spectrum analysis. The study concludes that inter-shaft rub-impact faults shift the system’s resonance points backward, increase harmonic and combination frequency components, and significantly affect the system response under dual-rotor co-rotation. Excessive friction can lead to self-excited vibrations and sudden amplitude increases, particularly in the LP rotor frequency. Additionally, inter-shaft rub impact primarily affects the whirl behavior of the LP-compressor disk1, showing multiple cycles of forward and backward whirl alternation during acceleration due to combined unbalanced and rub-impact excitations.

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Section: Analysis Of Whirl Behavior In Dual-rotor Systems With Inter-...mentioning

confidence: 99%

“…The full-spectrum method was first proposed by Bently. For a detailed introduction to the theory and derivation process of the full-spectrum method, please refer to [17].…”

Section: Analysis Of Inter-shaft Rub-impact Fault Whirl Behavior Base...mentioning

confidence: 99%

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Analysis of Nonlinear Vibration Characteristics and Whirl Behavior of Dual-Rotor Systems with Inter-Shaft Rub Impact

Wang,

Sun,

Liu

et al. 2024

Mathematics

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“…Hou et al analyzed the impact of rotor eccentricity and centrifugal expansion effect on the performance of a compliant cylindrical intershaft gas film seal and proposed an analysis method for gas film pressure. However, in the study of operating parameters, the impact of eccentricity and rotational speed on sealing performance was mainly considered [23,24]. Wang et al designed a groove bottom diversion texture and studied the influence of diversion texture on the sealing performance of cylindrical gas film seals under different working conditions.…”

Section: Introductionmentioning

confidence: 99%

Research on Micro Gap Flow Field Characteristics of Cylindrical Gas Film Seals Based on Experimental and Numerical Simulation

Xu,

Sun

et al. 2023

Aerospace

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Flexible support cylindrical gas film seals (CGFSs) adapt well to rotor whirling and have a good gas lubrication effect during thermal deformation. However, when a CGFS operates under the “three high” (high interface slip speed, high-pressure differential, and high ambient temperature) operating conditions, the complex deformation of the support structure is a crucial factor affecting the stability of the CGFS. A thorough and systematic analysis of the micro gap flow field characteristics of flexible support CGFSs is a fundamental problem when we study the deformation of the support structure under multiple physical field conditions. This study uses a cylindrical gas film high-speed rotor test rig to study and compare the sealing characteristics of experiments and numerical simulations and then optimizes and verifies the accuracy and effectiveness of the simulation model. A cross-scale gas film grid model is used to analyze the flow field characteristics and seal ability of different groove models and compare the mechanical characteristics and sealing performance. We also analyze the gas film pressure distribution in micro gaps and explore the impact of dynamic pressure groove microstructure on flow field characteristics. Results show that micro gaps are the primary conditions for generating hydrodynamic effects, and high rotational speed, high-pressure differential, and large eccentricity have a significant effect on improving hydrodynamic effects and enhancing gas film stability. However, an increase in these parameters can cause an increase in leakage rate. A single flow channel makes it easier to improve the hydrodynamic effect, gas film load-bearing ability, and gas film stability while reducing leakage rate. The analyses in this study supplement and improve the theory of the flow field characteristics of cylindrical annular micro gaps and provide a theoretical basis for exploring the relation between the support structural parameters of the CGFS and the mechanical characteristics of the micro gap flow field. This study provides important guidance to the establishment of a quantitative design theory of supporting structures.

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“…In order to solve the problem of inter-shaft sealing end face collision caused by large axial displacement of the rotor, cylindrical gas film technology has been proposed for reverse inter-shaft sealing. Hou et al [15,16] proposed a cylindrical reverse inter-shaft gas film seal with an elastic support structure and used an aeroelastic coupling calculation method to analyze the effects of rotor rotation direction, seal ring width, rotor speed, and rotor radius on sealing performance. However, the cylindrical reverse inter-shaft sealing structure of the elastic support structure is complex, making it difficult to process, install, and adjust.…”

Section: Introductionmentioning

confidence: 99%

Performance Analysis of the C/C Composite Cylindrical Reverse Inter-Shaft Gas Film Seal

Zhao

Yang

2023

Lubricants

Self Cite

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The reverse inter-shaft gas film seal is a gas path seal used in the intermediate bearing cavity of an aero-engine, which is challenging to implement due to its special installation and usage conditions. This paper proposes a C/C (Carbon/Carbon) composite cylindrical reverse inter-shaft seal structure and carries out a performance simulation analysis based on bidirectional fluid–solid coupling technology. The results show that the cylindrical reverse inter-shaft gas film seal with double-layer C/C composite sealing rings with different material mesoscopic parameters can balance seal leakage and friction power consumption and is beneficial to improving the comprehensive performance of the seal. As the mesoscopic parameters of the inner sealing ring material increase in warp and weft density, the sealing leakage rate decreases, and the gas film force and gas friction power consumption all increase. As the pressure difference increases, the sealing leakage rate and gas film force increase. As the rotation speed of the inner and outer rotors increases, the seal leakage rate increases, and the gas film force decreases. A C/C composite sealing ring cylindrical reverse inter-shaft gas film seal has a lower leakage rate and larger gas film force than a graphite sealing ring cylindrical reverse inter-shaft seal, which confers certain performance advantages. The work in this paper can provide a reference for the design of reverse inter-shaft seals.

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An analysis method of pressure characteristic for cylindrical intershaft gas film seal considering centrifugal expansion, rotor misalignment, and precession

Cited by 5 publications

References 19 publications

Analysis of Nonlinear Vibration Characteristics and Whirl Behavior of Dual-Rotor Systems with Inter-Shaft Rub Impact

Analysis of Nonlinear Vibration Characteristics and Whirl Behavior of Dual-Rotor Systems with Inter-Shaft Rub Impact

Research on Micro Gap Flow Field Characteristics of Cylindrical Gas Film Seals Based on Experimental and Numerical Simulation

Performance Analysis of the C/C Composite Cylindrical Reverse Inter-Shaft Gas Film Seal

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