Analysis of leakage characteristics and structural optimization of two-stage floating ring seal

Tingxun Hu; Wangqun Deng; Zhenhuan Tang; Dong Mi; Weifeng Zhang; Xiaoyan Wang

doi:10.1515/tjj-2025-0021

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Analysis of leakage characteristics and structural optimization of two-stage floating ring seal

Tingxun Hu , Wangqun Deng , Zhenhuan Tang , Dong Mi , Weifeng Zhang und Xiaoyan Wang

Veröffentlicht/Copyright: 19. März 2025

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Aus der Zeitschrift International Journal of Turbo & Jet-Engines Band 42 Heft 3

Abstract

Two-stage floating ring seal is a non-contact circumferential seal with low leakage and high reliability. This paper elaborates on the variation mechanism and calculation method of the working clearance and working conditions of sealing chamber, reveals the corresponding relationship between operating conditions of aircraft engine and leakage characteristics of two-stage floating ring seal, obtains an effective method for analyzing the leakage characteristics of two-stage floating ring seals. The pressure of sealing chamber can be determined by continuously assuming the pressure of sealing chamber and substituting it to continuity equation. Carry out leakage characteristic experiments under specific operating conditions, the minimum deviation between the value of calculation and the experimental results is −11.47 %, the maximum deviation is 7.34 %, and the average of the absolute value of deviation is 5.01 %. The optimization design scheme for the working clearance and the intermediate air flow channel have been proposed, which can provide important support for improving the reliability and sealing performance of the two-stage floating ring seal.

Keywords: two-stage floating ring seal; leakage characteristic; working clearance; sealing chamber; experiment

Corresponding author: Wangqun Deng, AECC Hunan Aviation Powerplant Research Institute, Zhuzhou, Hunan 412002, China; and Key Laboratory of Aero-Engine Vibration Technology, Aero Engine Corporation of China, Zhuzhou 412002, China, E-mail: hnzzdwq@163.com

Nomenclature (SI units)

T _f: temperature of the sealing gas (K)
T _z: temperature of the bearing cavity (K)
T _p: temperature of the rotating ring (K)
K _f: convective heat transfer coefficients of the sealing gas (W·m²/K)
K _z: convective heat transfer coefficients of the bearing cavity (W·m²/K)
δ _p0: thermal expansion of the rotating ring (m)
a: linear expansion coefficient of the rotating rin (/K)
r _p: initial size of the outer diameter of rotating ring (m)
T s: room temperature (K)
δ _z: actual magnitude of interference (m)
δ _c: initial magnitude of interference (m)
α _w: linear expansion coefficient of the outer ring (/K)
α _s: linear expansion coefficient of the graphite ring (/K)
∆ T: temperature difference (K)
d ₁: inner diameter of the graphite ring (m)
d ₁: inner diameter of the outer ring (m)
d ₃: outer diameter of the outer ring (m)
L 1: width of the graphite ring (m)
L 2: width of the outer ring (m)
L: contact width between the graphite ring and the outer ring (m)
p 0: pressure on the graphite ring and the outer ring (N)
p 1: equivalent pressure on the graphite ring (N)
p 2: equivalent pressure on the outer ring (N)
K ₁: diameter ratio of the graphite ring
K ₂: diameter ratio of the outer ring
σ _r1: equivalent circumferential stress of the graphite ring (Pa)
σ _θ1: equivalent radial stress of the graphite ring (Pa)
σ _z1: equivalent axial stress of the graphite ring (Pa)
σ _r2: equivalent circumferential stress of the outer ring (Pa)
σ _θ2: equivalent radial stress of the outer ring (Pa)
σ _z2: equivalent axial stress of the outer ring (Pa)
E ₁: elastic modulus of the graphite ring (Pa)
μ ₁: Poisson’s ratio of the graphite ring
E ₂: elastic modulus of the outer ring (Pa)
μ ₂: Poisson’s ratio of the outer ring
∆ r 1: radial displacement of the graphite ring (m)
∆ r 2: radial displacement of the outer ring (m)
P 0: pressure in the sealing chamber (Pa)
S 1: leakage from the high-pressure side (g/s)
S 2: leakage from the middle bleed side (g/s)
T 1: temperature on the high-pressure side (K)
T 2: temperature on the middle bleed side (K)

Research ethics: Not applicable.
Informed consent: Informed consent was obtained from all individuals included in this study, or their legal guardians or wards.
Author contributions: All authors have accepted responsibility for the entire content of this manuscript and approved its submission.
Use of Large Language Models, AI and Machine Learning Tools: None declared.
Conflict of interest: The authors state no conflict of interest.
Research funding: This study is supported by the Technology Innovation Platform Foundation of AECC (No. CXPT-2023-023), and the National Natural Science Foundation of China (No.52375077).
Data availability: Not applicable.

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Received: 2025-02-23

Accepted: 2025-02-23

Published Online: 2025-03-19

Published in Print: 2025-08-26

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https://doi.org/10.1515/tjj-2025-0021

Schlagwörter für diesen Artikel

two-stage floating ring seal; leakage characteristic; working clearance; sealing chamber; experiment