Brush seals in industrial gas turbines

Wolfe, Chris; Chiu, Ryan; Cromer, R.; Crum, G.; Marks, Paul; Stuck, A.; Turnquist, Norman; Reluzco, G.; Dinç, O. S.

doi:10.2514/6.1997-2730

Cited by 14 publications

(5 citation statements)

References 1 publication

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“…Application of brush seals in turbomachinery offers a significant performance benefit over traditional labyrinth seals due to reduced secondary leakage flow [1,2]. Since the early 1990s, there has been significant brush seal research and development work at General Electric for steam turbine, gas turbine and aircraft engine applications.…”

Section: Introductionmentioning

confidence: 99%

Rotating Brush Seal

Zheng¹,

Mack²,

Trivedi³

et al. 2014

50th AIAA/ASME/SAE/ASEE Joint Propulsion Conference

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Brush seals have been widely used in gas turbine, steam turbine and aviation engines because of their superior sealing effectiveness over labyrinth seal. Brush seals are usually mounted on the stationary part, only the flexible bristle tips engage a rotating part to form a dynamic seal. In this paper, configuration enhancement and prototype demonstration are carried out to study a brush seal that is attached to a rotating shaft. To achieve seal flexibility, the bristles are no longer angled circumferentially. Instead, they are angled axially and supported by a conical backplate. Under rotation, the bristles are pressed to the backplate by centrifugal force. The pressure loading can be either on the bristles side to further load the bristles against the backplate, or on the backplate side to unload the centrifugal force. The benefits of rotating brush seal include no direct rub on rotor that reduces heating to rotor and has less impact on rotor instability. Seal configurations are tailored to fit into interstage and inter-shaft locations in turbomachines.In the second portion of the paper, the manufacture process to produce a compact rotating brush seal is described. Finally, a modeling approach for predicting stiffness and operating stresses in these seals is outlined.

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Section: Introductionmentioning

confidence: 99%

Rotating Brush Seal

Zheng¹,

Mack²,

Trivedi³

et al. 2014

50th AIAA/ASME/SAE/ASEE Joint Propulsion Conference

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“…Therefore, almost all wear occurs during transient conditions. 17 Neef et al 20 conducted a wear test on a steam turbine brush seal and presented a correlation for wear calculation. Generally, the purpose of brush seal design is to have enough stiffness to support the bristle pack against the pressure drop while having minimum wear during interference operation.…”

Section: Introductionmentioning

confidence: 99%

“…Results show that the brush seal installed downstream of the diaphragm leads to less leakage flow which is also demonstrated by Kirk et al 18 The experience of brush seal development at GE is documented in. 4,15,17,30 Installation of brush seal in different locations of GE gas turbines and corresponding benefits are reported in. 4 This study aims to improve the power of a three-stage gas turbine.…”

Section: Introductionmentioning

confidence: 99%

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Brush seal design and secondary air system modification of a heavy-duty gas turbine to improve the output power

Amini

Khavari

Alizadeh

2022

Proceedings of the Institution of Mechanical Engineers, Part A:

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The overall performance of heavy-duty gas turbines is strongly affected by the mass flow distribution of the secondary air system. Reducing the mass flow of the secondary air is a remarkable method to improve the performance of a gas turbine. The aim of this article is to implement a brush seal as an alternative to labyrinth seal. Based on the experiences gained from the integrity of brush seals into a gas turbine, installing a brush seal would not necessarily improve turbine performance. This is because of SAS mass flow redistribution, which may not lead to overall SAS mass flow reduction. Therefore, some other components in the SAS arrangement should be modified as controlling variables to overcome this problem. The effect of these modifications on the airflow distribution is investigated using an in-house network analysis code. To establish an optimum solution (optimized brush seal geometry and controlling variables), the network analysis code is coupled with an in-house optimization code that benefits from the Genetic Algorithms and Artificial Neural Networks. Some constraints including upstream and downstream cavity purge flow and vane cooling air are considered in the optimization process. The final network results show a 33.27% reduction in overall SAS mass flow. To ensure an improvement in the performance of the new three-stage turbine, a CFD analysis is conducted, which indicates 1.0% more power with respect to the original turbine. In the end, the aerodynamic and mechanical behavior of the brush seal is analyzed using CFD and FEM.

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“…Over the years, a large amount of information has been gathered on the long-term behaviour of brush seals as part of maintenance work and regular checks on the condition of the seals. Publications [1][2][3][4][5][6] provide examples of this in extracts. The focus in assessing the seals was primarily on the wear condition and the change in leakage rates over time.…”

Section: Introductionmentioning

confidence: 99%

Contamination of Brush Seals by Oil and Salt and Its Impact on Rubbing and Hysteresis Behaviour

Hildebrandt¹,

Schwitzke²,

Bauer³

2019

IJTPP

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The literature already contains some experimental, analytical and numerical investigations on the rubbing and hysteresis behaviour of brush seals. What the investigations have in common is that they were carried out with new and uncontaminated seals, or that such a condition was assumed. The influence of contamination has not been explicitly investigated yet. Particularly in stationary gas and steam turbines, foreign substances can accumulate on and in the bristle package during steady-state operation. In the case of a rubbing event with a contaminated brush seal, e.g., during shutdown of the machine, the process is not expected to be comparable to that assumed in the presence of a new, uncontaminated seal. The present paper is dedicated to the question of the influence of contamination on the total frictional power loss generated during rubbing and the distribution of heat fluxes in friction contact. For this purpose, rub tests with two seals were carried out on the brush seal test rig of the Institute of Thermal Turbomachinery (ITS) in new conditions. Subsequently, the sealing packages were contaminated with oil or a salt mixture. After the treatment, the rub tests were repeated and compared with the previous tests. In addition, stiffness measurements were used to assess the degree of contamination. A strong influence on the rubbing behaviour by the contamination was detected. Contamination causes the flexibility of the bristle package to be greatly reduced. As a result, especially at the beginning of the first measurements, the total power losses and rotor heat inputs are strongly increased. This flexibility is partly regained in the course of the measurements. As expected, contamination also influences the hysteresis behaviour of the seal. A highly increased leakage rate after rubbing could be observed, because the bristles remained close to their deflected positions. In the case of the salted seal, however, an improvement in the leakage performance could be observed after several repeat tests.

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Brush seals in industrial gas turbines

Cited by 14 publications

References 1 publication

Rotating Brush Seal

Rotating Brush Seal

Brush seal design and secondary air system modification of a heavy-duty gas turbine to improve the output power

Contamination of Brush Seals by Oil and Salt and Its Impact on Rubbing and Hysteresis Behaviour

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