Fluid Dynamic Behavior of Conventional and Pressure Relieving Brush Seals

Bowen, Joshua P.; Bird, Joshua J.; Cross, Harry; Jenkins, Matthew R.; Bowsher, Aaron A.; Crudgington, Peter F.; Sangan, Carl M.; Scobie, James A.

doi:10.1115/1.4063775

Cited by 5 publications

(1 citation statement)

References 27 publications

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“…Manuel et al [3] studied the influence of fence heights on the stiffness, leakage rate, and friction loss of brush seals and concluded that the fence's height is essential for the brush seal. Bowen et al [4,5] constructed a large-scale brush seal to study flow characteristics and pressure distributions in the bristle pack, and the results can be used in the establishment of porous medium models. Markus [6] designed a test rig to study the friction heat of brush seals, and the test rig can measure the temperature can be used in the establishment of porous medium models.…”

Section: Introductionmentioning

confidence: 99%

Temperature Field and Performance Analysis of Brush Seals Based on FEA-CFD and the Porous Medium of Anisotropic Heat Transfer Models

Song,

Liu,

Sun

et al. 2023

Energies

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A brush seal is a type of contact sealing technology that generates a great amount of heat during operations. The heat can affect the seal’s performance and lifespan. To study the brush seals’ temperature distribution, a new model considering the anisotropic heat transfer effect is established in this paper. The friction heat effect at the bristles’ tip is studied. The temperature field and leakage rates are obtained by using combined finite element analysis (FEA)-computational fluid dynamics (CFD) analysis and the anisotropic heat transfer theory. The influence of operating and structural parameters on the temperature field and the sealing properties of the brush seal are investigated. It is shown that the value of the rotation rate and the interference can cause the temperature of the brush seal to increase. The pressure difference enhances the convective heat transfer from the brush seals. While the temperature at the bristles’ tip increases, the radial average temperature of the bristles decreases significantly. In the case of a small pressure difference, the fence’s height can increase the windward area, leading to stiff bristles and resulting in a temperature increase at the bristles’ tip; however, the effective flow area increases, resulting in an acceleration of the radial temperature’s decrease. To summarize, the porous medium model of anisotropic heat transfer provides a new method for studying brush seals, and it can reflect the temperature distribution and leakage performance of brush seals.

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Section: Introductionmentioning

confidence: 99%

Temperature Field and Performance Analysis of Brush Seals Based on FEA-CFD and the Porous Medium of Anisotropic Heat Transfer Models

Song,

Liu,

Sun

et al. 2023

Energies

View full text Add to dashboard Cite

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Tracking of Bristle Tip Deflections to Demonstrate Blow-Down in Brush Seals

Bowen,

Bowsher,

Crudgington

et al. 2024

Journal of Engineering for Gas Turbines and Power

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Sealing in gas turbines is paramount to overall performance and efficiency. Brush seals offer superior performance compared to other sealing solutions commonplace in modern turbomachinery. When subjected to a pressure load, a ring of flexible fine wire bristles – fitted at a lay angle to the radial plane – compact to resist the oncoming flow and deflect towards the rotor in a process known as blow-down. This study employs Digital Image Correlation to track individual bristle tips in three spatial axes throughout a large-scale brush seal test facility. This is the firsttime direct measurements of blow-down throughout the bristle pack have been presented, providing a unique insight into the mechanical behaviour of brush seals. Increased magnitudes of blow-down and axial bristle deflection were demonstrated in upstream bristle rows and at larger clearances. Analysis of these results in conjunction with the interrogation of the inter-bristle pressure field proved that blow-down is more prevalent for pressure relieving brush seals in comparison to conventional configurations. The reduction in the through-flow clearance area resulted in a significant enhancement in sealing performance for a clearance seal, highlighting a key advantage of the pressure relieving back plate design.

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Rotordynamics of a Single-Stage Brush Seal in Isolation: The Effects of Variable Stiffness and Back Plate Geometry

Bird,

Keogh,

Sangan

et al. 2024

Journal of Engineering for Gas Turbines and Power

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Brush seals control leakage around rotating components from areas of high to low pressure inside turbomachinery. They are known to contribute to the overall stability of gas turbines, therefore their dynamic behaviour is of particular importance to engine designers. Despite this, limited research exists in the literature on the rotordynamic behaviour of brush seals. This paper aims to experimentally characterise the leakage and rotordynamic performance of two seals with different bristle diameters tested with both conventional and pressure-relieved back plates with a slight interference. A dynamic test facility was utilised to study the dynamic characteristics of an isolated seal with changes in excitation frequency, rotational speed and pressure drop. Seal leakage increased with bristle diameter and with the use of the pressure-relieved back plate but reduced with increasing rotational speed for all tests. The direct dynamic coefficients were shown to increase with pressure difference. The back plate geometry influenced the change in stiffness coefficient with rotational speed. The larger bristle diameter resulted in a stiffer seal, however, the damping coefficient reduced with the reduction in packing density. The insight provided by these results will help inform engine manufacturers on the suitability of implementing brush seals in future gas turbine designs.

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Fluid Dynamic Behavior of Conventional and Pressure Relieving Brush Seals

Cited by 5 publications

References 27 publications

Temperature Field and Performance Analysis of Brush Seals Based on FEA-CFD and the Porous Medium of Anisotropic Heat Transfer Models

Temperature Field and Performance Analysis of Brush Seals Based on FEA-CFD and the Porous Medium of Anisotropic Heat Transfer Models

Tracking of Bristle Tip Deflections to Demonstrate Blow-Down in Brush Seals

Rotordynamics of a Single-Stage Brush Seal in Isolation: The Effects of Variable Stiffness and Back Plate Geometry

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