Improvements in honeycomb abradable seals

Potter, D.J.; Chai, Yaw Wang; Tatlock, G. J.

doi:10.3184/096034009x464302

Cited by 9 publications

(4 citation statements)

References 2 publications

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“…Such situations normally see nickel superalloy face sheets and honeycomb cores, which can be brazed with conventional nickel alloys (e.g. ISO 17972-Ni620 [167,178,179] or ISO 17972-Ni650 [176]; ISO 17972-Ni620 can also join stainless steels [180]). Mobile species in nickel brazing can however lead to problematic erosion (which is described in [177]).…”

Section: Alloys For Small Contact Area Jointsmentioning

confidence: 99%

“…As well, erosion (dissolution of the parent metal to a high degree) must be considered. Brazed honeycomb sandwich panels may be encountered in thermal protection in reusable space launch vehicle designs, such as the NASA X-33 vehicle [175], abradable seals in jet engines [176] or in catalytic converters [177]. Such situations normally see nickel superalloy face sheets and honeycomb cores, which can be brazed with conventional nickel alloys (e.g.…”

Section: Alloys For Small Contact Area Jointsmentioning

confidence: 99%

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Brazing filler metals

Way

Willingham

Goodall

2019

International Materials Reviews

101

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Brazing is a 5000-year-old joining process which still meets advanced joining challenges today. In brazing, components are joined by heating above the melting point of a filler metal placed between them; on solidification a joint is formed. It provides unique advantages over other joining methods, including the ability to join dissimilar material combinations (including metal-ceramic joints), with limited microstructural evolution; producing joints of relatively high strength which are often electrically and thermally conductive. Current interest in brazing is widespread with filler metal development key to enabling a range of future technologies including; fusion energy, Solid Oxide Fuel Cells and nanoelectronics, whilst also assisting the advancement of established fields, such as automotive lightweighting, by tackling the challenges associated with joining aluminium to steels. This review discusses the theory and practice of brazing, with particular reference to filler metals, and covers progress in, and opportunities for, advanced filler metal development.

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Section: Alloys For Small Contact Area Jointsmentioning

confidence: 99%

Section: Alloys For Small Contact Area Jointsmentioning

confidence: 99%

Brazing filler metals

Way

Willingham

Goodall

2019

International Materials Reviews

101

View full text Add to dashboard Cite

show abstract

“…Wear of the rotor is critical for the reliability of the sealing system and can have a negative effect on the leakage. In addition, abradable seal materials have to withstand thermal and corrosive environments [5]. They can be categorized into porous materials, low shear strength materials, and honeycomb structures [6].…”

Section: Introductionmentioning

confidence: 99%

Continued Experimental Study on the Friction Contact between a Labyrinth Seal Fin and a Honeycomb Stator: Slanted Position

et al. 2018

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Labyrinth seals are a state-of-the-art sealing technology to prevent and control leakage flows at rotor-stator interfaces in turbomachinery. Higher pressure ratios and the economical use of cooling air require small clearances, which lead to potential rubbing events. The use of honeycomb liners allows for minimal leakage by tolerating rub events to a certain extent. A previous study within an EU project investigated the complex contact conditions of honeycomb liners, with the idealized contact of a seal fin and a single parallel metal foil representing the honeycomb double foil section. In the present work, the results for the slanted foil position are shown and compared to the previous results. The variation of rub velocity, incursion speed, incursion rate, and seal geometry in a test rig allows for the identification of the influence on contact forces, temperatures, and wear. For the slanted position, significantly lower friction temperatures are observed, leading to a higher ratio of abrasive wear. Overall, the rub test results demonstrate strong interactions between the contact forces, friction temperatures, and wear.

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“…In another paper (He et al, 2012), conjugate heat transfer and windage heating in the stepped labyrinth with smooth and honeycomb lands were numerically investigated, and found that the presence of honeycomb cells increased the temperature gradient in the labyrinth fin and significantly decreased the temperature gradient in the stator. A honeycomb seal is an advanced seal structure with good abradability performance under conditions of high temperature and differential pressure (Wiebe, 1994;Potter et al, 2009). A honeycomb core is usually made from metal foils which are usually tens of microns thick, and then it is brazed on the skeleton at high temperature to form the outer ring.…”

Section: Introductionmentioning

confidence: 99%

Investigation of high-speed rubbing behavior of labyrinth-honeycomb seal for turbine engine application

Zhang

Guo³

et al. 2016

J. Zhejiang Univ. Sci. A

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Abstract:The labyrinth-honeycomb seal has been widely used in gas turbine engines as an abradable gas path seal to protect the rotor from wear and damage in rubbing interaction. It usually works with a stepped labyrinth because the knife-edged tips could produce a special dynamic sealing system, and then the minimum clearance is possible between the rotor and stationary component. To investigate the high-speed rubbing behavior between a Hastelloy-X honeycomb material and a GH4169 double stepped labyrinth, nine rubbing tests were conducted using a high-speed abrasion test rig while the blade tip speed varied from 150 to 450 m/s, and the incursion rate from 120 to 360 μm/s. The abradability of honeycomb made from Hastelloy-X was fully verified by analyzing the visual rubbing observations, rubbing forces, and impact acceleration. It is shown that compression deformation happens to the honeycomb material during the rubbing process with the labyrinth blade except for a simple cutting mechanism, which is mainly affected by the parameter of incursion rate. Thermal ablation and oxidation were the main damage occurring on the labyrinth tip and appeared more obviously at a higher blade tip speed. Rubbing forces and impact acceleration were obtained from a piezoelectric dynamometer and acceleration sensor during the rubbing process. At a blade tip speed of 300 m/s and incursion rate of 360 μm/s, radial and tangential forces show their maximum values of 716 N and 871 N, respectively. The peak value of acceleration presents 341g with the highest blade tip speed of 450 m/s and the highest incursion rate of 360 μm/s. All testing results provide a great deal of effective information on high-speed rubbing behavior for the abradablility evaluation of a honeycomb.

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Improvements in honeycomb abradable seals

Cited by 9 publications

References 2 publications

Brazing filler metals

Brazing filler metals

Continued Experimental Study on the Friction Contact between a Labyrinth Seal Fin and a Honeycomb Stator: Slanted Position

Investigation of high-speed rubbing behavior of labyrinth-honeycomb seal for turbine engine application

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