Use of pressure measurements to determine effectiveness of turbine rim seals

Research output: Contribution to journalArticle

9 Citations (Scopus)

Abstract

The ingress of hot gas through the rim seal of a gas turbine depends on the pressure difference between the mainstream flow in the turbine annulus and that in the wheel-space radially inward of the rim seal. In this paper, a previously published orifice model is modified so that the sealing effectiveness εc determined from concentration measurements in a rig could be used to determine εp, the effectiveness determined from pressure measurements in an engine. It is assumed that there is a hypothetical “sweet spot” on the vane platform where the measured pressures would ensure that the calculated value of εp equals εc, the value determined from concentration measurements. Experimental measurements for a radial-clearance seal show that, as predicted, the hypothetical pressure difference at the sweet spot is linearly related to the pressure difference measured at an arbitrary location on the vane platform. There is good agreement between the values of εp determined using the theoretical model and values of εc determined from concentration measurements. Supporting computations, using a 3D steady computational fluid dynamics (CFD) code, show that the axial location of the sweet spot is very close to the upstream edge of the seal clearance. It is shown how parameters obtained from measurements of pressure and concentration in a rig could, in principle, be used to calculate the sealing effectiveness in an engine.
Original languageEnglish
Article number032510
Pages (from-to)1-10
Number of pages10
JournalJournal of Engineering for Gas Turbines and Power: Transactions of the ASME
Volume137
Issue number3
Early online date7 Oct 2014
DOIs
Publication statusPublished - 1 Mar 2015

Fingerprint

Pressure measurement
Seals
Turbines
Engines
Orifices
Gas turbines
Wheels
Computational fluid dynamics
Gases

Cite this

@article{fe9965754e4d4c98a7f4c4f73ce9ec8e,
title = "Use of pressure measurements to determine effectiveness of turbine rim seals",
abstract = "The ingress of hot gas through the rim seal of a gas turbine depends on the pressure difference between the mainstream flow in the turbine annulus and that in the wheel-space radially inward of the rim seal. In this paper, a previously published orifice model is modified so that the sealing effectiveness εc determined from concentration measurements in a rig could be used to determine εp, the effectiveness determined from pressure measurements in an engine. It is assumed that there is a hypothetical “sweet spot” on the vane platform where the measured pressures would ensure that the calculated value of εp equals εc, the value determined from concentration measurements. Experimental measurements for a radial-clearance seal show that, as predicted, the hypothetical pressure difference at the sweet spot is linearly related to the pressure difference measured at an arbitrary location on the vane platform. There is good agreement between the values of εp determined using the theoretical model and values of εc determined from concentration measurements. Supporting computations, using a 3D steady computational fluid dynamics (CFD) code, show that the axial location of the sweet spot is very close to the upstream edge of the seal clearance. It is shown how parameters obtained from measurements of pressure and concentration in a rig could, in principle, be used to calculate the sealing effectiveness in an engine.",
author = "Owen, {J M} and K Wu and Scobie, {J A} and Sangan, {C M} and G Cho and Lock, {G D}",
year = "2015",
month = "3",
day = "1",
doi = "10.1115/1.4028395",
language = "English",
volume = "137",
pages = "1--10",
journal = "Journal of Engineering for Gas Turbines and Power: Transactions of the ASME",
issn = "0742-4795",
publisher = "American Society of Mechanical Engineers (ASME)",
number = "3",

}

TY - JOUR

T1 - Use of pressure measurements to determine effectiveness of turbine rim seals

AU - Owen, J M

AU - Wu, K

AU - Scobie, J A

AU - Sangan, C M

AU - Cho, G

AU - Lock, G D

PY - 2015/3/1

Y1 - 2015/3/1

N2 - The ingress of hot gas through the rim seal of a gas turbine depends on the pressure difference between the mainstream flow in the turbine annulus and that in the wheel-space radially inward of the rim seal. In this paper, a previously published orifice model is modified so that the sealing effectiveness εc determined from concentration measurements in a rig could be used to determine εp, the effectiveness determined from pressure measurements in an engine. It is assumed that there is a hypothetical “sweet spot” on the vane platform where the measured pressures would ensure that the calculated value of εp equals εc, the value determined from concentration measurements. Experimental measurements for a radial-clearance seal show that, as predicted, the hypothetical pressure difference at the sweet spot is linearly related to the pressure difference measured at an arbitrary location on the vane platform. There is good agreement between the values of εp determined using the theoretical model and values of εc determined from concentration measurements. Supporting computations, using a 3D steady computational fluid dynamics (CFD) code, show that the axial location of the sweet spot is very close to the upstream edge of the seal clearance. It is shown how parameters obtained from measurements of pressure and concentration in a rig could, in principle, be used to calculate the sealing effectiveness in an engine.

AB - The ingress of hot gas through the rim seal of a gas turbine depends on the pressure difference between the mainstream flow in the turbine annulus and that in the wheel-space radially inward of the rim seal. In this paper, a previously published orifice model is modified so that the sealing effectiveness εc determined from concentration measurements in a rig could be used to determine εp, the effectiveness determined from pressure measurements in an engine. It is assumed that there is a hypothetical “sweet spot” on the vane platform where the measured pressures would ensure that the calculated value of εp equals εc, the value determined from concentration measurements. Experimental measurements for a radial-clearance seal show that, as predicted, the hypothetical pressure difference at the sweet spot is linearly related to the pressure difference measured at an arbitrary location on the vane platform. There is good agreement between the values of εp determined using the theoretical model and values of εc determined from concentration measurements. Supporting computations, using a 3D steady computational fluid dynamics (CFD) code, show that the axial location of the sweet spot is very close to the upstream edge of the seal clearance. It is shown how parameters obtained from measurements of pressure and concentration in a rig could, in principle, be used to calculate the sealing effectiveness in an engine.

U2 - 10.1115/1.4028395

DO - 10.1115/1.4028395

M3 - Article

VL - 137

SP - 1

EP - 10

JO - Journal of Engineering for Gas Turbines and Power: Transactions of the ASME

JF - Journal of Engineering for Gas Turbines and Power: Transactions of the ASME

SN - 0742-4795

IS - 3

M1 - 032510

ER -