Prediction of ingress through turbine rim seals part 1

externally-induced ingress

J M Owen, Kunyuan Zhou, Mike Wilson, Oliver Pountney, Gary Lock

Research output: Chapter in Book/Report/Conference proceedingConference contribution

13 Citations (Scopus)

Abstract

Rotationally-induced (RI) ingress is caused by the negative pressure (relative to the external air) inside the wheelspace of a gas turbine; this negative pressure, which is created by the rotating flow in the wheel-space, drives the ingestion of hot gas through the rim seals. Externally-induced (EI) ingress is caused by the circumferential distribution of pressure created by the blades and vanes in the turbine annulus: ingress occurs in those regions where the external pressure is higher than that in the wheel-space, and egress occurs where it is lower. Although EI ingress is the dominant mechanism for hotgas ingestion in engines, there are some conditions in which RI ingress has an influence: this is referred to as combined ingress (CI). In Part 1 of this two-part paper, values of the sealing effectiveness (obtained using the incompressible orifice equations developed for EI ingress in an earlier paper) are compared with published experimental data and with results obtained using 3D steady compressible CFD (Computational Fluid Dynamics). Acceptable limits of the incompressible-flow assumption are quantified for the orifice model; for the CFD, even though the Mach number in the annulus reaches approximately 0.65, it is shown that the incompressible orifice equations are still valid. The results confirm that EI ingress is caused predominantly by the magnitude of the peak-to-trough circumferential difference of pressure in the annulus; the shape of the pressure distribution is of secondary importance for the prediction of ingress. A simple equation, derived from the orifice model, provides a very good correlation of the computed values of effectiveness. Using this correlation, it is possible to estimate the minimum sealing flow rate to prevent ingress without the need to know anything about the pressure distribution in the annulus; this makes the orifice model a powerful tool for rim-seal design.
Original languageEnglish
Title of host publicationASME Turbo Expo 2010: Power for Land, Sea, and Air, GT 2010
PublisherAmerican Society of Mechanical Engineers (ASME)
Pages1217-1234
Number of pages18
Volume4
Publication statusPublished - 2010
EventASME Turbo Expo 2010: Power for Land, Sea, and Air, GT 2010, June 14, 2010 - June 18, 2010 - Glasgow, UK United Kingdom
Duration: 1 Jan 2010 → …

Publication series

NameProceedings of the ASME Turbo Expo
PublisherAmerican Society of Mechanical Engineers

Conference

ConferenceASME Turbo Expo 2010: Power for Land, Sea, and Air, GT 2010, June 14, 2010 - June 18, 2010
CountryUK United Kingdom
CityGlasgow
Period1/01/10 → …

Fingerprint

Orifices
Seals
Turbines
Pressure distribution
Ingestion (engines)
Wheels
Computational fluid dynamics
Incompressible flow
Mach number
Turbomachine blades
Gas turbines
Flow rate
Engines
Air
Gases

Cite this

Owen, J. M., Zhou, K., Wilson, M., Pountney, O., & Lock, G. (2010). Prediction of ingress through turbine rim seals part 1: externally-induced ingress. In ASME Turbo Expo 2010: Power for Land, Sea, and Air, GT 2010 (Vol. 4, pp. 1217-1234). (Proceedings of the ASME Turbo Expo). American Society of Mechanical Engineers (ASME).

Prediction of ingress through turbine rim seals part 1 : externally-induced ingress. / Owen, J M; Zhou, Kunyuan; Wilson, Mike; Pountney, Oliver; Lock, Gary.

ASME Turbo Expo 2010: Power for Land, Sea, and Air, GT 2010. Vol. 4 American Society of Mechanical Engineers (ASME), 2010. p. 1217-1234 (Proceedings of the ASME Turbo Expo).

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Owen, JM, Zhou, K, Wilson, M, Pountney, O & Lock, G 2010, Prediction of ingress through turbine rim seals part 1: externally-induced ingress. in ASME Turbo Expo 2010: Power for Land, Sea, and Air, GT 2010. vol. 4, Proceedings of the ASME Turbo Expo, American Society of Mechanical Engineers (ASME), pp. 1217-1234, ASME Turbo Expo 2010: Power for Land, Sea, and Air, GT 2010, June 14, 2010 - June 18, 2010, Glasgow, UK United Kingdom, 1/01/10.
Owen JM, Zhou K, Wilson M, Pountney O, Lock G. Prediction of ingress through turbine rim seals part 1: externally-induced ingress. In ASME Turbo Expo 2010: Power for Land, Sea, and Air, GT 2010. Vol. 4. American Society of Mechanical Engineers (ASME). 2010. p. 1217-1234. (Proceedings of the ASME Turbo Expo).
Owen, J M ; Zhou, Kunyuan ; Wilson, Mike ; Pountney, Oliver ; Lock, Gary. / Prediction of ingress through turbine rim seals part 1 : externally-induced ingress. ASME Turbo Expo 2010: Power for Land, Sea, and Air, GT 2010. Vol. 4 American Society of Mechanical Engineers (ASME), 2010. pp. 1217-1234 (Proceedings of the ASME Turbo Expo).
@inproceedings{14aff4d1416546bbb1aec3cac54d6ae1,
title = "Prediction of ingress through turbine rim seals part 1: externally-induced ingress",
abstract = "Rotationally-induced (RI) ingress is caused by the negative pressure (relative to the external air) inside the wheelspace of a gas turbine; this negative pressure, which is created by the rotating flow in the wheel-space, drives the ingestion of hot gas through the rim seals. Externally-induced (EI) ingress is caused by the circumferential distribution of pressure created by the blades and vanes in the turbine annulus: ingress occurs in those regions where the external pressure is higher than that in the wheel-space, and egress occurs where it is lower. Although EI ingress is the dominant mechanism for hotgas ingestion in engines, there are some conditions in which RI ingress has an influence: this is referred to as combined ingress (CI). In Part 1 of this two-part paper, values of the sealing effectiveness (obtained using the incompressible orifice equations developed for EI ingress in an earlier paper) are compared with published experimental data and with results obtained using 3D steady compressible CFD (Computational Fluid Dynamics). Acceptable limits of the incompressible-flow assumption are quantified for the orifice model; for the CFD, even though the Mach number in the annulus reaches approximately 0.65, it is shown that the incompressible orifice equations are still valid. The results confirm that EI ingress is caused predominantly by the magnitude of the peak-to-trough circumferential difference of pressure in the annulus; the shape of the pressure distribution is of secondary importance for the prediction of ingress. A simple equation, derived from the orifice model, provides a very good correlation of the computed values of effectiveness. Using this correlation, it is possible to estimate the minimum sealing flow rate to prevent ingress without the need to know anything about the pressure distribution in the annulus; this makes the orifice model a powerful tool for rim-seal design.",
author = "Owen, {J M} and Kunyuan Zhou and Mike Wilson and Oliver Pountney and Gary Lock",
year = "2010",
language = "English",
volume = "4",
series = "Proceedings of the ASME Turbo Expo",
publisher = "American Society of Mechanical Engineers (ASME)",
pages = "1217--1234",
booktitle = "ASME Turbo Expo 2010: Power for Land, Sea, and Air, GT 2010",
address = "USA United States",

}

TY - GEN

T1 - Prediction of ingress through turbine rim seals part 1

T2 - externally-induced ingress

AU - Owen, J M

AU - Zhou, Kunyuan

AU - Wilson, Mike

AU - Pountney, Oliver

AU - Lock, Gary

PY - 2010

Y1 - 2010

N2 - Rotationally-induced (RI) ingress is caused by the negative pressure (relative to the external air) inside the wheelspace of a gas turbine; this negative pressure, which is created by the rotating flow in the wheel-space, drives the ingestion of hot gas through the rim seals. Externally-induced (EI) ingress is caused by the circumferential distribution of pressure created by the blades and vanes in the turbine annulus: ingress occurs in those regions where the external pressure is higher than that in the wheel-space, and egress occurs where it is lower. Although EI ingress is the dominant mechanism for hotgas ingestion in engines, there are some conditions in which RI ingress has an influence: this is referred to as combined ingress (CI). In Part 1 of this two-part paper, values of the sealing effectiveness (obtained using the incompressible orifice equations developed for EI ingress in an earlier paper) are compared with published experimental data and with results obtained using 3D steady compressible CFD (Computational Fluid Dynamics). Acceptable limits of the incompressible-flow assumption are quantified for the orifice model; for the CFD, even though the Mach number in the annulus reaches approximately 0.65, it is shown that the incompressible orifice equations are still valid. The results confirm that EI ingress is caused predominantly by the magnitude of the peak-to-trough circumferential difference of pressure in the annulus; the shape of the pressure distribution is of secondary importance for the prediction of ingress. A simple equation, derived from the orifice model, provides a very good correlation of the computed values of effectiveness. Using this correlation, it is possible to estimate the minimum sealing flow rate to prevent ingress without the need to know anything about the pressure distribution in the annulus; this makes the orifice model a powerful tool for rim-seal design.

AB - Rotationally-induced (RI) ingress is caused by the negative pressure (relative to the external air) inside the wheelspace of a gas turbine; this negative pressure, which is created by the rotating flow in the wheel-space, drives the ingestion of hot gas through the rim seals. Externally-induced (EI) ingress is caused by the circumferential distribution of pressure created by the blades and vanes in the turbine annulus: ingress occurs in those regions where the external pressure is higher than that in the wheel-space, and egress occurs where it is lower. Although EI ingress is the dominant mechanism for hotgas ingestion in engines, there are some conditions in which RI ingress has an influence: this is referred to as combined ingress (CI). In Part 1 of this two-part paper, values of the sealing effectiveness (obtained using the incompressible orifice equations developed for EI ingress in an earlier paper) are compared with published experimental data and with results obtained using 3D steady compressible CFD (Computational Fluid Dynamics). Acceptable limits of the incompressible-flow assumption are quantified for the orifice model; for the CFD, even though the Mach number in the annulus reaches approximately 0.65, it is shown that the incompressible orifice equations are still valid. The results confirm that EI ingress is caused predominantly by the magnitude of the peak-to-trough circumferential difference of pressure in the annulus; the shape of the pressure distribution is of secondary importance for the prediction of ingress. A simple equation, derived from the orifice model, provides a very good correlation of the computed values of effectiveness. Using this correlation, it is possible to estimate the minimum sealing flow rate to prevent ingress without the need to know anything about the pressure distribution in the annulus; this makes the orifice model a powerful tool for rim-seal design.

M3 - Conference contribution

VL - 4

T3 - Proceedings of the ASME Turbo Expo

SP - 1217

EP - 1234

BT - ASME Turbo Expo 2010: Power for Land, Sea, and Air, GT 2010

PB - American Society of Mechanical Engineers (ASME)

ER -