Experimental and Computational Investigation of Flow Instabilities in Turbine Rim SealsSource: Journal of Engineering for Gas Turbines and Power:;2019:;volume( 141 ):;issue: 001::page 11028Author:Horwood, Joshua T. M.
,
Hualca, Fabian P.
,
Scobie, James A.
,
Wilson, Michael
,
Sangan, Carl M.
,
Lock, Gary D.
DOI: 10.1115/1.4041115Publisher: The American Society of Mechanical Engineers (ASME)
Abstract: In high-pressure turbines, cool air is purged through rim seals at the periphery of wheel-spaces between the stator and rotor disks. The purge suppresses the ingress of hot gas from the annulus but superfluous use is inefficient. In this paper, the interaction between the ingress, purge, and mainstream flow is studied through comparisons of newly acquired experimental results alongside unsteady numerical simulations based on the DLR TRACE solver. New experimental measurements were taken from a one-and-a-half stage axial-turbine rig operating with engine-representative blade and vane geometries, and overlapping rim seals. Radial traverses using a miniature CO2 concentration probe quantified the penetration of ingress into the rim seal and the outer portion of the wheel-space. Unsteady pressure measurements from circumferentially positioned transducers on the stator disk identified distinct frequencies in the wheel-space, and the computations reveal these are associated with large-scale flow structures near the outer periphery rotating at just less than the disk speed. It is hypothesized that the physical origin of such phenomenon is driven by Kelvin–Helmholtz instabilities caused by the tangential shear between the annulus and egress flows, as also postulated by previous authors. The presence and intensity of these rotating structures are strongly dependent on the purge flow rate. While there is general qualitative agreement between experiment and computation, it is speculated that the underprediction by the computations of the measured levels of ingress is caused by deficiencies in the turbulence modeling.
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contributor author | Horwood, Joshua T. M. | |
contributor author | Hualca, Fabian P. | |
contributor author | Scobie, James A. | |
contributor author | Wilson, Michael | |
contributor author | Sangan, Carl M. | |
contributor author | Lock, Gary D. | |
date accessioned | 2019-03-17T10:31:36Z | |
date available | 2019-03-17T10:31:36Z | |
date copyright | 10/17/2018 12:00:00 AM | |
date issued | 2019 | |
identifier issn | 0742-4795 | |
identifier other | gtp_141_01_011028.pdf | |
identifier uri | http://yetl.yabesh.ir/yetl1/handle/yetl/4256172 | |
description abstract | In high-pressure turbines, cool air is purged through rim seals at the periphery of wheel-spaces between the stator and rotor disks. The purge suppresses the ingress of hot gas from the annulus but superfluous use is inefficient. In this paper, the interaction between the ingress, purge, and mainstream flow is studied through comparisons of newly acquired experimental results alongside unsteady numerical simulations based on the DLR TRACE solver. New experimental measurements were taken from a one-and-a-half stage axial-turbine rig operating with engine-representative blade and vane geometries, and overlapping rim seals. Radial traverses using a miniature CO2 concentration probe quantified the penetration of ingress into the rim seal and the outer portion of the wheel-space. Unsteady pressure measurements from circumferentially positioned transducers on the stator disk identified distinct frequencies in the wheel-space, and the computations reveal these are associated with large-scale flow structures near the outer periphery rotating at just less than the disk speed. It is hypothesized that the physical origin of such phenomenon is driven by Kelvin–Helmholtz instabilities caused by the tangential shear between the annulus and egress flows, as also postulated by previous authors. The presence and intensity of these rotating structures are strongly dependent on the purge flow rate. While there is general qualitative agreement between experiment and computation, it is speculated that the underprediction by the computations of the measured levels of ingress is caused by deficiencies in the turbulence modeling. | |
publisher | The American Society of Mechanical Engineers (ASME) | |
title | Experimental and Computational Investigation of Flow Instabilities in Turbine Rim Seals | |
type | Journal Paper | |
journal volume | 141 | |
journal issue | 1 | |
journal title | Journal of Engineering for Gas Turbines and Power | |
identifier doi | 10.1115/1.4041115 | |
journal fristpage | 11028 | |
journal lastpage | 011028-12 | |
tree | Journal of Engineering for Gas Turbines and Power:;2019:;volume( 141 ):;issue: 001 | |
contenttype | Fulltext |