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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.
Original language | English |
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Article number | 011028 |
Pages (from-to) | 1-12 |
Number of pages | 12 |
Journal | Journal of Engineering for Gas Turbines and Power: Transactions of the ASME |
Volume | 141 |
Issue number | 1 |
Early online date | 17 Oct 2018 |
DOIs | |
Publication status | Published - 1 Jan 2019 |
ASJC Scopus subject areas
- Nuclear Energy and Engineering
- Fuel Technology
- Aerospace Engineering
- Energy Engineering and Power Technology
- Mechanical Engineering
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Dive into the research topics of 'Experimental and Computational Investigation of Flow Instabilities in Turbine Rim Seals'. Together they form a unique fingerprint.Projects
- 1 Finished
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Experimental and Theoretical Modelling of Hot Gas Ingestion through Gas-Turbine Rim Seals
Lock, G. (PI), Robinson, K. (CoI), Sangan, C. (CoI) & Wilson, M. (CoI)
Engineering and Physical Sciences Research Council
12/02/13 → 10/08/16
Project: Research council
Profiles
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James Scobie
- Department of Mechanical Engineering - Reader
- IAAPS: Propulsion and Mobility
- Centre for Sustainable Energy Systems (SES)
Person: Research & Teaching, Core staff, Affiliate staff
Equipment
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Balena High Performance Computing (HPC) System
Facility/equipment: Equipment