Statistical and theoretical models of ingestion through turbine rim seals

Kunyuan Zhou, Simon N. Wood, J. Michael Owen

Research output: Contribution to journalArticle

30 Citations (Scopus)

Abstract

In recent papers, orifice models have been developed to calculate the amount of ingestion, or ingress, that occurs through gas-turbine rim seals. These theoretical models can be used for externally-induced (EI) ingress, where the pressure differences in the main gas path are dominant, and for rotationally-induced (RI) ingress, where the effects of rotation in the wheel-space are dominant. Explicit 'effectiveness equations', derived from the orifice models, are used to express the flow rate of sealing air in terms of the sealing effectiveness. These equations contain two unknown terms: Φmin, a sealing flow parameter, and Γc, the ratio of the discharge coefficients for ingress and egress. The two unknowns can be determined from concentration measurements in experimental rigs. In this paper, maximum likelihood estimation is used to fit the effectiveness equations to experimental data and to determine the optimum values of Φmin and Γc. The statistical model is validated numerically using noisy data generated from the effectiveness equations, and the simulated tests show the dangers of drawing conclusions from sparse data points. Using the statistical model, good agreement between the theoretical curves and several sets of previously-published effectiveness data is achieved for both EI and RI ingress. The statistical and theoretical models have also been used to analyse previously-unpublished experimental data, the results of which are included in separate papers. It is the ultimate aim of this research to apply the effectiveness data obtained at rig conditions to engine-operating conditions.
Original languageEnglish
Article number021014
Number of pages8
JournalJournal of Turbomachinery: Transactions of the ASME
Volume135
Issue number2
DOIs
Publication statusPublished - 1 Nov 2012
EventASME 2011 Turbo Expo: Turbine Technical Conference and Exposition, GT2011 - Vancouver, Canada
Duration: 5 Jun 20119 Jun 2011

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