Flow instability effects related to purge through a gas turbine chute seal

Arijit Roy, Jens Fridh, James Scobie, Carl Sangan, Gary Lock

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Abstract

This paper investigates flow instabilities inside the cavity formed between the stator and rotor disks of a high-speed turbine rig. The cavity rim seal is of chute seal design. The influence of flow coefficient on the sealing effectiveness at constant purge flow rate through the wheel-space is determined. The effectiveness at different radial positions over a range of purge flow conditions and flow coefficients is also studied. Unsteady pressure measurements have identified the frequency of instabilities that form within the rim seal, phenomena which have been observed in other studies. Frequencies of these disturbances, and their correlation in the circumferential direction have determined the strength and speed of rotation of the instabilities within the cavity. Large scale unsteady rotational structures have been identified, which show similarity to previous studies. These disturbances have been found to be weakly dependent on the purge flow and flow coefficients, although an increased purge reduced both the intensity and speed of rotation of the instabilities. Additionally, certain uncorrelated disturbances have been found to be inconsistent (discontinuous) with pitchwise variation.
Original languageEnglish
Pages (from-to)111-125
Number of pages15
JournalJournal of the Global Power and Propulsion Society
Volume5
DOIs
Publication statusPublished - 24 Aug 2021

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