Unsteady flow interactions between a high- and low-pressure turbine: Part 2 — Rotor-synchronic averaging and proper orthogonal decomposition of the unsteady flow fields

M. Dellacasagrande, P. Z. Sterzinger, S. Zerobin, F. Merli, L. Wiesinger, A. Peters, G. Maini, F. Heitmeir, E. Göttlich

Research output: Chapter in Book/Report/Conference proceedingConference paperpeer-review


This paper, the second of two parts, presents an experimental investigation of the unsteady flow field evolving in a two-stage two-spool test turbine facility. The experimental setup, which was designed to reproduce the operating condition of modern commercial aero-engines, consists of a high-pressure turbine (HPT) stage followed by a turbine center frame (TCF) with non-turning struts, and a co-rotating low-pressure turbine (LPT) stage. Measurements carried out with a fast-response aerodynamic pressure probe (FRAPP) were post-processed to describe the unsteady evolution of the flow downstream of the HPT rotor, through the TCF duct, and at the exit of the LPT stage. The time-resolved results presented in the first part of this paper show that deterministic fluctuations due to both rotors characterize the flow field downstream of the LPT. In order to characterize the deterministic unsteadiness induced by all the components constituting the turbine facility (HPT, TCF and LPT) and their interactions, measurements were carried out in three different planes located downstream of the HPT, at the exit of the TCF and downstream of the LPT stage. The unsteady results obtained in the plane located at the exit of the LPT are discussed in more details in this second part of this paper, providing information about the interactions between the two rotors. A proper phase-average procedure, known as rotor syn-chronic averaging (RSA), which takes into account the rotor-rotor interaction, was adopted to capture the unsteadiness due to both rotors. Proper Orthogonal Decomposition (POD) was also applied to provide a characterization of the major contributors in terms of energy to the deterministic unsteadiness occurring in the test turbine facility. At the exit of the LPT rotor, the perturbations induced by the HPT stage and the interactions between the two rotors were found to dominate over the unsteadiness due to the LPT only.

Original languageEnglish
Title of host publicationTurbomachinery
PublisherAmerican Society of Mechanical Engineers (ASME)
ISBN (Electronic)9780791858554
Publication statusPublished - 1 Jan 2019
EventASME Turbo Expo 2019: Turbomachinery Technical Conference & Exhibition - Phoenix, United States
Duration: 17 Jun 201921 Jun 2019

Publication series

NameProceedings of the ASME Turbo Expo


ConferenceASME Turbo Expo 2019
Country/TerritoryUnited States

ASJC Scopus subject areas

  • Engineering(all)

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