On the Influence of an Acoustically Optimized Turbine Exit Casing onto the Unsteady Flow Field Downstream of a Low Pressure Turbine Rotor

Loris Simonassi, Manuel Zenz, Stefan Zerobin, Thorsten Selic, Franz Heitmeir, Andreas Marn

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

Abstract

Modern low pressure turbines (LPT) are designed in order to fulfil a various number of requirements such as high endurance, low noise, high efficiency, low weight and low fuel consumption. Regarding the reduction of the emitted noise,
different designs of low pressure turbine exit guide vanes (aerodynamically and/or acoustically optimized) of the turbine exit casing (TEC) were tested and their noise reduction capabilities and aerodynamic performance were evaluated. In particular, measurements of TEC-losses were performed and differences in the losses were reported.
Measurements were carried out in a one and a half stage subsonic turbine test facility at the engine relevant operating point approach. This work focuses on the study of the unsteady flow field downstream of an unshrouded low pressure turbine rotor. The influence on the upstream flow field of a TEC design including acoustically optimized vanes (Inverse cut-off TEC) is investigated and compared with a second TEC configuration without vanes (Vaneless TEC), by means of fast response aerodynamic pressure probe measurements. The second configuration served as a reference concerning the influence of TEGVs onto the upstream located LPT rotor. The interactions between the stator and rotor wakes, secondary flows and the turbine exit guide vanes potential effect are identified via modal decomposition according to the theory of Tyler and Sofrin. The main structures constituting the unsteady flow field are detected and the role of the major interaction effects in the loss generation mechanism and in the acoustic emission is analysed.
This study based on the modal analysis of the unsteady flow field offers new insight into the main interaction mechanisms and their importance in the assessment of the aerodynamic and aeroelastic performance of modern low pressure turbine exit casings.
Original languageEnglish
Title of host publicationASME Turbo Expo 2018
Subtitle of host publicationTurbomachinery Technical Conference and Exposition
PublisherAmerican Society of Mechanical Engineers (ASME)
Number of pages12
Volume2A: Turbomachinery
ISBN (Print)978-0-7918-5099-2
DOIs
Publication statusPublished - Jun 2018
EventASME Turbo Expo 2018 - Oslo, Norway
Duration: 11 Jun 201815 Jun 2018

Conference

ConferenceASME Turbo Expo 2018
CountryNorway
CityOslo
Period11/06/1815/06/18

Fingerprint

Unsteady flow
Flow fields
Turbines
Rotors
Aerodynamics
Secondary flow
Modal analysis
Acoustic emissions
Test facilities
Noise abatement
Fuel consumption
Stators
Durability

Fields of Expertise

  • Mobility & Production

Cite this

Simonassi, L., Zenz, M., Zerobin, S., Selic, T., Heitmeir, F., & Marn, A. (2018). On the Influence of an Acoustically Optimized Turbine Exit Casing onto the Unsteady Flow Field Downstream of a Low Pressure Turbine Rotor. In ASME Turbo Expo 2018: Turbomachinery Technical Conference and Exposition (Vol. 2A: Turbomachinery). [Paper No. GT2018-76725] American Society of Mechanical Engineers (ASME). https://doi.org/10.1115/GT2018-76725

On the Influence of an Acoustically Optimized Turbine Exit Casing onto the Unsteady Flow Field Downstream of a Low Pressure Turbine Rotor. / Simonassi, Loris; Zenz, Manuel; Zerobin, Stefan; Selic, Thorsten; Heitmeir, Franz; Marn, Andreas.

ASME Turbo Expo 2018: Turbomachinery Technical Conference and Exposition. Vol. 2A: Turbomachinery American Society of Mechanical Engineers (ASME), 2018. Paper No. GT2018-76725.

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

Simonassi, L, Zenz, M, Zerobin, S, Selic, T, Heitmeir, F & Marn, A 2018, On the Influence of an Acoustically Optimized Turbine Exit Casing onto the Unsteady Flow Field Downstream of a Low Pressure Turbine Rotor. in ASME Turbo Expo 2018: Turbomachinery Technical Conference and Exposition. vol. 2A: Turbomachinery, Paper No. GT2018-76725, American Society of Mechanical Engineers (ASME), ASME Turbo Expo 2018 , Oslo, Norway, 11/06/18. https://doi.org/10.1115/GT2018-76725
Simonassi L, Zenz M, Zerobin S, Selic T, Heitmeir F, Marn A. On the Influence of an Acoustically Optimized Turbine Exit Casing onto the Unsteady Flow Field Downstream of a Low Pressure Turbine Rotor. In ASME Turbo Expo 2018: Turbomachinery Technical Conference and Exposition. Vol. 2A: Turbomachinery. American Society of Mechanical Engineers (ASME). 2018. Paper No. GT2018-76725 https://doi.org/10.1115/GT2018-76725
Simonassi, Loris ; Zenz, Manuel ; Zerobin, Stefan ; Selic, Thorsten ; Heitmeir, Franz ; Marn, Andreas. / On the Influence of an Acoustically Optimized Turbine Exit Casing onto the Unsteady Flow Field Downstream of a Low Pressure Turbine Rotor. ASME Turbo Expo 2018: Turbomachinery Technical Conference and Exposition. Vol. 2A: Turbomachinery American Society of Mechanical Engineers (ASME), 2018.
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abstract = "Modern low pressure turbines (LPT) are designed in order to fulfil a various number of requirements such as high endurance, low noise, high efficiency, low weight and low fuel consumption. Regarding the reduction of the emitted noise,different designs of low pressure turbine exit guide vanes (aerodynamically and/or acoustically optimized) of the turbine exit casing (TEC) were tested and their noise reduction capabilities and aerodynamic performance were evaluated. In particular, measurements of TEC-losses were performed and differences in the losses were reported. Measurements were carried out in a one and a half stage subsonic turbine test facility at the engine relevant operating point approach. This work focuses on the study of the unsteady flow field downstream of an unshrouded low pressure turbine rotor. The influence on the upstream flow field of a TEC design including acoustically optimized vanes (Inverse cut-off TEC) is investigated and compared with a second TEC configuration without vanes (Vaneless TEC), by means of fast response aerodynamic pressure probe measurements. The second configuration served as a reference concerning the influence of TEGVs onto the upstream located LPT rotor. The interactions between the stator and rotor wakes, secondary flows and the turbine exit guide vanes potential effect are identified via modal decomposition according to the theory of Tyler and Sofrin. The main structures constituting the unsteady flow field are detected and the role of the major interaction effects in the loss generation mechanism and in the acoustic emission is analysed.This study based on the modal analysis of the unsteady flow field offers new insight into the main interaction mechanisms and their importance in the assessment of the aerodynamic and aeroelastic performance of modern low pressure turbine exit casings.",
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N2 - Modern low pressure turbines (LPT) are designed in order to fulfil a various number of requirements such as high endurance, low noise, high efficiency, low weight and low fuel consumption. Regarding the reduction of the emitted noise,different designs of low pressure turbine exit guide vanes (aerodynamically and/or acoustically optimized) of the turbine exit casing (TEC) were tested and their noise reduction capabilities and aerodynamic performance were evaluated. In particular, measurements of TEC-losses were performed and differences in the losses were reported. Measurements were carried out in a one and a half stage subsonic turbine test facility at the engine relevant operating point approach. This work focuses on the study of the unsteady flow field downstream of an unshrouded low pressure turbine rotor. The influence on the upstream flow field of a TEC design including acoustically optimized vanes (Inverse cut-off TEC) is investigated and compared with a second TEC configuration without vanes (Vaneless TEC), by means of fast response aerodynamic pressure probe measurements. The second configuration served as a reference concerning the influence of TEGVs onto the upstream located LPT rotor. The interactions between the stator and rotor wakes, secondary flows and the turbine exit guide vanes potential effect are identified via modal decomposition according to the theory of Tyler and Sofrin. The main structures constituting the unsteady flow field are detected and the role of the major interaction effects in the loss generation mechanism and in the acoustic emission is analysed.This study based on the modal analysis of the unsteady flow field offers new insight into the main interaction mechanisms and their importance in the assessment of the aerodynamic and aeroelastic performance of modern low pressure turbine exit casings.

AB - Modern low pressure turbines (LPT) are designed in order to fulfil a various number of requirements such as high endurance, low noise, high efficiency, low weight and low fuel consumption. Regarding the reduction of the emitted noise,different designs of low pressure turbine exit guide vanes (aerodynamically and/or acoustically optimized) of the turbine exit casing (TEC) were tested and their noise reduction capabilities and aerodynamic performance were evaluated. In particular, measurements of TEC-losses were performed and differences in the losses were reported. Measurements were carried out in a one and a half stage subsonic turbine test facility at the engine relevant operating point approach. This work focuses on the study of the unsteady flow field downstream of an unshrouded low pressure turbine rotor. The influence on the upstream flow field of a TEC design including acoustically optimized vanes (Inverse cut-off TEC) is investigated and compared with a second TEC configuration without vanes (Vaneless TEC), by means of fast response aerodynamic pressure probe measurements. The second configuration served as a reference concerning the influence of TEGVs onto the upstream located LPT rotor. The interactions between the stator and rotor wakes, secondary flows and the turbine exit guide vanes potential effect are identified via modal decomposition according to the theory of Tyler and Sofrin. The main structures constituting the unsteady flow field are detected and the role of the major interaction effects in the loss generation mechanism and in the acoustic emission is analysed.This study based on the modal analysis of the unsteady flow field offers new insight into the main interaction mechanisms and their importance in the assessment of the aerodynamic and aeroelastic performance of modern low pressure turbine exit casings.

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