Passage-spectral method for turbomachinery long wave-length flow instabilities

Romera Hijano, David and Corral Garcia, Roque (2018). Passage-spectral method for turbomachinery long wave-length flow instabilities. In: "15th International Symposium on Unsteady Aerodynamics, Aeroacoustics & Aeroelasticity of Turbomachines ISUAAAT15", 24-27 Sep., Oxford.

Description

Title: Passage-spectral method for turbomachinery long wave-length flow instabilities
Author/s:
  • Romera Hijano, David
  • Corral Garcia, Roque
Item Type: Presentation at Congress or Conference (Article)
Event Title: 15th International Symposium on Unsteady Aerodynamics, Aeroacoustics & Aeroelasticity of Turbomachines ISUAAAT15
Event Dates: 24-27 Sep.
Event Location: Oxford
Title of Book: Proceedings of the 15th International Symposium on Unsteady Aerodynamics, Aeroacoustics & Aeroelasticity of Turbomachines ISUAAAT15
Date: 2018
Subjects:
Faculty: E.T.S. de Ingeniería Aeronáutica y del Espacio (UPM)
Department: Mecánica de Fluidos y Propulsión Aeroespacial
Creative Commons Licenses: Recognition - No derivative works - Non commercial

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Abstract

Numerical simulations of non-axisymmetric and unsteady flows are normally conducted using full-annulus geometries and U-RANS solvers. In general, nonlinear flow disturbances in time and/or space can be identified and represented by a discrete Fourier series as long as they are periodic. Single passage methods cannot capture this unsteady circumferential non-uniformities when the frequency is unknown. The identification and characterization of mechanisms related to flow instabilities with a reduction in computational resources should improve prediction methods and lead to more efficient control strategies, preserving the accuracy of a full domain solution. The proposed method presents for the first time an efficient means of approximating flows with spatial Fourier methods, extending the modeling to 3-D non-axisymmetrical unsteady flows without any assumed frequency in order to capture the long length-scale unsteady flow features of interest with a drastic reduction in number of reduced-passages to be required. Flow variables at the periodic boundaries are then continuously updated from the spatial Fourier coefficients of the uniformly spaced reduced-passage domains with the corresponding phase shift correction. An unsteady stall flow of a fan-stage at 50% (subsonic) of the design speed will be presented as a validation case to demonstrate effectiveness of the present method giving a comparison between the solution obtained with low number of harmonics against full-annulus solution. The stall unsteadiness is deterministic by higher frequency fluctuations caused by perturbations with a length-scale of the order of a blade pitch and long-wave rotating structures with length-scale of the order of the circumference domain. The present method accurately reproduces the unsteadiness associated to the large scales present in modal stall in a fan-stage with even one harmonic, capturing the characteristic features of a complex flow due to the tip leakage vortex with a propagation speed of approximately 70% to 80% of rotor speed counter to the rotation.

Funding Projects

TypeCodeAcronymLeaderTitle
Government of SpainDPI2017-84700-RUnspecifiedUnspecifiedFenómenos aeromecánicos en motores de aviación
Universidad Politécnica de MadridP1614120148UnspecifiedUnspecifiedUnspecified
Horizon 2020690714TurboNoiseBBDEUTSCHES ZENTRUM FUER LUFT - UND RAUMFAHRT EVValidation of improved turbomachinery noise prediction models and development of novel design methods for fan stages with reduced broadband noise

More information

Item ID: 57888
DC Identifier: http://oa.upm.es/57888/
OAI Identifier: oai:oa.upm.es:57888
Official URL: http://www.isuaaat.org/call-for-papers.html
Deposited by: Memoria Investigacion
Deposited on: 03 Feb 2021 11:23
Last Modified: 03 Feb 2021 11:23
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