In this paper the three-dimensional unsteady aerodynamics of a low aspect ratio, high pressure turbine stage are studied. In particular, the results of fully unsteady three-dimensional numerical simulations, performed with ANSYS-CFX, are critically evaluated against experimental data. Measurements were carried out with a novel three-dimensional fast-response pressure probe in the closed-loop test rig of the Laboratorio di Fluidodinamica delle Macchine of the Politecnico di Milano. An analysis is first reported about the strategy to limit the CPU and memory requirements while performing three-dimensional simulations of blade row interaction when the rotor and stator blade numbers are prime to each other. What emerges as the best choice is to simulate the unsteady behavior of the rotor alone by applying the stator outlet flow field as a rotating inlet boundary condition (scaled on the rotor blade pitch). Thanks to the reliability of the numerical model, a detailed analysis of the physical mechanisms acting inside the rotor channel is performed. Two operating conditions at different vane incidence are considered, in a configuration where the effects of the vortex-blade interaction are highlighted. Different vane incidence angles lead to different size, position, and strength of secondary vortices coming out from the stator, thus promoting different interaction processes in the subsequent rotor channel. However some general trends can be recognized in the vortex-blade interaction: the sense of rotation and the spanwise position of the incoming vortices play a crucial role on the dynamics of the rotor vortices, determining both the time-mean and the time-resolved characteristics of the secondary field at the exit of the stage.
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November 2012
Research Papers
Unsteady Aerodynamics of a Low Aspect Ratio Turbine Stage: Modeling Issues and Flow Physics
A. Mora,
A. Mora
Laboratorio di Fluidodinamica delle Macchine, Dipartimento di Energia, Politecnico di Milano, Via Lambruschini 4, I-20158, Milano,
Italy
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P. Gaetani,
P. Gaetani
Laboratorio di Fluidodinamica delle Macchine, Dipartimento di Energia, Politecnico di Milano, Via Lambruschini 4, I-20158, Milano,
Italy
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M. Savini
M. Savini
Dipartimento di Ingegneria Industriale,
Università degli Studi di Bergamo
, Viale Marconi 5, I-24044 Dalmine, Italy
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A. Mora
Laboratorio di Fluidodinamica delle Macchine, Dipartimento di Energia, Politecnico di Milano, Via Lambruschini 4, I-20158, Milano,
Italy
P. Gaetani
Laboratorio di Fluidodinamica delle Macchine, Dipartimento di Energia, Politecnico di Milano, Via Lambruschini 4, I-20158, Milano,
Italy
M. Savini
Dipartimento di Ingegneria Industriale,
Università degli Studi di Bergamo
, Viale Marconi 5, I-24044 Dalmine, Italy
J. Turbomach. Nov 2012, 134(6): 061030 (10 pages)
Published Online: September 12, 2012
Article history
Received:
April 1, 2011
Accepted:
April 16, 2011
Online:
September 12, 2012
Published:
September 12, 2012
Citation
Persico, G., Mora, A., Gaetani, P., and Savini, M. (September 12, 2012). "Unsteady Aerodynamics of a Low Aspect Ratio Turbine Stage: Modeling Issues and Flow Physics." ASME. J. Turbomach. November 2012; 134(6): 061030. https://doi.org/10.1115/1.4004021
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