Effects of Circumferential Nonuniformity in Compressor Flow Fields Including Vane Wake Variability

Methel, Jeanne; Smith, Natalie R.; Berdanier, Reid A.; Key, Nicole L.

doi:10.2514/1.b36440

Cited by 2 publications

(6 citation statements)

References 17 publications

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“…The wake from the upstream blade row and the potential field from the downstream blade row are considered the main causes for excitation, and the aerodynamic excitation reduced from steady single-passage computational fluid dynamics (CFD) simulations [6,8] is typically used to predict the rotor resonant response. However, the results from Methel et al showed more than 60% variations in spectral magnitudes of the fundamental forcing frequency due to stator wake variability among investigated passages [4]. In a recent study, Schoenenborn [9] suggested that the aerodynamic excitation can change significantly from blade to blade due to the superposition of the Tyler-Sofrin (or scattered or spinning) modes, which refer to the acoustic interaction with blade rows further upstream or downstream and may have a significant impact on blade forcing.…”

Section: Introductionmentioning

confidence: 90%

“…Even when a facility has the capability to traverse a probe circumferentially, it is still a challenging task to perform a full-annulus traverse to capture the circumferential flow nonuniformity. To the authors' best knowledge, the only study in the open literature with a focus on experimental characterization of the stator wakes and their variability was conducted by Methel et al [4] in a threestage axial compressor. A minimum of 6 wakes and a maximum of 12 wakes were measured at the exit of each vane row by simultaneously indexing all vane rows along the circumferential direction.…”

Section: Scope Of the Articlementioning

confidence: 99%

“…The ambient reference pressure was measured using a high accuracy barometric transducer with ±0.073% full-scale accuracy. In combination with the measured gage pressures, the largest uncertainty on individual stage total pressure ratio is less than 2 × 10 −4 [4]. At the end of the test campaign, a total of seven traverses were performed, covering approximately 58.6 deg of effective travel around the annulus for each rake or 16.3% of the entire annulus.…”

Section: Experimental Approachmentioning

confidence: 99%

“…Research has shown that the calculated efficiency is more sensitive to variations in total temperature [14]. Therefore, the variations in stage efficiency can be significant, up to 15 points variation in the calculated stage efficiency at peak efficiency condition [4].…”

Section: Passage-passage Variation and Its Effects On Stagementioning

confidence: 99%

“…For instance, He et al [3] conducted a fullannulus unsteady Reynolds-averaged Navier-Stokes (URANS) simulation in a 3.5-stage axial compressor at midspan and showed that the circumferentially nonuniform flow can cause more than a one-point error in compressor stage performance measurements. Later, Methel et al [4] experimentally characterized the stator wake variability in a three-stage axial compressor through a rigorous traverse of different vane passages. Results showed three points in variation in overall compressor efficiency and up to 15 points variation for individual stage efficiency based on pressure and temperature variations observed among passages.…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Accounting for Circumferential Flow Nonuniformity in a Multistage Axial Compressor

Lou

Matthews²,

Kormanik³

et al. 2023

Journal of Turbomachinery

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The flow field in a compressor is circumferentially non-uniform due to geometric imperfections, inlet flow nonuniformities, and blade row interactions. Therefore, the flow field, as represented by measurements from discrete stationary instrumentation, can be skewed and contribute to uncertainties in both calculated one-dimensional performance parameters and aerodynamic forcing functions needed for aeromechanics analyses. Considering this challenge, this paper documents a continued effort to account for compressor circumferential flow nonuniformities based on discrete, under-sampled measurements. First, the total pressure field downstream of the first two stators in a three-stage axial compressor was measured across half of the annulus. The circumferential nonuniformities in the stator exit flow, including vane wake variability, were characterized. In addition, the influence of wake variation on stage performance calculations and aerodynamic forcing functions were investigated. In the present study for the compressor with an approximate pressure ratio of 1.3 at design point, the circumferential nonuniformity in total pressure yields an approximate 2.4-point variation in isentropic efficiency and 54% variation in spectral magnitudes of the fundamental forcing frequency for the embedded stage. Furthermore, the stator exit circumferential flow nonuniformity is accounted for by reconstructing the full-annulus flow using a novel multi-wavelet approximation method. The features associated with wake-wake interactions accounting for passage-to-passage variations are resolved in the reconstructed total pressure profile, yielding representative mean flow properties and aerodynamic forcing functions.

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Section: Introductionmentioning

confidence: 90%

Section: Scope Of the Articlementioning

confidence: 99%

Section: Experimental Approachmentioning

confidence: 99%

Section: Passage-passage Variation and Its Effects On Stagementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Accounting for Circumferential Flow Nonuniformity in a Multistage Axial Compressor

Lou

Matthews²,

Kormanik³

et al. 2023

Journal of Turbomachinery

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Resolving nonuniform flow in gas turbines: challenges, progress, and moving forward

Lou

2024

Aeronaut. j.

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The flow in gas turbines exhibits a highly unsteady, complex and nonuniform manner, which presents two main challenges. Firstly, it introduces instrumentation errors, contributing to uncertainties when calculating one-dimensional performance metrics during rig or engine tests using fixed-location rakes. Secondly, it raises mechanical concerns, including high-cycle fatigue due to blade row interactions in turbomachines and thermal fatigue caused by hot-streaks at the combustor exit. Experimental characterisation of the flow nonuniformity in gas turbines is highly challenging due to the confined space and harsh environment for instrumentation. This paper presents recent efforts to address this issue by resolving the nonuniform flow in gas turbines using spatially under-sampled measurements. The proposed approach utilises discrete probe data and leverages a ‘Fourier-based approximation’ method developed by the author. The technique has undergone preliminary experimental validation involving reconstruction of the total pressure distribution in a multi-stage axial compressor and the total temperature field at the exit of the combustor and high-pressure turbine. Results show that, in the multi-stage axial compressor environment, reconstruction of inter-stage total pressure is achieved using a reduced dataset covering less than 20% of the annulus with reasonably good accuracy. The reconstructed total pressure yields almost identical mean total pressure values at all spanwise locations, with a maximum deviation of less than 0.02%. Additionally, reconstruction of the total temperature distribution at an engine-representative full annulus combustor is achieved using measurements at ten carefully selected circumferential locations. Results show that the reconstructed temperature field successfully captures the primary features associated with combustor exit temperature flow. The reconstructed temperature field yields excellent agreement in the magnitude of radial temperature distribution factor (RTDF) and overall temperature distribution factor (OTDF) predictions to the experiment, with a deviation of less than 0.5% for RTDF and less than 2.5% for OTDF. Lastly, reconstruction of the total temperature distribution at the exit of the GE E3 high-pressure turbine (HPT) is achieved using measurements at eight carefully selected circumferential locations. Results demonstrate remarkable robustness in resolving the temperature profile at the HPT exit with high fidelity, irrespective of the HPT inlet conditions. The initial validation results are promising, demonstrating that the new probe layout scheme and the Fourier-based approximation method enable effective characterisation of flow nonuniformity in gas turbines, thereby providing valuable insights into the complex flow of gas turbine engines.

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Effects of Circumferential Nonuniformity in Compressor Flow Fields Including Vane Wake Variability

Cited by 2 publications

References 17 publications

Accounting for Circumferential Flow Nonuniformity in a Multistage Axial Compressor

Accounting for Circumferential Flow Nonuniformity in a Multistage Axial Compressor

Resolving nonuniform flow in gas turbines: challenges, progress, and moving forward

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