Rotor Wake Variability in a Multistage Compressor

Key, Nicole L.; Lawless, Patrick B.; Fleeter, Sanford

doi:10.2514/6.2007-19

Cited by 4 publications

(8 citation statements)

References 9 publications

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“…1. interactions (Wn = [2,6,12,24]). This set of wavelets yields a condition number of 3.15 using the full dataset from the experiment.…”

Section: Reconstruction Of Stator 2 Downstream Total Pressure Profile Using the Full And Reduced Datasetsmentioning

confidence: 99%

“…While a smaller number of wavelets would require fewer data points to reconstruct the flow, the reduced wavelet set should still be able to characterize the flow features of interest. After comparing the magnitudes of all the wavelets in the reconstructed total pressure profile, the first 12 dominant wavelets were selected: Wn = [6,12,38,50,44,88,132,176,220,264,308,352]. The reduced wavelet set includes all eight wavelets associated with S2/IGV wakes but eliminates the higher harmonics associated with S1, S3, and the stator-stator interactions.…”

Section: V02at32a052-8mentioning

confidence: 99%

“…With multiple stages and realistic flow conditions, the facility offers the opportunity to analyze the impact of blade row interactions for computational tool validation. Though studies of the rotor wake variability have been thoroughly carried out by Key et al [6] and Smith et al [7], there are limited findings on passage-to-passage flow variations for the vane rows. In this experiment, three circumferential segments of the annulus were experimentally characterized by indexing the stators, with respect to one another, past a fixed total pressure rake.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Reconstructing Compressor Non-Uniform Circumferential Flow Field From Spatially Undersampled Data: Part 2 — Practical Application for Experiments

Lou

Matthews

Kormanik

et al. 2020

Volume 2A: Turbomachinery

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In the previous part of the paper, a novel method to reconstruct the compressor non-uniform circumferential flow field using spatially under-sampled data points is developed. In this part of the paper, the method is applied to two compressor research articles to further demonstrate the potential of the novel method in resolving the important flow features associated with these circumferential non-uniformities. In the first experiment, the static pressure field at the leading edge of a vaned diffuser in a high-speed centrifugal compressor is reconstructed using pressure readings from nine static pressure taps placed on the hub of the diffuser. The magnitude and phase information for the first three dominant wavelets are characterized. Additionally, the method shows significant advantages over the traditional averaging methods for calculating repeatable mean values of the static pressure. While using the multi-wavelet approximation method, the errors in the mean static pressure with one dropout measurement are 70% less than the pitchwise-averaging method. In the second experiment, the full-annulus total pressure field downstream of Stator 2 in a three-stage axial compressor is reconstructed from a small segment of data representing 20% coverage of the annulus. Results show very good agreement between the reconstructed total pressure profile and the experiment at a variety of spanwise locations from near hub to near shroud. The features associated with blade-row interactions accounting for passage-to-passage variations are resolved in the reconstructed total pressure profile.

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“…1. interactions (Wn = [2,6,12,24]). This set of wavelets yields a condition number of 3.15 using the full dataset from the experiment.…”

Section: Reconstruction Of Stator 2 Downstream Total Pressure Profile Using the Full And Reduced Datasetsmentioning

confidence: 99%

Section: V02at32a052-8mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Reconstructing Compressor Non-Uniform Circumferential Flow Field From Spatially Undersampled Data: Part 2 — Practical Application for Experiments

Lou

Matthews

Kormanik

et al. 2020

Volume 2A: Turbomachinery

View full text Add to dashboard Cite

show abstract

“…Key et al studied rotor wake variability caused by blade row interactions through measuring timevaried flow angle in the mid-span of each rotor exit. 11,12 Wake depth and width were selected to quantify its variability for all the stages in Purdue three-stage compressor at design and high loading operating conditions. Two distinct averaging techniques were employed to measure the contributions associated to the rotor and those related to the potential disturbances of the downstream stator.…”

Section: Introductionmentioning

confidence: 99%

“…13 The focus of the current paper is to gain depth and insight into the inner flow mechanism in the rear stages of advanced high-pressure compressors (HPC), specifically to clarify the wake variability driven by the rotor/stator and stator/stator interactions and the transfer characteristics of the frequency magnitudes of first three order harmonics in the multistage environment. Key's investigations 12 pay full attention to the mid-span, due to that the endwall performance determines the stall limits and overall performance of the high-performance compressor, our study expands it to the whole span from hub to casing locations, therefore the wake variability characteristics near the endwalls are achieved for the first time. Two rotor wake averaging techniques are employed to distinguish the effects of upstream phase-locked rotor variation and downstream vane potential effects.…”

Section: Introductionmentioning

confidence: 99%

An experimental study of rotor-stator wake unsteadiness in a multistage axial compressor

Zhang

2020

Proceedings of the Institution of Mechanical Engineers, Part G:

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The flow in a multistage axial compressor is highly unsteady, three-dimensional and turbulent. The interaction between compressor blade rows results in rotor/stator wake unsteadiness, which is not typically considered in the computational fluid dynamics (CFD) models. To gain depth and insight into the inner flow mechanism in multistage compressors, specifically the wake variability driven by the rotor/stator and stator/stator interactions, a compound total-pressure pneumatic probe with both high and low response-frequency were designed and manufactured. Unsteady rotor and stator wake measurements between blade rows for the third stage were carried out with this probe installing on a 3-DOF displacement mechanism, to deepen the knowledge of unsteady interactions in the embedded stages of a four-stage low-speed axial compressor. By performing frequency spectrum analysis and ensemble-average methods, higher spectral magnitude of the blade passing frequency (fBPF) and higher root mean square values of total pressure (PtRMS) at both sides of the stator wake region caused by the shedding of upstream boundary layer are revealed. In addition, the high-order harmonics are strengthened by the stator/stator interactions, especially near the blade tip. The individual contributions of rotor geometry variations/interactions of the upstream rotor wakes and the effects of downstream stator potential modulation to the wake variations can be understood.

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