Flow Field Unsteadiness in the Tip Region of a Transonic Compressor Rotor

Puterbaugh, Steven L.; Copenhaver, William W.

doi:10.1115/1.2819097

Cited by 7 publications

(5 citation statements)

References 27 publications

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“…The linear model of steam force can only be used in a very narrow operational range, and is far from explaining most of the reported accidents caused by steam force. Equation (10) shows that the steam force is no longer simply linear to the displacement and velocity of the rotor as in the literature. Only when the displacement and velocity of the rotor are very small does equation ( 10) degenerate into linearity, as the square items become much smaller than the linear ones.…”

Section: Application To a Rotating Blade Row With Tip Clearancementioning

confidence: 87%

“…Computational approaches include efforts due to Dawes [4], Moore and Ransmayr [5], Liu and Bozzola [6], and many other scientists. Experimental achievements are reported by Kang and Hirsch ‰7; 8Š, Stauter [9], Puterbaugh and Copenhaver [10], and so on. Each of these studies indicate that the tip leakage in uences the three-dimensional ow performance in the overall ow path, in particular near the tip region.…”

Section: Introductionmentioning

confidence: 99%

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Models of steam force and torque of a rotor subjected to the leakage of tip clearance

Huang

2002

Proceedings of the Institution of Mechanical Engineers, Part A:

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The topic of this paper is focused on the models of steam force and torque of a rotor subjected to the leakage of tip clearance. The unsteady three-dimensional Navier-Stokes solver is used to simulate the ow eld for a rotating blade row with a tip clearance. The basic algorithm time marches the fully threedimensional unsteady equations of motion expressed in a nite volume form. The Baldwin-Lomax model is used as turbulence model. By simulating the complex ow eld including oscillating tip clearance with rotor vibration, the instantaneous asymmetry and oscillatory pressures acting on the surfaces of the blade row can be acquired, and the instantaneous steam force and torque acting on the rotor can be calculated. A new nonlinear model of steam force is created in this paper, and a model of steam torque excited by leakage is also reported.

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Section: Application To a Rotating Blade Row With Tip Clearancementioning

confidence: 87%

Section: Introductionmentioning

confidence: 99%

Models of steam force and torque of a rotor subjected to the leakage of tip clearance

Huang

2002

Proceedings of the Institution of Mechanical Engineers, Part A:

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“…The tip leakage flow and the shock structure are highly interactive with each other. When compressor operates towards the stall limit, the tip leakage vortex breakdown occurs after the shock front, which leads to compressor stall [23][24][25]. Thus, the corner between the casing wall and the blade suction surfaces is the dominant region on determining the compressor performance [26], and special care is needed in simulations.…”

Section: Extraction Of Compressor Flow Featuresmentioning

confidence: 99%

Machine Learning Uncertainty Quantification of Spalart-Allmaras Turbulence Model for Compressors

He¹,

Zhao²,

Vahdati³

2019

Proceedings of Global Power &Amp; Propulsion Society

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Turbulence models in Reynolds-Averaged Navier-Stokes simulations have a crucial effect on the compressor stability boundary. In this paper, the parametric uncertainty of the Spalart-Allmaras turbulence model on compressor flows is quantified by a metamodel-based Monte Carlo method. The model coefficients are represented by uniform distributions within intervals, and the quantities of interest include the Reynolds stress distribution, the shock front location and pressure coefficient and the separation size. An artificial neural network from machine learning is applied as the metamodel, which is tuned, trained, and tested by databases from the flow solver to achieve an error below 1% of the database range. The uncertainty of quantities of interest is determined by the range of the metamodel and the database samples from the flow solver. The sensitivity of model coefficients is quantified by calculating the gradient of quantities of interest from the metamodel. Results show that the measured data of Reynolds stress profiles in separated regions, shock front location and pressure coefficient and shock-induced separation size cannot be well captured. Crucial model coefficients on the quantities of interest are identified by a sensitivity analysis. However, re-calibration of these coefficients is contradictory in different quantities of interest and flow regimes. It indicates the need for a modified Spalart-Allmaras turbulence model form to improve the accuracy in predicting compressor flows.

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“…All pressure measurements were phase-locked relative to the position of the blade at the top-dead-center. The ensemble average of the pressure was then taken from the phase-locked data [4][5].…”

Section: Signal Analysis Techniquesmentioning

confidence: 99%

Unsteady Aerodynamic Interaction in a Closely Coupled Turbine Consistent With Contrarotation

Ooten

Anthony

Lethander

et al. 2016

Journal of Turbomachinery

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The focus of the study presented here was to investigate the interaction between the blade and downstream vane of a stage-and-one-half transonic turbine via computation fluid dynamic (CFD) analysis and experimental data. A Reynolds-averaged Navier–Stokes (RANS) flow solver with the two-equation Wilcox 1998 k–ω turbulence model was used as the numerical analysis tool for comparison with all of the experiments conducted. The rigor and fidelity of both the experimental tests and numerical analysis methods were built through two- and three-dimensional steady-state comparisons, leading to three-dimensional time-accurate comparisons. This was accomplished by first testing the midspan and quarter-tip two-dimensional geometries of the blade in a linear transonic cascade. The effects of varying the incidence angle and pressure ratio on the pressure distribution were captured both numerically and experimentally. This was used during the stage-and-one-half post-test analysis to confirm that the target corrected speed and pressure ratio were achieved. Then, in a full annulus facility, the first vane itself was tested in order to characterize the flowfield exiting the vane that would be provided to the blade row during the rotating experiments. Finally, the full stage-and-one-half transonic turbine was tested in the full annulus cascade with a data resolution not seen in any studies to date. A rigorous convergence study was conducted in order to sufficiently model the flow physics of the transonic turbine. The surface pressure traces and the discrete Fourier transforms (DFT) thereof were compared to the numerical analysis. Shock trajectories were tracked through the use of two-point space–time correlation coefficients. Very good agreement was seen when comparing the numerical analysis to the experimental data. The unsteady interaction between the blade and downstream vane was well captured in the numerical analysis.

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Flow Field Unsteadiness in the Tip Region of a Transonic Compressor Rotor

Cited by 7 publications

References 27 publications

Models of steam force and torque of a rotor subjected to the leakage of tip clearance

Models of steam force and torque of a rotor subjected to the leakage of tip clearance

Machine Learning Uncertainty Quantification of Spalart-Allmaras Turbulence Model for Compressors

Unsteady Aerodynamic Interaction in a Closely Coupled Turbine Consistent With Contrarotation

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