Mistuned Higher-Order Mode Forced Response of an Embedded Compressor Rotor: Part I — Steady and Unsteady Aerodynamics

Li, Jing; Aye-Addo, Nyansafo; Kormanik, Nicholas J.; Matthews, Douglas R.; Key, Nicole L.; Kielb, Robert E.

doi:10.1115/gt2017-64633

Cited by 12 publications

(4 citation statements)

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“…For the IGV and S1 verification, three different levels of mesh densities (168,435, 314,811, and 483,075 for IGV; 174,135, 324,159, and 505,419 for S1) were conducted on a single-row, single-passage model based on the steady calculations with the same boundary conditions. Figure 3a shows the normalized absolute velocity profile at the IGV exit, which characterizes the wake and potential disturbances from upstream IGV [32]. Meanwhile, the normalized static pressure profile at the S1 inlet characterizes the potential disturbance from downstream S1, as depicted in Figure 3b.…”

Section: Computational Mesh and Code Verificationmentioning

confidence: 99%

“…Generally, the boundary profile is extracted at the interface between IGV and R1, just before the mixing plane (Case A-1). However, several studies have shown that the wake forcing function was underestimated compared with the results in a coupled configuration (Case B/Case C) due to the use of the mixing plane [11,14,32]. Hence, the boundary profile extracted at the IGV exit from the single-row steady-state calculation was investigated as a modified case (Case A-2), although it still has certain limitations and deficiencies.…”

Section: Decoupled and Coupled Configurationsmentioning

confidence: 99%

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Forced Response Analysis of an Embedded Compressor Rotor Induced by Stator Disturbances and Rotor–Stator Interactions

2023

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Accurate predictions of the blade response in a multi-row compressor is one of the most important tasks within the design process of compressor blades. Some recent studies have shown that the decoupled method considering only the stator disturbances cannot obtain accurate results for cases with strong rotor–stator interactions, especially for the interaction between the rotor and downstream stator, and the coupled method with multi-row configurations is necessary. Factors determine what computational domains to model need to be clarified to find a balance between accuracy requirements and computational costs. To this end, this study conducted full-annulus unsteady calculations with decoupled and coupled configurations to investigate the forced response of an embedded compressor rotor induced by upstream and downstream stator disturbances and rotor–stator interactions, respectively. The results show that the upstream IGV disturbances were dominated by the wake, and the IGV and S1 potential fields had little effect on the R1 response. Meanwhile, the IGV–R1 interactions and S1–R1 interactions were dominated by one cut-on mode, respectively. The comparisons of the blade vibration amplitude and the unsteady pressure field calculated by decoupled and coupled methods revealed the mechanism of the forced response, namely, for the R1 response induced by upstream aerodynamic disturbances, the dominant excitation source was the IGV wake, and the blade vibration amplitude can be predicted by the decoupled method. In terms of the response induced by downstream disturbances, the cut-on S1-R1-interaction mode was dominant and the use of the decoupled method without considering its influence will lead to an inaccurate prediction. This study concluded that the formation process of rotor–stator interactions was the key factor that determines whether the decoupled method or coupled method should be used, and analogized a process independent of the downstream stator disturbance. The results can provide a preliminary configuration for accurate and efficient blade response predictions and explain the reason why including downstream stator vanes is very important.

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Section: Computational Mesh and Code Verificationmentioning

confidence: 99%

Section: Decoupled and Coupled Configurationsmentioning

confidence: 99%

Forced Response Analysis of an Embedded Compressor Rotor Induced by Stator Disturbances and Rotor–Stator Interactions

2023

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“…However, in contrast to the enhanced capability achieved for mistuned forced response prediction [6,7], the influence of circumferential flow nonuniformity on aerodynamic excitation is less understood. 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].…”

Section: Introductionmentioning

confidence: 99%

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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“…Recently, nonlinear harmonic balance (HB) approaches have become increasingly important, as they are able to incorporate nonlinear aerodynamic effects, see e.g. Li et al (2017). Another recent research area is the influence of multi-row interactions on the aeroelastic coupling coefficients.…”

Section: Introductionmentioning

confidence: 99%

An improved reduced order model for bladed disks including multistage aeroelastic and structural coupling

Schwerdt

Maroldt

Scheidt

et al. 2023

J. Glob. Power Propuls. Soc.

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To assess the influence of mistuning on the vibration amplitudes of turbomachinery rotors, reduced order models (ROMs) are widely used. A variety of methods are available for single-stage configurations and mostly aeroelastic effects can be taken into account. More recent research focusses on extending these methods to include multiple stages. However, due to the significantly increased computational effort of the aeroelastic simulations when adding more stages to the models, these ROMs are rarely applied with the inclusion of multistage aeroelastic effects. It is therefore desirable to develop reduction methods which minimize the number of these simulations to reduce the computational cost and thereby enable analyses of rotors with multiple stages including aeroelastic effects. In this paper, a cyclic Craig-Bampton reduction method with an a priori interface reduction for multistage rotors is extended with an additional a posteriori interface reduction to reduce the number of aeroelastic simulations necessary for a given accuracy level of the ROM. The interface degrees of freedom between stages are reduced using a modified version of Characteristic Constraint Modes, to yield a more efficient representation of their displacements while retaining their monoharmonic nature. The method is applied to a two-stage axial compressor with full aeroelastic coupling between the stages and its reduced computational effort is demonstrated. Additionally, two sorting methods for the degrees of freedom (DOFs) of the ROM are compared.

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Mistuned Higher-Order Mode Forced Response of an Embedded Compressor Rotor: Part I — Steady and Unsteady Aerodynamics

Cited by 12 publications

References 0 publications

Forced Response Analysis of an Embedded Compressor Rotor Induced by Stator Disturbances and Rotor–Stator Interactions

Forced Response Analysis of an Embedded Compressor Rotor Induced by Stator Disturbances and Rotor–Stator Interactions

Accounting for Circumferential Flow Nonuniformity in a Multistage Axial Compressor

An improved reduced order model for bladed disks including multistage aeroelastic and structural coupling

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