Aeroelastic Computations of a Compressor Stage Using the Harmonic Balance Method

Reddy, T. S. R.; Bakhle, Milind A.

doi:10.2514/6.2009-5420

Cited by 3 publications

(2 citation statements)

References 11 publications

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“…Based on the amplitudes of the aero dynamic forcing functions and the resulting displacements, the IGV-rotor case has a higher aerodynamic damping coefficient of 0.104, compared to the IR, where it is 0.065, resulting in a differ ence of 38%. These values of CA are typical of turbomachinery blades and commonly reported, however, in the context of aeroelastic instabilities such as flutter, and also investigated by others [14,[33][34][35]. However, in this case, CA highlights the effect of an additional source of aerodynamic loading and how it can counter intuitively lower the magnitude of displacement and therefore, mean stresses.…”

Section: Fsi: Structural Mechanicsmentioning

confidence: 66%

Aeromechanical Modeling of Rotating Fan Blades to Investigate High-Cycle and Low-Cycle Fatigue Interaction

Dhopade

Neely

2015

Journal of Engineering for Gas Turbines and Power

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Gas turbine engine components are subject to both low-cycle fatigue (LCF) and highcycle fatigue (HCF) loads. To improve engine reliability, durability and maintenance, it is necessary to understand the interaction of LCF and HCF in these components, which can adversely affect the overall life of the engine while they are occurring simultaneously during a flight cycle. A fully coupled aeromechanical fluid-structure interaction (FSI) analysis in conjunction with a fracture mechanics analysis was numerically performed to predict the effect of representative fluctuating loads on the fatigue life ofbliskfan blades. This was achieved by comparing an isolated rotor (IR) to a rotor in the presence of upstream inlet guide vanes (IGVs). A fracture mechanics analysis was used to combine the HCF loading spectrum with an LCF loading spectrum from a simplified engine flight cycle in order to determine the extent of the fatigue life reduction due to the interaction of the HCF and LCF loads occurring simultaneously. The results demonstrate the reduced fatigue life of the blades predicted by a combined loading of HCF and LCF cycles from a crack growth analysis, as compared to the effect of the individual cycles. In addition, the HCF aerodynamic forcing from the IGVs excited a higher natural frequency of vibration o f the rotor blade, which was shown to have a detrimental effect on the fatigue life. The findings suggest that FSI, blade-row interaction and HCF I LCF interaction are important considerations when predicting blade life at the design stage of the engine. The lack of available experimental data to validate this problem emphasizes the utility of a numerical approach to first examine the physics of the problem and second to help establish the need for these complex experiments.

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Section: Fsi: Structural Mechanicsmentioning

confidence: 66%

Aeromechanical Modeling of Rotating Fan Blades to Investigate High-Cycle and Low-Cycle Fatigue Interaction

Dhopade

Neely

2015

Journal of Engineering for Gas Turbines and Power

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“…The HB method has been extensively applied and validated for external flows [14][15][16][17], considering both aerodynamics and aeroelasticity. However, when it comes to turbomachinery aeroelasticity, validation against experimental data remains an open issue [18][19][20][21][22][23].…”

Section: Introductionmentioning

confidence: 99%

Time-Domain Harmonic Balance Method for Turbomachinery Aeroelasticity

et al. 2014

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On the Nature of Transonic Shock Buffet in an Axial-Flow Fan

Ranjan Majhi,

Venkatraman

2023

AIAA Journal

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Transonic buffet or self-sustained shock oscillation in transonic flow is not well-understood in fans and compressors. The present work is a numerical study of transonic buffet flow using a full-annulus model of a transonic fan—the NASA rotor 67. Firstly, results obtained with steady simulations are validated with experimental and numerical data available, and shock structures from these simulations are found to exhibit distinct features as seen in experiments. Unsteady Reynolds-averaged Navier–Stokes simulations are then carried out at two operating points—near design mass flow rate and toward stall—on the fan characteristic to capture transonic shock buffet. The unsteady simulations are able to capture necessary attributes of transonic buffet flow. Further, wave propagation in an unsteady flow solution featuring transonic buffet is investigated to understand the mechanism driving shock buffet in axial turbomachines. Upstream- and downstream-propagating pressure perturbation waves are observed on the blade suction surface within a buffet cycle, while only an upstream-propagating wave is seen on the blade pressure surface. The driving mechanism of transonic buffet in this turbomachine is elucidated through a feedback loop of the upstream- and downstream-propagating waves—qualitatively and quantitatively. Besides the streamwise pressure waves, circumferential pressure waves propagating at part speed of the rotor in the spinning direction and radially outward moving pressure waves of similar speeds on the blade suction and pressure surfaces are also detected as distinct features of buffet flow for this turbomachine.

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Aeroelastic Computations of a Compressor Stage Using the Harmonic Balance Method

Cited by 3 publications

References 11 publications

Aeromechanical Modeling of Rotating Fan Blades to Investigate High-Cycle and Low-Cycle Fatigue Interaction

Aeromechanical Modeling of Rotating Fan Blades to Investigate High-Cycle and Low-Cycle Fatigue Interaction

Time-Domain Harmonic Balance Method for Turbomachinery Aeroelasticity

On the Nature of Transonic Shock Buffet in an Axial-Flow Fan

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