Unsteady Aerodynamic Interactions in a Multistage Compressor

Capece, Vincent R.; Fleeter, Sanford

doi:10.1115/1.3262122

Cited by 27 publications

(8 citation statements)

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“…One of the first studies of airfoil clocking was performed by Capece (1987), who showed the potential performance benefits. Saren et al (1994Saren et al ( ,1995Saren et al ( ,1997 have used theoretical, computational and experimental techniques to show that airfoil clocking can be used to increase performance and reduce unsteady aerodynamic loads on airfoils.…”

Section: Introductionmentioning

confidence: 99%

Physics Of Airfoil Clocking In A High-Speed Axial Compressor

Dorney¹,

Sharma²,

Gundy-Burlet³

1998

International Journal of Turbo and Jet Engines

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Axial compressors have inherently unsteady flow fields because of relative motion between rotor and stator airfoils. This relative motion leads to viscous and in viscid (potential) interactions between blade rows. As the number of stages increases in a turbomachine, the buildup of converted wakes can lead to progressively more complex wake/wake and wake/airfoil interactions. Variations in the relative circumferential positions of stators or rotors can change these interactions, leading to different unsteady forcing functions on airfoils and different compressor efficiencies. In addition, as the Mach number increases the interaction between blade rows can be intensified due to potential effects. In the current study an unsteady, quasi-three-dimensional Navier-Stokes analysis has been used to investigate the unsteady aerodynamics of stator clocking in a 1-1/2 stage compressor, typical of back stages used in high-pressure compressors of advanced commercial jet engines. The effects of turbulence have been modeled with both algebraic and two-equation models. The results presented include steady and unsteady surface pressures, efficiencies, boundary layer quantities and turbulence quantities.The main contribution of the current work has been to show that airfoil clocking can produce significant performance variations at the Mach numbers associated with an engine operating environment In addition, the growth of turbulence has been quantified to aid in the development of models for the multi-stage steady analyses used in design systems. The effects of airfoil clocking (or indexing) on turbine performance have been investigated byHuber et al. (1995), Griffin et cd. (1995) and Dorney and Sharma (1996). The studies showed changes in efficiency on the order of 0.5\% as the stators were

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Section: Introductionmentioning

confidence: 99%

Physics Of Airfoil Clocking In A High-Speed Axial Compressor

Dorney¹,

Sharma²,

Gundy-Burlet³

1998

International Journal of Turbo and Jet Engines

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“…The blade mounted transducers are statically calibrated to determine sensitivity and to insure linearity. A dynamic calibration (Capece and Fleeter, 1987) showed negligible phase shift and attenuation to 2100 Hz, three times the impeller blade pass frequency. The unsteady static pressure at the impeller exit/diffuser entrance is measured using PCB Piezotronics 103A piezoelectric transducers.…”

Section: Unste Dy Pressure Instrumentationmentioning

confidence: 95%

An Investigation of Unsteady Impeller-Diffuser Interactions in a Centrifugal Compressor

Bryan¹,

Fleeter²

1992

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“…One of the first studies of airfoil clocking was performed by Capece (1987), who showed the potential performance benefits. Saren et al (1994Saren et al ( ,1995Saren et al ( ,1997Saren et al ( ,1998 et al (1998) and Cizmas et al (1997Cizmas et al ( , 1998 Baldwin and Lomax (1978) was used in this study.…”

Section: Introductionmentioning

confidence: 99%

Full-Annulus Simulations of Airfoil Clocking in a 1-1/2 Stage Axial Compressor

Dorney¹,

Sondak²,

Cizmas³

et al. 1999

International Journal of Turbo and Jet Engines

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Axial compressors have inherently unsteady flow fields because of relative motion between rotor and stator airfoils. This relative motion leads to viscous and inviscid (potential) interactions between blade rows. As the number of stages increases in a turbomachine, the buildup of convected wakes can lead to progressively more complex wake/wake and wake/airfoil interactions. Variations in the relative circumferential positions of stators or rotors can change these interactions, leading to different unsteady forcing functions on airfoils and different compressor efficiencies. In addition, as the Mach number increases the interaction between blade rows can be intensified due to potential effects.It has been shown, both experimentally and computationally, that airfoil clocking can be used to improve the efficiency and reduce the unsteadiness in multiple-stage axial turbomachines with equal blade counts in alternate blade rows. While previous investigations have provided an improved understanding of the physics associated with airfoil clocking, more research is needed to determine if airfoil clocking is viable for use in modern gas-turbine compressors. This paper presents the results of a combined experimental/computational research effort to study the physics of airfoil clocking in a high-speed axial compressor. Computational simulations have been performed for eight different clocking positions of the stator airfoils in a 1-1/2 stage high-speed compressor. To accurately model the experimental compressor, full-annulus simulations were conducted using 34 IGV, 35 rotor and 34 stator airfoils. It is common practice to modify blade counts to reduce the computational work required to perform turbomachinery simulations, and this approximation has been made in all computational clocking studies performed to date. A simulation was also performed in the present study with 1 inlet guide vane, 1 rotor airfoil, and 1 stator airfoil to model blade rows with 34 airfoils each in order to examine the effects of this approximation. Time-averaged and unsteady data (including performance and boundary layer quantities) were examined. The predicted results indicate that simulating the full annulus gives better qualitative agreement with the experimental data, as well as more accurately modeling the interaction between adjacent blade rows.

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Unsteady Aerodynamic Interactions in a Multistage Compressor

Cited by 27 publications

References 0 publications

Physics Of Airfoil Clocking In A High-Speed Axial Compressor

Physics Of Airfoil Clocking In A High-Speed Axial Compressor

An Investigation of Unsteady Impeller-Diffuser Interactions in a Centrifugal Compressor

Full-Annulus Simulations of Airfoil Clocking in a 1-1/2 Stage Axial Compressor

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