Modelling Turbine Acoustic Impedance
We quantify the sensitivity of turbine acoustic impedance to aerodynamic design parameters. Impedance boundary conditions are an influential yet uncertain parameter in predicting the thermoacoustic stability of gas turbine combustors. We extend the semi-actuator disk model to cambered blades, using...
| Main Authors: | , |
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| Format: | Article |
| Language: | English |
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MDPI AG
2021-06-01
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| Series: | International Journal of Turbomachinery, Propulsion and Power |
| Subjects: | |
| Online Access: | https://www.mdpi.com/2504-186X/6/2/18 |
| _version_ | 1797531194270679040 |
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| author | James Brind Graham Pullan |
| author_facet | James Brind Graham Pullan |
| author_sort | James Brind |
| collection | DOAJ |
| description | We quantify the sensitivity of turbine acoustic impedance to aerodynamic design parameters. Impedance boundary conditions are an influential yet uncertain parameter in predicting the thermoacoustic stability of gas turbine combustors. We extend the semi-actuator disk model to cambered blades, using non-linear time-domain computations of turbine vane and stage cascades with acoustic forcing for validation data. Discretising cambered aerofoils into multiple disks improves reflection coefficient predictions, reducing error by up to an order of magnitude compared to a flat plate assumption. A parametric study of turbine stage designs using the analytical model shows acoustic impedance is a weak function of degree of reaction and polytropic efficiency. The design parameter with the strongest influence is flow coefficient, followed by axial velocity ratio and Mach number. We provide the combustion engineer with improved tools to predict impedance boundary conditions, and suggest thermoacoustic stability is most likely to be compromised by change in turbine flow coefficient. |
| first_indexed | 2024-03-10T10:40:26Z |
| format | Article |
| id | doaj.art-da3eeb87789e4e358231fe487409f5b1 |
| institution | Directory Open Access Journal |
| issn | 2504-186X |
| language | English |
| last_indexed | 2024-03-10T10:40:26Z |
| publishDate | 2021-06-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | International Journal of Turbomachinery, Propulsion and Power |
| spelling | doaj.art-da3eeb87789e4e358231fe487409f5b12023-11-21T23:02:16ZengMDPI AGInternational Journal of Turbomachinery, Propulsion and Power2504-186X2021-06-01621810.3390/ijtpp6020018Modelling Turbine Acoustic ImpedanceJames Brind0Graham Pullan1Whittle Laboratory, University of Cambridge, 1 JJ Thomson Avenue, Cambridge CB3 0DY, UKWhittle Laboratory, University of Cambridge, 1 JJ Thomson Avenue, Cambridge CB3 0DY, UKWe quantify the sensitivity of turbine acoustic impedance to aerodynamic design parameters. Impedance boundary conditions are an influential yet uncertain parameter in predicting the thermoacoustic stability of gas turbine combustors. We extend the semi-actuator disk model to cambered blades, using non-linear time-domain computations of turbine vane and stage cascades with acoustic forcing for validation data. Discretising cambered aerofoils into multiple disks improves reflection coefficient predictions, reducing error by up to an order of magnitude compared to a flat plate assumption. A parametric study of turbine stage designs using the analytical model shows acoustic impedance is a weak function of degree of reaction and polytropic efficiency. The design parameter with the strongest influence is flow coefficient, followed by axial velocity ratio and Mach number. We provide the combustion engineer with improved tools to predict impedance boundary conditions, and suggest thermoacoustic stability is most likely to be compromised by change in turbine flow coefficient.https://www.mdpi.com/2504-186X/6/2/18turbineacoustic impedanceaeroacousticsthermoacoustic stability |
| spellingShingle | James Brind Graham Pullan Modelling Turbine Acoustic Impedance International Journal of Turbomachinery, Propulsion and Power turbine acoustic impedance aeroacoustics thermoacoustic stability |
| title | Modelling Turbine Acoustic Impedance |
| title_full | Modelling Turbine Acoustic Impedance |
| title_fullStr | Modelling Turbine Acoustic Impedance |
| title_full_unstemmed | Modelling Turbine Acoustic Impedance |
| title_short | Modelling Turbine Acoustic Impedance |
| title_sort | modelling turbine acoustic impedance |
| topic | turbine acoustic impedance aeroacoustics thermoacoustic stability |
| url | https://www.mdpi.com/2504-186X/6/2/18 |
| work_keys_str_mv | AT jamesbrind modellingturbineacousticimpedance AT grahampullan modellingturbineacousticimpedance |