Thermoacoustic instabilities pose a major threat to modern gas turbines. The use of acoustic dampers, like Helmholtz resonators, has proven useful for the mitigation of such instabilities. However, assessing the effect of acoustic dampers on thermoacoustic modes in annular combustion chambers remains an intricate task. This results from the implicit nature of the thermoacoustic Helmholtz equation associated with the high number of possible parameter values for the positioning of the dampers and their impedance design. In the present work, the principal challenges of the effective placement and the design of the impedance of acoustic dampers in annular chambers are discussed. This includes the choice of an appropriate objective function for the optimization, the combinatorial challenges when dealing with different possible damper arrangements, and the numerical complexities when using the thermoacoustic Helmholtz equation to approach this issue. As a key aspect, the paper proposes a new adjoint-based approach to tackle these problems. The new algorithm establishes algebraic models that predict the effect of acoustic dampers on the growth rates of the thermoacoustic modes. The theory is exemplified on the basis of a generic annular combustor model with 12 burners.


    Access

    Access via TIB

    Check availability in my library

    Order at Subito €


    Export, share and cite



    Title :

    Acoustic Damper Placement and Tuning for Annular Combustors: An Adjoint-Based Optimization Study


    Contributors:


    Publication date :

    2017




    Type of media :

    Article (Journal)


    Type of material :

    Print


    Language :

    English



    Classification :

    BKL:    52.30 / 52.52 / 52.52 Thermische Energieerzeugung, Wärmetechnik / 52.30 Strömungskraftmaschinen, Turbomaschinen




    Optimization methods for passive damper placement and tuning

    Milman, Mark H. / Chu, Cheng-Chih | AIAA | 1994



    Spinning and Azimuthally Standing Acoustic Modes in Annular Combustors

    Evesque, Stephanie / Polifke, Wolfgang / Pankiewitz, Christian | AIAA | 2003