In aero engines, noise absorption is realised by acoustic liners, e.g., Helmholtz resonator (HR) liners, which often absorb sound only in a narrow frequency range. Due to developments of new engine generations, an improvement of overall acoustic damping performance and in particular more broadband noise absorption is required. In this paper, a new approach to increase the bandwidth of noise absorption for HR liners is presented. By replacing rigid cell walls in the liner’s honeycomb core structure by flexible polymer films, additional acoustic energy is dissipated. A manufacturing technology for square honeycomb cores with partially flexible walls is described. Samples with different flexible wall materials were fabricated and tested. The acoustic measurements show more broadband sound absorption compared to a reference liner with rigid walls due to acoustic-structural interaction. Manufacturing-related parameters are found to have a strong influence on the resulting vibration behaviour of the polymer films, and therefore on the acoustic performance. For future use, detailed investigations to ensure the liner segments compliance with technical, environmental, and life-cycle requirements are needed. However, the results of this study show the potential of this novel liner concept for noise reduction in future aero-engines.


    Access

    Download


    Export, share and cite



    Title :

    Experimental Study of Advanced Helmholtz Resonator Liners with Increased Acoustic Performance by Utilising Material Damping Effects


    Contributors:

    Published in:

    Applied Sciences ; 8 , 10 ; 1923


    Publication date :

    2018-10-15



    Type of media :

    Article (Journal)


    Type of material :

    Electronic Resource


    Language :

    English




    Double Degree of Freedom Helmholtz Resonator Based Acoustic Liners

    Gautam , Abhishek / Celik, Alper / Meek, Harry et al. | AIAA | 2021


    Modeling of Advanced Helmholtz Resonator Liners with a Flexible Wall

    Kohlenberg, Fleming / Schulz, Anita / Enghardt, Lars et al. | AIAA | 2023


    Acoustic Damping of a Helmholtz Resonator with an Oscillating Volume

    Zhao, Dan / A'Barrow, Chris / Morgans, Aimee et al. | AIAA | 2008


    Acoustic Damping of a Helmholtz Resonator with an Oscillating Volume

    Zhao, D. / A'barrow, C. / Morgans, A. S. et al. | AIAA | 2009


    Acoustic performance of a Helmholtz resonator with flow

    Kim,H. / Selamet,A. / The Ohio State Univ.,US | Automotive engineering | 2011