The acoustic response of reacting sprays in cross flow models to forced excitations

Pascal Gruhlke, Enric Illana Mahiques, Jürgen Meisl, Peter Kaufmann, Andreas Kempf, Jim B.W. Kok

    Research output: Chapter in Book/Report/Conference proceedingConference contributionAcademicpeer-review

    Abstract

    Thermo-acoustic instabilities can occur in combustion systems due to unsteady heat release. The derivation of transfer functions is a method to describe the systems dynamics, which is applied to analyse and to control these instabilities. In this work, validated models for spray atomization, evaporation and combustion in OpenFOAM are used to investigate their response to acoustic forcing. Mono-frequency excitations are employed, with a frequency range from 100Hz to 1000Hz in 100 Hz intervals. The fuel considered in this study is hexadecane, for which a reduced kinetic mechanism is available. A primary atomization model, together with a secondary atomization model, is employed to simulate a spray in cross flow. The evaporation model is a zero-dimensional model developed for multicomponent droplets at high ambient pressures and temperatures. The combustion model comprehends a blend of the FGM (Flamelet Generated Manifold) and the SCRS (Simple Chemical Reaction System) models. The acoustic response of each model, in terms of its transfer function, is determined by applying forcing at the inlet boundary. The penetration and global SMD are monitored at 80 mm downstream from the injection point and forcing frequencies are clearly found in the response of both quantities. The rate at which the droplet diameter shrinks is tracked in the droplet vaporization, and a non-linear response is encountered due to its dependence on the relative velocity. Similarly, the heat release is used for 1-D premixed flames, showing forcing frequencies in the model response too.

    Original languageEnglish
    Title of host publicationICSV 2016 - 23rd International Congress on Sound and Vibration: From Ancient to Modern Acoustics
    PublisherInternational Institute of Acoustics and Vibrations
    Number of pages8
    ISBN (Electronic)9789609922623
    Publication statusPublished - 2016
    Event23rd International Congress on Sound and Vibration, ICSV 2016: From Ancient to Modern Acoustics - Athens, Greece
    Duration: 10 Jul 201614 Jul 2016
    Conference number: 23

    Conference

    Conference23rd International Congress on Sound and Vibration, ICSV 2016
    Abbreviated titleICSV
    CountryGreece
    CityAthens
    Period10/07/1614/07/16

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