Progress on forcing pulsation for acoustic, thermoacoustic or flow control purpose in a pressurised vessel by means of a siren: GT2020-16015

Fabrice Giuliani, Markus Stütz, Nina Paulitsch, Lukas Andracher

Research output: Chapter in Book/Report/Conference proceedingConference contribution


A siren is a robust fast-valve that generates effective flow
pulsations and powerful noise levels under combustor field conditions.
Its principle relies on a sonic jet sheared periodically
by a cogged wheel rotating at a given speed. Developed for
experiments in combustion stability, it offers an alternative to
loudspeakers when the use of these is made difficult because of
aggressive flow conditions (e.g. elevated conditions of pressure
and temperature, presence of impurities in the gas). While the
siren was designed for laboratory applications, its technology is
a promising candidate for effective flow control on gas turbine
fleets. By scanning through a given frequency range, one detects
the acoustic resonance of specific parts of the combustor assembly
and identifies a zone of combustion instability during a sensitivity
analysis where the flame is exposed to calibrated perturbations.
Regarding control applications, it can act out of phase for
damping purposes in the low-frequency domain (phase control),
or transfer the acoustic energy to a higher and less harmful subharmonic
(modal control). Since a chocked nozzle is involved,
the siren’s actuation is decoupled from the flow condition downstream,
which is convenient for control. Following-up to previous
works where a siren model was introduced with the capacity to
vary the amplitude of pulsation independently from the frequency
[GT2011-45071], this paper describes into details new features
as follows. First, the performance of the apparatus was improved
to visit frequencies in the 0-6 kHz range so that the operation
Address all correspondence to this author.
is extended to frequencies met by precessing vortex cores in a
burner or tangential instabilities in an annular combustor. Next,
the discharge configuration is tested and validated as an alternative
to the conventional blow-down operation with the siren
placed upstream of the pressurised test cell. There, the siren is
placed downstream of the test cell, deriving a small part of the
pressurised air in the plenum. Finally, a new calibration procedure
for fast pressure probes and accelerometers is presented
and tested. A multi-modal excitation is introduced where more
than one frequency peak is being produced and where the excited
frequencies create a kind of a chord. In conclusion the siren is
recommended as an effective flow controller, and as a broadband
and powerful calibrator.
Original languageEnglish
Title of host publicationProceedings of ASME Turbo Expo 2020: Turbomachinery Technical Conference and Exposition
PublisherAmerican Society of Mechanical Engineers(ASME)
Publication statusPublished - 22 Jun 2020
Externally publishedYes
EventASME Turbo Expo 2020: Turbomachinery Technical Conference & Exhibition - virtuell
Duration: 21 Sep 202025 Sep 2020


ConferenceASME Turbo Expo 2020

Fields of Expertise

  • Mobility & Production

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