Stabilization of acoustic modes using Helmholtz and Quarter-Wave resonators tuned at exceptional points

Abstract

Acoustic dampers are efficient and cost-effective means for suppressing thermoacoustic instabilities in combustion chambers. However, their design and the choice of their purging air mass flow is a challenging task, when one aims at ensuring thermoacoustic stability after their implementation. In the present experimental and theoretical study, Helmholtz (HH) and Quarter-Wave (QW) dampers are considered. A model for their acoustic impedance is derived and experimentally validated. In a second part, a thermoacoustic instability is mimicked by an electro-acoustic feedback loop in a rectangular cavity, to which the dampers are added. The length of the dampers can be adjusted, so that the system can be studied for tuned and detuned conditions. The stability of the coupled system is investigated experimentally and then analytically, which shows that for tuned dampers, the best stabilization is achieved at the exceptional point. The stabilization capabilities of HH and QW dampers are compared for given damper volume and purge mass flow.

arXiv comment34 pages, 19 figures, acepted in the Journal of Sound and Vibration

References in corpus (6)

• Observation of non-Hermitian degeneracies in a chaotic exciton-polariton billiard
• Reversing the Pump-Dependence of a Laser at an Exceptional Point
• Coupling of eigenvalues of complex matrices at diabolic and exceptional points
• Non-Hermitian Acoustic Metamaterials: the role of Exceptional Points in sound absorption
• Exceptional points in the thermoacoustic spectrum
• Exceptional points in coupled dissipative dynamical systems

Cited by in corpus (4)

• Degenerate perturbation theory in thermoacoustics: high-order sensitivities and exceptional points
• Acoustic Bound States in the Continuum in Coupled Helmholtz Resonators
• Experimental observation of exceptional points in coupled pendulums
• BOATS: Bayesian Optimization for Active Control of ThermoacousticS