Experiments and identification of thermoacoustic instabilities with the Rijke tube

This paper is concerned with the experimental characterization of a thermoacoustic demonstrator known as the Rijke tube. An approach which leverages the prior qualitative knowledge of the sys-tem's behaviour to plan the experiment campaign and identify reliable models of the system is described. First, nonlinear features of the dynamics, e.g. the type of Hopf bifurcation triggered by the thermoacoustic coupling and the periodic orbits arising from it, are investigated. Then, a family of linear systems, parameterized with a coefficient related to the heat release, is constructed. Different approaches for input design and identification are tested. The results show that the identified models can favourably complement the prior knowledge gained from first principles and provide quantitative assessments on the linear and nonlinear behaviour of the system.