Abstract:

Thermo-acoustic instability is a common problem occurring in the combustion chamber and is mainly caused by pressure perturbation and unstable heat release. This study demonstrates a design of a side-branch bypass to improve the thermo-acoustic stability in the simplest Rijke tube configuration by releasing the build-up energy. The bypass interconnects the main tube with the exterior via thin membranes that can release the pressure perturbation to the exterior while preventing flow leakage. The goal is to achieve a broadband performance that keeps efficiency under varying thermoacoustic working conditions. Compared with the conventional Helmholtz resonator arrays with similar dimensional constraints, the device can achieve good sound absorption performance at low frequencies, which means that the low-order modes of thermoacoustic instability can be well suppressed. In this presentation, the parameters studies and model analysis will be briefly introduced, and then some preliminary results of simulations and calculations will be presented.