Mechanism, prediction and control method of combustion instability in propulsion system

Thermoacoustic instabilities are characterized by large-amplitude oscillations for the interactions between acoustics and unstable heat releases. Such instabilities have been encountered in rockets engines, afterburners and gas turbines in the form of combustion instabilities. Sometimes it would bring structure damages. Review about investigations on Mechanisms and control method of the combustion instability is conducted. By now, a lot of work has been done on the mechanics of these instabilities, such as numerical and experimental investigations. The numerical investigations include one dimensional, three dimensional analytical thermoacoustic instability model, and LES on unsteady flame heat release. And experimental studies include rijke tube and real combustors, and so on. Under these investigations, the ultimate purposes are the effective control methods to the instabilities. By now, the control methods include passive and active methods. Active method is successful in theory but it has a long way to go to be applied in engineering because it always includes very complex executive system. The passive methods, such as Helmholtz resonator and perforated liner, have been widely used in practice.