Investigation On Thermo-Acoutic Combustion Instability

The purpose of this experimental study is to identify the factors that give rise to combustion instability in case of premixed combustion and to develop a useful method to control it. The studied experimental device is a self-developed combustor,Measurements of chamber pressure and frequency have been performed. The result showed that the component concentration has very tremendous influence on the pressure frequency. As the air-consumed coefficient decreased, the frequency of pressure decreased too. When the frequency became low enough, the magnitude of the low frequency increased.We devised a new method to measure the heat release rate. Theory and practice test showed that the method was feasible. The research show that when the air-consumed coefficient decreased, the frequency of heat release rate decreased too. Comparing the frequency of heat release rate with pressure frequency show that they had are almost same.Two means were tried in controlling the instability. The one is active method and the other is passive. The passive method showed a good result. Whereas the serviceability of the passive method is poor, we did not pay much attention to it. The active means did not work. We analyzed the reason, and gave some good advices.