다공체를 이용한 모형 가스터빈 연소기의 열-음향 연소불안정 저감에 대한 실험적 연구

Abstract

Combustion instabilities are inevitable phenomena during the development and operation of propulsion and gas turbine. These instabilities are spontaneously exited by interactions of downstream and upstream perturbations on the feed-back loop. They cause several harmful effects such as disturbance of control system and damage to the parts of combustion chamber. The mechanisms responsible for exciting combustion instabilities are various depending on the combustion system. The studies carried out so far are mainly concerned with these mechanism and control to attenuate combustion instabilities. However, the inherent complexity of this problem prevents people finding a way to solve it. In this study, porous attenuation of combustion instabilities is experimentally investigated using model dump gas turbine combustor. Underlying mechanism of porous absorption is well established in acoustics. With this mechanism, the experiments is performed comparing stainless steel and SiC foam(20 ppi) dump plane as one of the passive control method about combustion instabilities. The results show the intensity of instabilities is attenuated in the overall range of frequency. Its effect depends on the location of porous material. Based on these results, we can state that porous attenuation mechanism works as efficiently as an alternative control method for combustion instabilities.