声波对锥形预混火焰表面温度脉动的影响

在燃气轮机燃烧室中，当不稳定的燃烧过程与声波相互耦合时，就会产生自激的振动。文中主要研究甲烷-空气预混锥形火焰对声波扰动的响应。采用精细热电偶测量火焰的温度脉动。在没有声波扰动时，火焰表面温度出现20Hz的特征频率。在施加50Hz声波扰动后，火焰的表面的温度出现50Hz、25Hz、100Hz和150Hz的特征频率。施加其它频率的声波扰动时，火焰出现类似的现象。预混火焰对声波扰动的谐波、分谐波和高阶谐波响应并存。

RESPONSE OF CONICAL PREMIXED FLAME SURFACE TEMPERATURE FLUCTUATION TO ACOUSTIC PERTURBATION

Self-sustained oscillation will appear in gas turbine combustor when unstable combustion couples with acoustic. The response of methane-air conical premixed flame to acoustic perturbation was investigated. A fine thermocouple was used to measure the temperature fluctuation of the flame. Fluctuation of flame surface temperature had a main frequency of 20Hz without acoustic perturbation. When 50Hz acoustic perturbation was added, 50Hz, 25Hz, 100Hz and 150Hz frequency of temperature fluctuation appeared. The similar phenomena was found when other frequencies acoustic perturbation was added. The harmonic, sub-harmonic and multi-harmonic response of the premixed flame to acoustic perturbation was observed.