中文摘要：

对多孔介质稳焰机理以及预混火焰发生动力学失稳的原因进行了理论分析,并利用振动噪声分析仪和高速摄像仪研究了贫燃、贫氧预混火焰发生热声不稳定时燃烧室内的声压振荡特性及火焰热释放的脉动规律.当化学当量比Φ≥1.24时,贫氧预混火焰因连续点火源消失而发生动力学失稳;当Φ≤0.80时,贫燃预混火焰则因预混可燃气流速与火焰传播速度之间平衡关系被破坏以及局部猝熄等原因而失稳.当贫氧预混火焰发生热声耦合振荡时,燃烧室内的压力振荡特征频率及最高振荡幅值均较低,分别为9.02Hz和80dB;而当贫燃湍流预混火焰发生热声振荡时,燃烧室内的压力振荡特征频率为127.07Hz,声压级最大振幅高达115dB.图像分析显示,火焰热释放的脉动与声压振荡是频率相同、相位相近的.

英文摘要：

Structures and dynamic instability of premixed flame stabilized by porous media were discussed in this paper.The thermo-acoustic oscillation characteristics of lean premixed flame and lean oxygen premixed flame,including pressure and heat release,were studied using noise-vibration analyzer and high-speed camera.When the global equivalence ratio Φ ≥1.24,combustion oscillation occurs to lean oxygen premixed flame because of the dis-appearance of continuous lighter.When the global equivalence ratioΦ ≤ 0.80,combustion instability of lean pre-mixed flame occurs,which is caused by local quench and the imbalance between flame propagation velocity and premixed gas velocity.As to lean oxygen premixed flame,thermo-acoustic oscillations occur at the frequency of 9.02 Hz,and the corresponding power level is 80 dB.As to lean premixed flame,the characteristic frequency is127.07 Hz and the corresponding power level is115 dB.Image analysis results show that the frequency and phase of heat release are the same as those of sound pressure.