预混火焰诱导里克管热声振荡实验

Experiment of thermoacoustic oscillation phenomenon in Rijke tube induced by premixed flame

为了探究热声振荡现象中各物理量的变化规律,采用单端可调谐激光吸收光谱技术对火焰的温度进行了测量,测量频率为5 kHz,揭示了热声振荡中温度的变化规律。在里克管中,温度以大约230 Hz的频率规律性变化,变化频率与里克管的本征频率接近。里克管出口处的静压监测表明静压与温度在同一频率变化。此外,采用高速相机对火焰化学自发光进行了测量,火焰化学发光强度及发光面积在静压的影响下,也在周期性波动。温度、静压、化学发光强度三者波动频率保持一致。

In order to investigate the properties of various physical parameters in the thermoacoustic oscillation in the Rijke Tube, the flame temperature was measured by single-end tunable diode laser absorption spectroscopy(TDLAS), at the TDLAS measurement frequency of 5 kHz, which effectively revealed the properties of temperature in thermoacoustic oscillation. Result showed that,the temperature varied regularly at approximate 230 Hz,which coincided with the eigen frequency of the Rijke tube. The static pressure at the exit of the Rijke tube fluctuated at the same frequency. Besides, the flame chemiluminescence intensity was captured by the high-speed camera. The result showed that the flame chemiluminescence intensity area also fluctuated periodically due to the variation of static pressure. The frequencies of temperature, static pressure and chemiluminescence intensity were consistent with each other.