电站锅炉声学测温声源研究

Study on Sound Source in Acoustic Pyrometry of Boiler Furnace

电站锅炉的温度测量一直是实现炉膛火焰监测和燃烧控制的热点和难点。新兴的声学法应运而生,实现了炉膛温度在线、非接触式的测量。电站锅炉声学测温的研究中,声源作为测量时延的主要因素,因此声源的选取尤为重要。以声学测温中声源的选择为目的,采用互相关时延估计法,在实验室环境下,对不同的声源信号进行了研究。结果表明,电声源比起气动声源,其构造简单,安全稳定,技术相对成熟,如何提高其声压级是今后研究的重点;声源信号的发声频率500～3 000 Hz为宜;扫频信号、MLS序列、冲激函数等信号都可以作为声源信号,其中要获得准确的时延估计,扫频信号需要较小的扫频周期和较宽的扫频频带;使得声学测温声源信号的选择多样化,为声学测温进一步开展提供了重要的参考。

Furnace flame monitoring and combustion control is a hot spot and the difficulty of power station boiler temperature measurement. Emerging acoustic method arises at the historic moment, realized the furnace tempera- ture online and non-contact measurement. In the study of power station boiler acoustic temperature, source is the main factor of measuring time d~,lay, so the selection of the sound source is particularly important. For the purpose of selection for sound source in acoustic pyrometry of boiler furnace, the study on different sound source was done which employed the correlated time delay estimation under the environment of lab. The results indicate that electric source has a simpler structure than the pneumatic source, is more safe and stable, and the technology is more ma- ture. The key to the study is how to increase the SPL of acoustic source. The frequency range should be from 500 Hz to 3 000 Hz. Frequency sweep signal needs smaller sweep cycle and a wide sweep frequently belt. They can be used as sound source signal such as chirp signal, MLS, impulse signal and so on which diversify the sound source signal and provide important consultation for acoustic pyrometry.