电站锅炉声学测温中扫频信号声源特性研究

Characteristic Analysis of Chirp Signals for Temperature Measurement of Power Boilers Using Acoustic Pyrometry

为了对电站锅炉声学测温中的声源进行选择,借助冷态实验台对扫频信号进行了试验研究,并在国内某300 MW锅炉上进行了热态试验.为了确保其准确性,同时利用热电偶进行了热态温度标定.结果表明：线性扫频信号适合作为电站锅炉声学测温中的声源信号;500~3 000 Hz频率段的扫频信号作为声源最为适宜;扫频信号的频率区间越小,互相关时延估计效果越差;扫频周期取0.1 s最为合适;线性扫频信号成功地在300 MW锅炉声学测温系统中得以应用,可为电厂锅炉声学测温的研究提供重要的参考.

An experimental study has been conducted in a cold-state test rig to analyze the characteristics of chirp signals for temperature measurement of power plant boilers using acoustic pyrometry,while a series of hot-state experiments carried out on a 300 MW boiler.For comparison purposes,the gas temperature was simultaneously measured with an armoured thermocouple.Results show that the linear chirp signal may be taken as sound source signal for temperature measurement of power plant boilers,of which the optimum frequency range is found to be 500-3 000 Hz;the narrower the frequency range,the worse the estimation results of time delay by cross-correlation algorithm;the most appropriate cycle of frequency sweeping is 0.1 s.The proved application of linear chirp signal in acoustic pyrometry system of a 300 MW boiler may serve as a reference for future study of acoustic pyrometry for power plant boilers.