电站锅炉声学测温中炉膛声场及热态背景噪声特性研究

Study on characteristic of sound field and hot-state background acoustic noise in boiler furnace of acoustic pyrometry

以理论和实验相结合的方法,对锅炉冷态声场进行了研究;系统分析了锅炉热态噪声的产生机理和声衰减特性;把小波理论引入到炉膛声特性提取之上,从不同尺度空间获得了炉膛噪声信号的特性;并对背景噪声声压级进行了测量。研究表明:电站锅炉声学测温中,声源在锅炉冷态时形成的声场为扩散声场;热态由于声衰减作用可以近似为自由声场;不吹灰时,锅炉背景噪声能量集中在600 Hz以下的低频段,其概率分布为高斯分布;声压级稳定在113～120 dB左右。

With the combination of theoretical analysis and experiment,the cold state sound field was discussed in this paper.At the same time,the mechanism of formation of hot state acoustic noise and acoustic attenuation were systematically analyzed.The method of wavelet analysis was introduced into feature extraction of acoustical characteristics in boiler furnace,meanwhile the SPL of the background sound was measured.Research indicates that the cold state acoustic field is diffuse field and the hot state sound field approximates to free field due to attenuation.The energy spectra of background acoustic noise mainly concentrate in low frequency band below 600 Hz and the SPL is about between 113 and 120 dB without blowing.The probability distribution of noise is Gaussian.It also provides important consultation for acoustic pyrometry in boiler furnace.