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

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.