Flame acoustic characterization of a coal water slurry (CWS) gasifier is an important information which can show the flame burning state and its flow characteristics.In order to better understand the burning characteristics of impinging flame and its effect on the gasifier

the four-nozzle impinging flame and two-nozzle impinging flame of the gasifier with different conditions were studied respectively.The statistical theory and Hilbert-Huang transformation were used to analyze the flame acoustic signals in time and frequency domains.The results showed that with the increase of fuel or oxygen

the rate of chemical reaction increased and the flame burned more and more intensely

but the stability of the flame became worse.And oxygen played a key role in the process.The standard deviation of four-nozzle impinging flame noise was greater than that of the two-nozzle impinging flame noise

but the change of the standard deviation was the reverse.It meant that the four-nozzle impinging flame burned intensely but stably.In the condition with a low ratio of CWS feed and oxygen

the noises of four-nozzle impinging flame were concentrated in the low-frequency bands below 45 Hz and the medium-frequency 45—100 Hz band

indicating that four-nozzle impinging flame was more stable.