Science and Technology of Energetic Materials

Vol.76, No.3 (2015)

Research paper

Acoustic emission characteristics of underwater pyrotechnic combustion from a feedback cavity
Jie Li, Hua Guan, Dongming Song, Qi Wang, and Jun Du


In order to research the acoustic radiation characteristics of underwater pyrotechnic combustion, a feedback cavity was introduced and the effects of its main structural characteristics on underwater acoustic radiation were studied by acoustic testing. The results show that the addition of the feedback cavity similar to a Hartmann acoustic generator significantly improved the sound pressure level (SPL) of underwater pyrotechnic combustion, especially the peak of SPL that was increased by 13 dB from 149 to 162 dB at the frequency of 125 Hz. But the addition of the feedback cavity had little effect on the frequency. These results indicated that the feedback cavity is effective for improving SPL in underwater pyrotechnic combustion. There was a change of 6.8 dB in the magnitude of the SPL at a frequency of 100 Hz as the charge nozzle diameter was increased from 10 mm to 15 mm. The frequency of the underwater pyrotechnic combustion changed slightly when the charge nozzle diameter or the feedback cavity diameter was increased.

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pyrotechnics combustion, underwater, acoustic emission characteristics

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