バッフル板を用いた管群気柱共鳴現象の抑止法に関する研究(流体工学(流体計測I)

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In the present paper the attention is focused on the effect of baffle plates for controlling acoustic resonance which occurred in the two-dimensional model of boiler. There were three sets of in-line tube banks which installed rigidly in the model. We measured the sound pressure level, the phase delay of acoustic pressures and the gap velocity. As a result, we found many peak frequencies of SPL with different Strouhal numbers, mainly about S_t=0.15, 0.26 and 0.52. Using the node number of acoustic pressure mode in longitudinal and transverse direction, the resonant frequency of 185Hz (S_t=0.15) was (1,1) mode, 395Hz (S_t=0.15) was (1,2) mode and 765Hz (S_t=0.26) was (1,4) mode. The resonant noise at 765Hz (S_t=0.26) can be prevented effectively by inserting baffle plates dividing the duct width into four inside of a single set of tube banks. This acoustic resonance generated inside of tube banks. The resonant noise at 185Hz and 395Hz (S_t=0.15) can be prevented by inserting battle plates inside of the space between two sets of tube banks. These acoustic resonances generated inside of the space between two sets of tube banks.
2004-03-19