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Show A paper to submit for presentation at the Pacific Run International Conference on Environnlental Control of Combustion Processes Noise Caused by Turbulent Flames Toshisuke HIRANO, Takashi TSUfl,UDA, and Ritsu DOBASHI The University of Tokyo Abstract This paper prcsen ts reccn t im po rtan t resu l1.s on the In echan isms of nOlse gencration froin turbulent flames. Experimental results using a small turbulent flame burner show that the sound int ~ n sity in crease is mainly observed in the range of frequencies less than 2 kHz. The sound intensity in this region is shown to be clos 1)' related to the burning and gas velocities. This result coincides fairly well with a theoretical one based on a simple model. Based on these results, the lnechanisms of noise gcneration from turbulent flames are discussed . INTRODUCTION In general, a combustion equipment emits sound, which irritates people, makes annOYIng or even hurts eardrums. There are many sources of sound in a combustion equipment. Among them, combustion noise, which is caused by turbulent combustion in the equipment, is known as "combustion roar". Suppression of this combustion nOIse has been required for the improvlnent of public environments. For fulfilling this requirement, understanding of the emission mechanisms of the combustion noise is needed to explore. A n u 111 ber of studies ha.ve been carried ou t on acoustic phenomena associated with flame'S . Based on the theoretical evaluation by Ligh thill on the nOlse emISSIOn frOln non-react.ive turbulent flows[l,2]' I3ragg tried to explore the nOIse emISSIon from reactive turbulent flows[3J . In this study, he estinlated the efficiency to be 10-6. In the process of this efficiency estinlatiol1 , however, several |
