Analysis of Combustion Induced Noise of Engine by Single Explosion Excitation : 2nd Report, Application of Transmission-radiation Coefficient to Running Engine

Combustion impact is one of the most predominant sources of engine noise. The transmission-radiation coefficients of combustion noise, which were defined as a conversion power ratio from the combustion impact to the emitted noise, were studied with both a stationary engine excited by a single explosion and an operating engine. The characteristics of these coefficients obtained in the same engine coincided with each other, so it can be said that the transmission and radiation of combustion noise of an operating engine are analogous with those of a stationary engine, to a certain extent. Then, the vibration response for combustion impact and the noise radiation coefficients were examined for each engine wall to identify their contribution to the total combustion noise.