AEROACOUSTIC ANALYSIS OF STRAIGHLT-THROUGH MUFFLERS WITH SIMPLE AND EXTENDED TUBE EXPANSION CHAMBERS.

Abstract

Among the various methods for eraluation of the performance of exhaust mufflers, the transfer matrix method is most handy. The transfer matrices for various elements of expansion chamber type of mufflers with simple area changes and extended tubes, relating the aeroacoustic variables across them, are derived from the Unearned equations of mass continuity, momentum balance and energy relations.The losses in stagnation enthalpy or pressure occurring at these elements art taken into consideration explicitly. The new transfer matrices are used in the theoretical prediction of noise reduction in experimental mufflers and a good agreement between the predicted and experimental values of noise reduction is observed.