COMPACT MUFFLER APPARATUS AND ASSOCIATED METHODS

摘要

A muffler for attenuating core and turbine noise generated by a gas turbine engine is in the form of a housing of rectangular section spaced from and surrounding a duct defining a flow passage for the exhaust gases from the engine. The enclosed space around the duct and within the housing is divided into a number of acoustic attenuators with opposite sides of the duct each containing a reactive attenuator chamber and a resonant attenuator chamber within the first chamber at the downstream end. Opposite sides of the duct are perforated to provide acoustic communication between the passage on the one hand, and the downstream end of the reactive duct and the whole length of the resonant duct on the other hand. The reactive duct is a closed cavity whose dimensions and shape determine its acoustic characteristics while the resonant duct is in the form of a number of individual attenuating cells. The four attenuators are designed to attenuate sound primarily at different frequencies so that frequencies over a fairly wide range can be attenuated by a single muffler of compact construction. The reactive attenuators are designed to attenuate engine core noise while the resonant attenuators are designed to attenuate turbine noise.