SEGMENTED MIXING DEVICE HAVING CHEVRONS FOR EXHAUST NOISE REDUCTION IN JET ENGINES

摘要

Disclosed is a means for reducing jet engine exhaust noise wherein mixing is enhanced between adjacent exhaust flows and between exhaust flow and free-stream flow. The device does so with a very small degradation in aircraft performance. The device is a segmented, triangular or trapezoidal shaped, curved extension to a nozzle's sleeve that results in a serrated trailing edge. The nozzle extensions enhance the natural free mixing of the jet's exhaust flows and therefore reduce the acoustic energy associated with the velocity differences between the streams in which they are imbedded. The novel structure forces adjacent flows to penetrate into one another to a greater depth than that achievable with free mixing and results in a more uniform flow in a shorter stream wise distance while limiting high frequency noise through utilization of root radii in the order of 15 to 20% of the segment's width at the intersection of a parent nozzle.