| 摘要 |
An aircraft engine has a nozzle shaped to reduce the volume of Mach diamonds being formed in the exhaust plume. A notch or recess is formed in the discharge edge of the nozzle. The recess provides a forward discharge edge that causes additional Mach diamonds to occur at a regular spacing from the forward discharge edge. These additional Mach diamonds are axially staggered with other Mach diamonds, which occur at regular spacing from the rearward edge of the nozzle discharge edge. Each Mach diamond has a volume that is substantially less than one-half the volume of a Mach diamond created by a conventional nozzle. This results in less high temperature areas per axial increment in the plume than the prior art exhaust plumes. Because Mach diamonds are the primary cause of high infrared emissions, as well as acoustic noise, a reduction in the total volume of Mach diamonds in the exhaust plume thus reduces infrared emissions, as well as the noise.
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