Engine noise
AssigneeROLLS-ROYCE plc
InventorsRory D. Stieger, Kevin M. Britchford, Paul J. R. Strange
Life of this patent
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Abstract
In order to provide noise suppression, bumps or undulations are provided on a nozzle surface in order to vary the convergent-divergent ratio between that surface and an opposed nozzle surface. By such an approach, a circumferential variation in the shock cell pattern is created and the flow is deflected so as to enhance turbulent mixing thereby suppressing noise.
Claims38
A nozzle for a gas turbine engine, the nozzle comprising a nozzle surface defining a plurality of undulations to vary in a circumferential direction, perpendicular to a jet flow direction, an available cross sectional area across the nozzle between the nozzle surface and an opposed surface of the nozzle over a desired convergent-divergent ratio range for noise control of the jet passing through the nozzle in use, wherein the undulations have amplitude in the range 0.1-2.0% of the nozzle exit diameter to attenuate shock cell noise.
Dependencies are inferred from the claim text.