Noise suppressing turbofan nozzles and method
US4288984A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 19, 1978 |
| Grant date | Sep 15, 1981 |
| Priority date | — |
| Expiry date | Sep 19, 1998 |
Classification
- Technology area (CPC F)Mechanical Engineering; Lighting; Heating
- CPC primaryF02K1/44
- WIPO fieldEngines, pumps, turbines
- WIPO sectorMechanical engineering
Abstract
Noise perceived below a turbofan is reduced by providing a thicker fan flow below the turbofan primary exhaust flow than is present in conventional turbofans having generally circular and concentric fan and exhaust flows. To thicken the fan flow, the exhaust nozzle is offset upward in the fan nozzle, or the exhaust nozzle discharge end is canted to offset the exhaust flow upward, or the exhaust nozzle is flattened to a generally rectangular or an elliptical shape having a major horizontal axis. In any of these cases, the thickness of the fan flow below the primary exhaust flow is increased and less noise is perceived below the turbofan than if circular concentric fan and exhaust flows were produced. In one embodiment a noise-suppressing thickened fan flow is used in combination with a conventional noise-suppressing multilobe or multitube mixing nozzle to further reduce noise perceived below the turbofan.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.