Low noise blades for axial flow compressors
US4012172A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 10, 1975 |
| Grant date | Mar 15, 1977 |
| Priority date | — |
| Expiry date | Sep 10, 1995 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY02T50/60
- WIPO fieldEngines, pumps, turbines
- WIPO sectorMechanical engineering
Abstract
A rotor blade configuration is disclosed which greatly reduces noise generated by the low pressure compressor, or fan, of a turbofan engine. The leading edge of the blade is swept forwardly from its hub up to a point of sweep reversal and then swept rearwardly to the tip of the blade. The slope of the curved leading edge line relative to the direction of airflow is gradually decreased from the hub to the tip to maintain the velocity component, of air relative to the blade leading edge, subsonic, while the relative velocity of the air to the blade is above a critical value and supersonic. This substantially eliminates noise producing, standing shock waves along the blade leading edges. Also described are methods for determining the configuration of such blades to obtain these ends with a minimum increase in blade weight and a minimum blade bending and blade attachment stresses.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.