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Noise comparison of two 1.2-pressure-ratio fans with 15 and 42 rotor blades
| Content Provider | NASA Technical Reports Server (NTRS) |
|---|---|
| Author | Glaser, F. W. Woodward, R. P. Wazyniak, J. A. |
| Copyright Year | 1973 |
| Description | Two 1.829-m-(6-ft-) diameter fans suitable for a quiet engine for future short-takeoff-and-landing (STOL) aircraft were compared. Both fans were designed for a 1.2 pressure ratio with similar weight flows, thrusts, and tip speeds. The first fan, designated QF-9, had 15 rotor blades and 11 stator blades. The rotor was highly loaded and the tip solidity was less than 1. The QF-9 rotor blades had an adjustable pitch feature which can be used for thrust reversal. The second fan, designated QF-6, operated at a moderate loading with a rotor tip solidity greater than 1. Fan QF-6 had 42 rotor blades and 50 stator blades. The low number of rotor blades for QF-9 reduced the frequency of the blade-passage tone below the range of maximum annoyance. In addition to this difference, the QF-9 fan had a somewhat smaller rotor-stator separation than the QF-6 fan. In terms of sound pressure level and sound power level, QF-9 was the noisier fan, with the power level results for QF-9 being about 1 db above those for QF-6 at equivalent operating points as determined by similar stage pressure ratios. At the same equivalent operating points, the maximum perceived noise along a 152.5-m (500-ft) sideline for QF-9 was about 2.5 PNdb below that for QF-6, which indicated that QF-9 was less objectionable to human hearing. |
| File Size | 5911316 |
| Page Count | 77 |
| File Format | |
| Alternate Webpage(s) | http://archive.org/details/NASA_NTRS_Archive_19730023876 |
| Archival Resource Key | ark:/13960/t0ms8gw8n |
| Language | English |
| Publisher Date | 1973-10-01 |
| Access Restriction | Open |
| Subject Keyword | Propulsion Systems Acoustic Measurement Engine Noise Rotor Blades Turbomachinery Noise Reduction Turbofans Rotor Stator Interactions Short Takeoff Aircraft Aerodynamic Loads Sound Pressure Ntrs Nasa Technical Reports Server (ntrs) Nasa Technical Reports Server Aerodynamics Aircraft Aerospace Engineering Aerospace Aeronautic Space Science |
| Content Type | Text |
| Resource Type | Technical Report |
