Results 61 to 70 of about 404,526 (210)

Study on Low-Noise Fan. Noise Reduction of Pusher-Type Condenser Cooling Fan.

TRANSACTIONS OF THE JAPAN SOCIETY OF MECHANICAL ENGINEERS Series B, 1993
In order to reduce the noise from a fan for an automobile condenser cooling system, air flow around a blade of the fan was studied by flow visualization and measurements of pressure fluctuations on the blade surface. The pressure fluctuations were found to depend largely on the turbulence intensity of the inflow and to increase the noise.
Kiyoshi Kawaguchi, Shigeru Kadota, Masahiko Suzuki, Kazuma Matsui, Koji Kikuyama   +4 more
openaire   +2 more sources

Acoustic and aerodynamic performance of a variable-pitch 1.83-meter-(6-ft) diameter 1.20-pressure-ratio fan stage (QF-9) [PDF]

Far field noise data and related aerodynamic performance are presented for a variable pitch fan stage having characteristics suitable for low noise, STOL engine application. However, no acoustic suppression material was used in the flow passages. The fan
Glaser, F. W., Lucas, J. G., Woodward, R. P.   +2 more
core   +1 more source

Avco Lycoming quiet clean general aviation turbofan engine [PDF]

, 1980
A fan module was developed using an existing turboshaft engine. The fan was designed using the latest in large engine noise control technology. A mixer was added to reduce the already low exhaust gas velocity.
Wilson, C. A.
core   +1 more source

Numerical and Experimental Investigations of the Sound Generation and Possible Optimization Techniques of Wires for Fan Guard Grilles

International Journal of Turbomachinery, Propulsion and Power
For modern axial fans optimized for low self-noise, additional noise emission from guard grilles mounted downstream of the fan can become one of the dominant sources of sound.
Sandra Hub, Frieder Lörcher
doaj   +1 more source

Three-dimensional effects on pure tone fan noise due to inflow distortion [PDF]

Two dimensional, quasi three dimensional and three dimensional theories for the prediction of pure tone fan noise due to the interaction of inflow distortion with a subsonic annular blade row were studied with the aid of an unsteady three dimensional ...
Kobayashi, H.
core   +1 more source

Propulsion systems noise technology [PDF]

, 1978
Turbofan engine noise research relevant to conventional aircraft is discussed. In the area of fan noise, static to flight noise differences were discussed and data were presented for two different ways of simulating flight behavior.
Feiler, C. E.
core   +1 more source

Acoustic testing of a 1.5 pressure ratio, low tip speed fan (QEP fan B scale model) [PDF]

A scale model (0.484 scale factor) of a single stage fan designed for a 1.5 pressure ratio and 1160 ft/sec tip speed was tested to determine its noise characteristics.
Kazin, S. B., Minzner, W. R., Paas, J. E.   +2 more
core   +1 more source

Predicting the audibility and annoyance of unducted fan engines [PDF]

Predictions of the prevalence of annoyance associated with aircraft noise exposure are heavily influenced by field studies conducted in urban airport neighborhoods.
Fidell, Sanford, Helweg-Larsen, Marie, Secrist, Linda   +2 more
core   +1 more source

Noise from turbomachinery [PDF]

A review is made of turbomachinery noise from turbofan engines as typified by fan noise. The mechanisms and theories of fan noise are reviewed and concepts for its reduction, including acoustic suppression are discussed. Correlations of the overall noise
Conrad, E. W., Feiler, C. E.
core   +1 more source

Acoustic test results from a 36 inch (0.914m) statorless lift fan with serrated and unserrated rotor blades [PDF]

Test results of the LF336/E statorless lift fan with serrated and unserrated rotor leading edges are presented. Fan broadband noise reductions from 2 to 5 dB were achieved in the forward quadrant at frequencies from 100 to 2500 Hz.
Stimpert, D. L.
core   +1 more source