Reciprocating internal combustion engines. Measurement method for exhaust silencers. Sound power level of exhaust noise and insertion loss using sound pressure and power loss ratio

2013 ◽  
Keyword(s):  
Power Loss ◽  
Measurement Method ◽  
Internal Combustion Engines ◽  
Sound Pressure ◽  
Power Level ◽  
Sound Power ◽  
Combustion Engines ◽  
Loss Ratio ◽  
Sound Power Level ◽  
Exhaust Noise

Study on Noise Control of Fan with Air Suction

2011 ◽  
Vol 138-139 ◽  
pp. 391-394
Author(s):  
Li Jun Wang ◽  
Zhi Yang Pan
Keyword(s):  
Power Loss ◽  
Noise Control ◽  
Power Level ◽  
Sound Power ◽  
Transmission Power ◽  
Fan Noise ◽  
Search Result ◽  
Sound Power Level ◽  
Pneumatic Device ◽  
Combine Harvester

Fan is a pneumatic device in the 4ZTL-1800 combine harvester threshing prior to cutting. Based on the prophase search result that fan noise is highest when fan rotates at 1200r/min, in order to decrease noise of it, sigle-microperferated-panel muffler, double-microperferated-panel muffler and interposition muffler were designed and tested. The results show that double-microperferated-panel muffler is best and sound power level of fan is decreased 11dB, and that interposition muffler is better, and that sigle-microperferated-panel muffler is worst to descrease fan noise. Through contrast on transmission power loss of different mufflers, cone-shaped double-microperferated-panel muffler is verified to be best for noise control of fan.

scholarly journals The Research of Acoustic Emission of a Low-Power Aircraft Engine

2018 ◽  
Vol 2018 (3) ◽  
pp. 14-25
Author(s):  
Michał Gęca ◽  
Konrad Pietrykowski ◽  
Karol Rosiński
Keyword(s):  
Sound Pressure ◽  
Power Level ◽  
Aircraft Engine ◽  
Sound Level ◽  
Sound Power ◽  
Research Model ◽  
Confined Space ◽  
Sound Power Level ◽  
Model Aircraft ◽  
Level Meter

Abstract This paper presents the methodology and investigation of the sound power level produced by a radial piston aircraft engine operating at varied speeds. The research model aircraft engine of a maximum power of 5.5 kW with a two-bladed airscrew was placed on a test bend. Its sound power level was calculated from the sound pressure level measured at 9 measurement points distributed on a hemispherical surface in a confined space in line with PN-EN 3744. Mean sound power generated by the ASP FS400AR engine is 96 dB at idle (2,880 rpm) and 105 dB at a cruising speed (4,740 rpm). Accordingly, it can be concluded that a sound level meter registered a higher sound power level at the points in front of the model aircraft engine than at the points behind it, whereas the lowest sound power level was registered directly above the engine.

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