1. acoustic dimensioning - GLAUNACH Vent Silencers
1. acoustic dimensioning - GLAUNACH Vent Silencers
1. acoustic dimensioning - GLAUNACH Vent Silencers
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SYMBOLS<br />
SYMBOL UNIT DESCRIPTION<br />
Φ ° orientation angle<br />
α<br />
10 -6 m/m·K<br />
C m/s speed of sound<br />
thermal expansion coefficient<br />
DIL dB dynamic insertion loss<br />
f Hz frequency<br />
THE SILENCER HANDBOOK<br />
Part IV | page 14 of 14<br />
L dB internal noise intensity acc. to API RP521<br />
∆l m thermal expansion<br />
∆L Φ dB direction correction<br />
∆L a dB air attenuation<br />
∆L b dB bottom attenuation<br />
L p dB sound pressure level<br />
∆L TF<br />
L r<br />
dB<br />
dB<br />
sound transmission factors<br />
(∆L Φ , ∆L a , ∆L b , ∆L rx , ∆L s and ∆L v )<br />
required / permissible noise level at the<br />
reference point<br />
∆L r dB noise level reduction by distance<br />
∆L rx dB area factor<br />
∆L s dB screening factor<br />
∆L v dB vegetation attenuation<br />
L w dB sound power level<br />
M kg/s mass flow capacity (of moving fluid)<br />
p 0 bar(g) pressure upstream of valve<br />
PR - pressure ratio<br />
Q a m³/s volumetric flow quantity (of moving fluid)<br />
r m distance<br />
R N reaction force<br />
S a m² free area at silencer outlet<br />
T 0 °C or K temperature upstream of valve<br />
v a m³/kg specific volume<br />
w a m/s blow-off velocity (of expanded gas)<br />
© <strong>GLAUNACH</strong> GMBH Edition 2010
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