Bauzer Medeiros E., Campolina França G., Silveira C.

Discharge lines are commonly found in industrial compressed air installations. Direct venting to the outside environment would produce unacceptable noise levels. Well-designed discharge lines employ silencers which reduce this effect to more acceptable levels. In the present study a series of scaled down experiments have been carried out for a typical blow off silencer. Compressed air with controlled pressure and flow was supplied to a line equipped with a termination silencer. The internal geometry of the so-called acoustic core has been varied and a series of experiments have been carried out for several flow and pressure conditions. The noise attenuation for each condition has been evaluated for a set of standard octave bands and associated with the corresponding fluid losses obtained at the output. The objective has been to associate acoustic efficiency with reduced pressure losses, which are not only detrimental in terms of efficiency but also increase line supply costs. Finally, overall efficiency is used as a useful tool in the design process of typical venting silencers.