0.4" isn't impossible provided the face velocity is low enough. The pressure drop of a silencer is directly related to the free area of the baffles and the exit configuration. (ie Blunt, rounded, or flared)
A silencer for that application isn't an "off the shelf" unit. It typically is custom...
The ASHRAE Handbooks are a good resource.
- Applications Chapter 47 Sound and Vibration
- Fundamentals Chapter 7 Sound and Vibration
Most suppliers refer back to the ASHRAE handbooks, and rely on it as the standard for the industry.
I still cringe when I think about using the VB6 package & deployment wizard. I found the Visual Studio 6.0 Installer much friendlier to work with.
http://www.microsoft.com/downloads/details.aspx?FamilyID=5fbbc453-cd04-4562-a66e-5c21436e6f56&DisplayLang=en
The above link might work, if not...
When I was looking into migrating to VB.Net a couple years ago, I had found out it is possilbe to include the .Net framework into the application installation package. Of course the installation package then jumped around 30Mb or so.
I'm still looking into migrating...
Pat
If you use perf with a minimum free area of about 25% the the degradation of the acoustic performance will be negligible. However, film lining when behind perf can substantially degrade the performance of the insulation. Many silencers include a layer of spacing to ensure the film is kept...
Acoustics of Ducts and Mufflers by M. L. Munjal is the most comprehensive that I've come across
These two each have a chapter chapter on the topic of silencers, as well as other information
Engineering Noise Control by Bies and Hansen
Noise and Vibratation Control Engineering by Beranek and...
ANSI/ISA-S75-17-1989 Control Valve Aerodynamic Noise Prediction would be a good place to look.
There also is a section on valve noise in the Noise and Vibration Control Engineering: Principles and Applications by Beranek and Ver. It contains a simplified version of the above standard.
Hope...
