You must know:

  1. Application type (Engine, Blower, etc.)
  2. Silencer model (Based on Designed DIL)
  3. Pressure drop (PDF) for the silencer
  4. Gas flowing temperature
  5. Silencer allowable pressure drop

What you must do:

  1. Select a silencer model based on required DIL
  2. Calculate maximum velocity (FPM)
  3. Compare calculated velocity (FPM) with recommended velocity limits.

The flow area through the silencer must be sufficient to pass the maximum flow without imposing excessive pressure drop.

All VANEC silencers have recommended velocity limits that are optimized for maximum insertion loss.

Exceeding these velocity limits will degrade the silencer performance due to the effects of flow noise (self noise). This method allows the user to select a silencer size based on the allowable pressure drop across the silencer and the gas flowing temperature. 

The following formula can be used to calculate an approximate maximum velocity that can be used to size the silencer.

Sizing for Flow​