multihole orifice plates how to calculate the noise level

[Mikeydo]

When using a multiholed orifice plate. How can you calculate the noise level (dba). I can calculate the noise for one hole. But, I haven't got a clue how to calculate for multiple holes.

Any suggestions.

 

[Yobbo]

Acoustics is not my speciality. If however there is reason to be able to assume, that the individual holes could be considered as parallel in the sense, that they do not influence one another, you could add up the individual noise levels logarithmically.
Example: 1 source produces 20 dBa

3 sources will produce 10*log( 3*10^(2)) = 24,8 dBa.

In your case you should ofcourse consider the fact, that the flow will be divided over all the holes. I do not know whether that works lineairly or not. I hope this helps.

Karel Postulart, The Netherlands
Nuon Power Generation

 

[Mikeydo]

Thank you for your response. But, I think the noise level actually is decreased due to the multiple holes cancelling out each other. I just don't know how to calculate this.

 

[C2it]

Not so sure about this ..... it is a problem of coincident sound waves. They could be additive just as easily as cancelling ? If additive, why logarithmic and not linear ?

 

[dcasto]

just look at the Fisher noise reduction site.

http://www.emersonprocess.com/fishe...oduct_Solutions/Noise_Demo/English/index.html

the third video will help you.

 

[imok2]

This may also be useful for your problem

http://www.aplusflowtek.com/_papers/PPR-601 Instrumentation Symposium Presentation 1-2006 B.pdf