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Vibrations due to pressure drop over orifice

Vibrations due to pressure drop over orifice

Vibrations due to pressure drop over orifice

(OP)
Hello everybody!
Do any of you have any tips on how to calculate vibrations caused by pressuredrop over an orifice?
It now seems that higher backpressure leads to heavier vibrations.
The flow is also fluctuating, reprociating pump.

Any tips on litterature would also be welcome!

Cheers,
Sai

 

RE: Vibrations due to pressure drop over orifice

Try asking this question in the fluid power or piping group.  Sounds like "flow induced vibration".

RE: Vibrations due to pressure drop over orifice

It sounds to me like "vortex shedding".

This is an unstable oscillatory flow condition set up when flow is interrupted by a blunt unstreamlined body in the flow path. It is what causes flags to wave or flutter in a breeze.

The faster the flow, the higher the frequency created in the wake. Some commercial fluid flow meters operate on this principle.

http://en.wikipedia.org/wiki/Vortex_shedding

RE: Vibrations due to pressure drop over orifice

Sounds more like cavitation to me due to the water boiling off. If it sounds like gravel passing that's what it is for sure. It shouldn't do much harm in that situation as it will probably be mid pipe where it collapses back.
A trick you see sometimes is to add a small amount of air after the plate.
   An orifice program should be able to calculate the noise (vibration) for you.

Roy

RE: Vibrations due to pressure drop over orifice

(OP)
Thank you!
Do you have any good orifice programs to recommend Roy?

Br,
Sai

RE: Vibrations due to pressure drop over orifice

Sai,
      I just had a look at one suggested by Mark Hill. It looks OK
Click on the blue button "Start Calculator"
http://www.flowmeterdirectory.com/flowmeter_orifice_calc.html
Faiing that most instrument suppliers have one for free e.g. Emmerson

Good Luck

Roy

RE: Vibrations due to pressure drop over orifice

(OP)
Ah, just what I needed :)
Gonna check it out now!

Br,
Sai
 

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