water hammer analysis 1

[chanel86]

Dear all,

i'm new engineer and need your help to make water hammer analysis i was reading a different document that discribe water hammer and devices to prevent or minimize her effect but i didn't find an easy procedure to do it.

please see attachad file :

it's the shematic of the system that i need to study.

how to select the best device ? and can surge anticipating valve replace Surge tank.

thank you in advance for your kind help.

chanel

 

[BigInch]

I wouldn't think you'll be needing a surge device, unless the pump is overpowered or you have a very high velocity. Is the velocity over 1.5 m/s at full flow? Doesn't look like it.

In any case, to model this accurately including the pump and F control valve you're going to need a computer program to do it right. Any surge pressure will depend on how fast the pump spins up or stops and how fast the FCV reacts to to the pump's action. You might also consider that the FCV fails and slams shut.

I think your 80/50 reducer is shown backwards.

http://virtualpipeline.spaces.msn.com

"What gets us into trouble is not what we don't know, its what we know for sure" - Mark Twain

 

[lamojai]

Have you thought about soft starts and stops on the pump controls? This will minimize or possibly eliminate the pump suddenly stopping and or starting at full speed. Decreasing the possibility of water hammer.

 

[chanel86]

thank you for you kind help .but i need to prouve to cousultant that we didn't need a surge tank and surge anticipating valve is enough in absance of soft starter.cause in this project he wants autotransformer strating.

Biginch please could you tell me what software to use to make the analysis.

and how to estimate time of respone of pump in case of quick power failure.

Best regards.

chanel

ModonGroup S.a.r.l

 

[bimr]

One would think that your application is too simple to model. If you select the correct components such as slow closing check valves, you will not have to worry about water hammer.

Here is an article that you can use to evaluate your system:

http://www.pumped101.com/waterhammer.pdf

The worst case analysis to consider will be power failure, with the pump stopping immediately.

http://www.valmatic.com/documents/SurgeControlinPumpingSystems.pdf

 

[BigInch]

Probably right, but simple or not, I don't think we even know the maximum pressure in this system, or the pipe maximum operating pressure. We don't know how close its running to maop under steady state flow.

http://virtualpipeline.spaces.msn.com

"What gets us into trouble is not what we don't know, its what we know for sure" - Mark Twain