water hammer simulation
water hammer simulation
(OP)
hi, i have to simulate a water efect (in this case is a hot-oil circuit impulsed by a pump) and i would like to know what are going on with the pipe when switch of the pump.
Can i simulate this phenomena wiht CFX?
REGARDS
Can i simulate this phenomena wiht CFX?
REGARDS





RE: water hammer simulation
I have done modelling of pump trips with this software and validated it against the same models written in Flowmaster and it gives good answers but needs to be used with care as if you get cavitation then the results are inaccurate after cavitation starts. The same is true of the expensive software I suspect - it's always best to design to prevent cavitation.
More info on my web site if you're interested - http://www.process-notes.co.uk
Regards,
Stuart
RE: water hammer simulation
RE: water hammer simulation
At my company most CFD calculations are based on CFX, but for transients we use custom-made programs based on analytical formulas. Anyway, the principle is always the same: water as compressible, wave propagation equations, energy conservation / dissipation equations, etc... = transient analysis!
If the need is to estimate waterhammer transients, with a global error of less than 10% but local errors which can reach 100% (i.e. you will only calculate avg wh pressure), you can rely on analytical formulas in my opinion...
RE: water hammer simulation
However, this program handles steady/transient/single phase/two phase flow with heat transfer and has empty subroutine blocks which you can use to manipulate valve, pump, etc. parameters as a function of time.
Although not user friendly, it cost about the same as a single AFT product with much more horsepower. It's engine was originally developed by NASA, I believe.
Hope this presents a useful option for you.