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Neser February 2, 2004 09:56

mass balance
Dear all, I am a new user for CFX 5.6. I want to make a mass balance in my system. How can I do this.

Glenn Horrocks February 3, 2004 19:16

Re: mass balance
Hi Neser,

I don't know what you mean. Do you mean you want to satisfy mass continuity? If that is what you are trying to do then it is already part of the Navier-Stokes equations, so is already taken care of. A converged solution will have the mass balanced (to within a fine tolerance)


Neser February 4, 2004 08:35

Re: mass balance
ok, I spray a liquid (have an amount of water) throgh a nozzle. The sprayed liquid will in direct contact with a hot air. As result, some water vapour will be evaporated from the liquid to the hot air. I want to know the amount of this evaporated water.

Glenn Horrocks February 4, 2004 19:52

Re: mass balance
Hi Neser,

So you want to model evaporation of a water spray, and find out how much water remains liquid and how much goes to vapour.

It sounds like you want to use particle tracking to monitor the water droplets, and include phase change on the droplets to model the evaporation. I don't think CFX5.6 supports this combination. CFX5.6 can do particle tracking, or it can do multiple phases with evaporation between phases, but not both. I don't do any multiphase stuff so I am no expert on the field (but hopefully what I've said is correct). Maybe you'll have to change your model to use the existing evaporation model or wait until CFX5.7

Regards, Glenn

Neser February 5, 2004 12:38

Re: mass balance
thank you for reply

Tracking the particles is not my goal. I only need to know the total amount of liquid that will evaporate.

as you can see in the picture linked to above, I need to find out the amount of water vapour lost either to the drain (liquid) or gained to the hot air.

Glenn Horrocks February 5, 2004 19:22

Re: mass balance

You should be able to model this in CFX5.6 using the Eularian-Eularian multiphase model, including the evaporation.


Amit Katiyar February 14, 2004 01:29

Re: mass balance
hi Neser,

Actually I also want to do some thing very similar to your case but still hanging because either I am not properly aware with the capabilities of CFX or it is difficult incorporate such physics in CFX. By the way my case is slightly simpler. You plz tell me how far you have gone in this work. I will seek some suggestions from you. regards Amit

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