VOF mass loss

Smaras · November 16, 2012, 10:39

Hello all,

I am doing VOF simulation with 2ddp. Now using two phase air and water. Taking water as first phase and air as second. With small inlet with 96 m/s air impingement over water surface. Lance to water bath distance is 154 mm with 100 mm depth of water bath and having 100 mm radius of cylinder. Outlet is at top defined as pressure outlet. Now the problem is that when i am doing calculation it's diverging but the results are totally disappointing as the penetration depth of the air jet should have reached 14 mm while it simulation its stuck at 7.5 and further there is a mass loss of around 0.1 Kg out of 3 Kg.
Have used coarser mesh and its showing better result. Now according to the theory the finer mesh should have given better result but here it's 180 degrees.

Would be thankful if some would give suggestions.

Regards,
Smaras

Smaras · November 16, 2012, 11:00

And further i am using URF as
pressure 0.2
momentum 0.3
Tur. dissipation rate 0.8
Tur. viscosity 0.8
Step size 0.0001

Non iterative with Factional Scheme
Volume Fraction = geo reconstruct
Turb. KE = quick

Regard & Thanks in advance

Smaras · November 20, 2012, 07:36

After even changing my Under relaxation factors. More finer mesh was simulated. But still mass loss is there.

Is there any one who can help in this regard.

Best Regards,
Smaras

November 16, 2012, 10:39	VOF mass loss	#1
Smaras Member Smaras Join Date: Sep 2012 Location: Germany Posts: 78 Rep Power: 14	Hello all, I am doing VOF simulation with 2ddp. Now using two phase air and water. Taking water as first phase and air as second. With small inlet with 96 m/s air impingement over water surface. Lance to water bath distance is 154 mm with 100 mm depth of water bath and having 100 mm radius of cylinder. Outlet is at top defined as pressure outlet. Now the problem is that when i am doing calculation it's diverging but the results are totally disappointing as the penetration depth of the air jet should have reached 14 mm while it simulation its stuck at 7.5 and further there is a mass loss of around 0.1 Kg out of 3 Kg. Have used coarser mesh and its showing better result. Now according to the theory the finer mesh should have given better result but here it's 180 degrees. Would be thankful if some would give suggestions. Regards, Smaras Last edited by Smaras; November 19, 2012 at 04:37. Reason: image re-size

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November 16, 2012, 11:00		#2
Smaras Member Smaras Join Date: Sep 2012 Location: Germany Posts: 78 Rep Power: 14	And further i am using URF as pressure 0.2 momentum 0.3 Tur. dissipation rate 0.8 Tur. viscosity 0.8 Step size 0.0001 Non iterative with Factional Scheme Volume Fraction = geo reconstruct Turb. KE = quick Regard & Thanks in advance

November 20, 2012, 07:36		#3
Smaras Member Smaras Join Date: Sep 2012 Location: Germany Posts: 78 Rep Power: 14	After even changing my Under relaxation factors. More finer mesh was simulated. But still mass loss is there. Is there any one who can help in this regard. Best Regards, Smaras