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Evaporation due to Heat Transport using InterFoam (Correct Implementation?) 

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October 3, 2010, 04:10 
Evaporation due to Heat Transport using InterFoam (Correct Implementation?)

#1 
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Ovie Doro
Join Date: Jul 2009
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Hi,
I have tried to implement phase change due to evaporation for an incompressible liquid flowing down a vertical heated wall using interFOAM with an energy transport equation. I have employed the methods suggested by Bitan Shu (Phase Change Model for TwoPhase Fluid Flow Based on VOF Method) and Wondra et al. (Evaporation Model for Interfacial Flows Based on a Continuum Field Representation of the Source Terms). However in both cases, I am unable to accurately reproduce the results presented in their papers. I am particularly interested in Bitan Shu's implementation because it allows for large grid sizes. Has anyone successfully done this? If anyone has, please take a look at my code and tell me where I am wrong. Help is needed PLEASE! STEP 1: Solve the energy transport equation for the entire domain i.e. (both liquid and gas): STEP 2: Compute source terms using gradient of temperature: Code:
volVectorField gradAlpha = fvc::grad(alpha1); // to compute interface normal unit vector volVectorField nHat = gradAlpha/(mag(gradAlpha) + interface.deltaN()); // compute interfacial area = magnitude of grad(alpha1)*volume of cell volScalarField alpha1Prime = mag(gradAlpha); // set liquid and interfacial temperature to Tsat forAll(mesh.cells(), celli) { if (alpha1[celli] >= scalar(0.5)) { T[celli] = Tsat.value(); } // set this values to zero so that only liquid evaporation is accounted for if (alpha1[celli] < scalar(0.50)) { alpha1Prime[celli] = scalar(0); } } // Compute mass source field mDot = (kappa/evapEnthalpy)*(fvc::grad(T) & nHat)*alpha1Prime; // Compute energy source field using enthalpy of evaporation hDot = evapEnthalpy*mDot; evapEnthalpy = heat of vaporization rho1 = liquid density STEP 3: Solve alpha1 equation using MULES with source terms prescribed as Code:
Su = mDot/rho2; Sp = 0.0; STEP 5: Repeat STEP 1 Please kindly review and tell me where this is wrong. Suggestions on more correct implementation of the source terms for evaporation would be well appreciated. Thanks for the help. 

October 4, 2010, 02:21 

#2  
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Sabin Ceuca
Join Date: Mar 2010
Location: Munich
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Hi Ovie,
I am also struggling to implement temperature driven phase change. I tried the same as you did but my Su=mDot/rhoLiquid=HTC_liquid/rhoLiquid*(TsatT)/(latentHeat)*InterfacialAreaDensity. My Source term looks different because my phase change is due to condensation. My problems are that it crashes and I don’t get any reasonable results. What do you mean by ? Quote:
Sabin 

October 4, 2010, 02:44 

#3  
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Ovie Doro
Join Date: Jul 2009
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Hi Sabin,
Quote:
In the case of Bitan Shu's model, the simulation reports completely strange results. I really dont know where to start from at the moment. I am reading up another paper by P. Keller et al. (Numerical Simulation of Evaporating Droplets with Chemical Reactions using a Volume of FLuid Method) where they used interFoam and reported nice results. I think I might get some practical details on the implementation from there. Thanks.. 

October 4, 2010, 03:29 

#4 
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Sebastian Gatzka
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Location: Frankfurt, Germany
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As far as I know Shu used OpenFOAM in his Ph.D. thesis.
I'm sure you can get more informations out of if that of the paper. Try to get it!
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October 4, 2010, 16:21 

#5  
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Ovie Doro
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Hi Sega
Quote:
Thanks 

October 4, 2010, 17:35 

#6  
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Sebastian Gatzka
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Quote:
Please contact him directly: http://www.tecies.com/
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October 4, 2010, 17:40 

#7  
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Ovie Doro
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Quote:
Thanks... 

October 4, 2010, 17:46 

#8  
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Sebastian Gatzka
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Quote:
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October 4, 2010, 17:48 

#9 
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Ovie Doro
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Very well then.
Thanks for the help. 

October 6, 2010, 04:54 

#10 
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Nima Samkhaniani
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hi ovie
could you implement shu paper properly ? i tried it, i have used interPhaseChangeFoam , but my results can't follow interface exactly,please inform me about ur last effort!!!!! and i suggest you look at interPhaseChangeFoam and MULE code in it !!!! 

December 16, 2011, 08:02 

#11 
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Lars Kiewidt
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Ovie, by the way, I found that my results depend on the timestep. The larger the timestep, the more liquid is evaporating.


December 16, 2011, 08:10 

#12 
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Ovie Doro
Join Date: Jul 2009
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Well that comes down to your grid sizes and the size of your CFL number. In my case I used a well resolved grid (try the grid sizes specified in Wondra's paper) and specified variable time step in controlDict. The results were very comparable to those reported in Wondra's paper.


December 16, 2011, 10:44 

#13  
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Nima Samkhaniani
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Quote:
http://www.cfdonline.com/Forums/blogs/nimasam/906boilingopenfoam.html and here evapPhaseChangeFOAM 

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