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# TOUGH-HYDRATE - Problems with the maximum mass fraction of methane in aqueous phase

I'm trying to equilibrate a sloping system, containing a AqH phase and a Aqu phase. If methane mass fractions of methane in water are not maximum, hydrate phase dissolves. So, I want TOUGH-HYDRATE to set the maximum mass fraction of methane values in single aqueous phase. To do that I specify a high value for X_mA, than TOUGH calculates the maximum value and replaces the original value to the maximum:

THE SINGLE-PHASE CONDITIONS SPECIFIED AT ELEMENT "  1 1   " ARE ERRONEOUS

At T =  1.92981E+01 C, the CH4 mass fraction in H2O "X_mA" = 9.50000E-01 exceeds the maximum =  5.99297E-03 (T-dependent)

!!! ACTION TAKEN: SET X_mA = Max   ==>   EXECUTION CONTINUES

Ok, but after that, TOUGH says that this value is wrong, prints a different value for the maximum mass fraction of methane in water and stops execution:

!!!!!! "Phase1_Aqu_Eql": Gas phase evolves at element "  1 1   " ==> P =  8.35121719E+06  Peq_Hydr =  2.69476647E+07  X_mA =  5.99297481E-03  X_mA_max =  1.85578449E-03

!!!!!!!!!!   Routine Phase1_Aqu_Eql: ERRONEOUS DATA INITIALIZATION   ==>  STOP EXECUTION <<<<<<<<<<

Why does this happen? Do I have to change something in the code? I use the licenced version 1.0.

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• I suggest you begin the simulation again, but give a value of 1.855e-3 to the mass fraction (i.e., just a bit lower than the one the code gives you). Try it and let me know. If it does not work, please send me your input files.
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• With this value, it works. But the problem is that I have a big grid, so I it's hard to give all values manually (these two messages appear for all the cells setted to have aqueous phase).

I have a version of the simulator from a course that sets the mass fraction to 99% of the maximum mass fraction and it works properly. But this version has a limit of 3000 cells, less than what I need to use.

With the licensed version, I think the problem is not only setting the value to 99% of the maximum value (instead of setting to 100% of it) becouse the first message gives a value much bigger than the second one (5.99297E-03 in the first message and 1.85578449E-03 in the second one). When I setted the mass fraction value to 1.855e-3 for the cell 101, the second error message appeared for the cell 102, and so on...

The input file is attached.

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• And here, my output file too.

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• KHS
• HYDRATE
• KHS
• 4 yrs ago
• Reported - view

Cristiane are you still working with tough +

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• KHS Hi! no, I am not. maybe I still can help you. but I do not have much free time and might take a while to answer.

I read your comment about PetraSim. It is useful only for the generation of blocks ELEME and CONNE. Just copy the other blocks from a ready file and you will only have to change some few parameters accordingly to your needs.

Good luck! I agree with you when you say there is not much support here :/

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• KHS
• HYDRATE
• KHS
• 4 yrs ago
• Reported - view

aren't these sections already generated when you create mesh file?

petrasim can generate mesh easily, but it can't be exported to be used for running using tough+ hydrate..its in a different format...isn't it?

am I right?

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• KHS Hi! yes, they can be generated with MESH. I used PetraSim just because it was easier to visualize and to be sure I was fixing the primary variables on the correct blocks :)

I think the section of Petrasim was called only TOUGH+ and not TOUGH+HYDRATE. Or maybe I used the TOUGH2 section. I can't remember, sorry. But if you can use MESH, just use that, no need for Petrasim. You can not visualize results on it either, you will need TecPlot.

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• Cristiane Romio can we visualize the mesh that is made by MM using any software?

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• KHS
• HYDRATE
• KHS
• 4 yrs ago
• Reported - view

Cristiane Romio i need your help.