Two-Phase Condensation Case
Please help me completing the pre-processing step for this simple case.
(**) No total temperature input is available. (***) No idea what size of droplets I have to put, because it is continuous fluid in reality. With those combinations the solution collapses.:( Could you allow me to get any hints to overcome troubles? I do not think CFX-v11 cannot handle such a simple two-phase calculation. Many thanks in advance. |
0) what do you want to do?
1) read the manual especialy on boundary conditions choices and code stability 2) switch the input BC for massflow and output BC for static pressure to get you started |
"Simple two-phase calculation"???!!! I don't think so! You are actually doing quite a difficult simulation and it does not surprise me you are having convergence problems. Condensation is a tricky process to model at the best of times.
You might want to consider using a Homogeneous Binary Mixture. Providing the phase change stuff can be treated as equilibrium this does a pretty good job of handling simple phase change. Is this approach valid for you? If your condensation is non-equilibrium then you can't use it. Whatever approach you use I guarantee it is going to be tricky to get working. Start simply with single phase flows and add the physical models one at a time making sure everything works before adding the next bit. Glenn Horrocks |
ghorrocks :
I appreciate your comments to let me realize my case is challenging. I will follow your suggestion, and if it doesn't work I will have to ask FLUENT people if FLUENT can solve the case. ckleanth : You seem to think I am trying to get gold without any effort. If you carefully look into details of CFX manuals for multi-phase parts, you will come to know how poor they are with providing insufficient knowledge. |
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I encountered the same problem,
I do not kown how to define the meterial of steam and water ? using constant propertity or using IAPWS Equation of State? and using Thermal Phase Change,how to define Saturation Temperature? thanks in advance!!! |
turbo:
have you workd out this difficult simulation? |
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Many thanks in advance! |
I do not understand your question. Can you say it again more clearly?
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CFX has the IAPWS water properties model built in so it has all the water material properties (including subcooled/superheated regions). It will be a multiphase model with phase change so a challenge at the best of times but it should be possible. But the devil is in the detail - exactly how are you mixing it and what results are you looking for?
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Sorry for replying so late
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