Hi,
I am new to MFiX, please how do I incorporate reaction rate coefficients into my reaction stoichiometries? I can’t see where to input them. More so, in an attempt to test-run without the rate coefficient, I keep getting the below error message. Any idea on what went wrong and how to resolve it? Thanks
“ERROR rxn_com_mod.f:600
Error 1100: One or more phases associated with reaction REACTION_1 has specified constant specific heat (C_PG0/Cps0). This is not permitted for reacting phases”.
Did you ever figure out how to fix this error? Because I am getting the same one now!
Hi Amanda
Reaction rates are specified in user-written FORTRAN files usr_rates.f - check the silane_pyrolosis or absorbtion_column tutorials.
The control for keyword c_pg0 is here:
the error message is telling you that instead of Constant you should set specific heat to “Mixture - use MFiX default calaulation”. There are similar controls for the specific heat in the solids phases.
If you are not sure how MFiX keywords are mapped to GUI controls, click the “Search for MFiX Keywords” icon in the top toolbar.
– Charles
Hi Charles!
I see. My solid’s specific heat does say constant; however, I can’t change it. That variable is greyed out, so I can’t switch it to mixture, and I don’t know how to make it available.
I attached my .mfx and usr_rates.f files below.
Thanks a bunch,
Amanda
model.mfx (16.0 KB)
usr_rates.f.txt (584 Bytes)
If you hover over the “Specific heat” label or the input box you will see a help message that says “Requires energy equations”.
I wonder how you got C_PS0 set to 830 without that control enabled. Did you have energy equations enabled at one point, set that value, then disable energy_eq? Otherwise I’m not sure how you got into this situation. Maybe it’s a bug in the GUI?
– Charles
I never set that value; when I create a new solid, it automatically sets it to 830. I didn’t know you could make the specific heat available by enabling energy equations! Thank you for telling me this because I did fix my issue by enabling energy equations, allowing me to change the specific heat to mixture, and then disabling energy equations again. I don’t know why it automatically goes to 830! But this helped a bunch! Thank you so much!
Amanda
Ok, I’m glad you could work around your problem. This is a bug in the GUI which I will fix for the upcoming 21.2 release. 830 is specified as the default value for C_PS0, but it should only be getting set when energy_eq is enabled. Sorry for the inconvenience.
– Charles
The hover-over help (“tooltips”) often contain information about why controls are disabled. In this case the tooltip appears on the label and the text entry box but not on the dropdown, due to a small bug.
按照您的方法，好像并没有解决问题，我通过GUI里边加入了MgCO3=MgO+CO2这个反应，但是他给我报了相同的错误，难搞，望解答！
Please post in English if you want help from the MFiX staff. Thanks.
