bonnie77
Geotechnical
- Mar 19, 2009
- 1
Hi everyone:
Is anyone familiar with phase change calculations in ANSYS? I would really appreciate some conceptual help.
I have results from separate thermodynamic calculations of (1) solidification and (2) heating up/melting. I now want to incorporate the thermo results in ANSYS (command line) to find out how the solidifying substance affects its surroundings (i.e., how the surrounding container heats up and melts; length and time scales). I am using example 3.93/3.94 (Example of a transient thermal analysis/Commands for building and solving the model) as a guide.
Two questions:
1) In the ANSYS example, only the solidifying stuff changes phase. In my calculations, the solidifying stuff AND the container (which may melt) change phase. Can I define two MPDATA,ENTH tables in a single phase change calculation, one for the container and one for the solidifying stuff?
2) Here's the conceptual issue: My separate thermo calculations yield NEGATIVE enthalpies of formation. Is this OK? Physically, I know it's OK, but is it OK in ANSYS to enter negative enthalpy values? Can I simply plug these negative values for (1) the container and (2) the solidifying stuff into the MPDATA tables? I can't simply remove the signs because then I will get enthalpy versus temperature curves that are negative and ANSYS doesn't allow this. These are enthalpies of formation, not flow values.
Thanks a lot for any help.
Is anyone familiar with phase change calculations in ANSYS? I would really appreciate some conceptual help.
I have results from separate thermodynamic calculations of (1) solidification and (2) heating up/melting. I now want to incorporate the thermo results in ANSYS (command line) to find out how the solidifying substance affects its surroundings (i.e., how the surrounding container heats up and melts; length and time scales). I am using example 3.93/3.94 (Example of a transient thermal analysis/Commands for building and solving the model) as a guide.
Two questions:
1) In the ANSYS example, only the solidifying stuff changes phase. In my calculations, the solidifying stuff AND the container (which may melt) change phase. Can I define two MPDATA,ENTH tables in a single phase change calculation, one for the container and one for the solidifying stuff?
2) Here's the conceptual issue: My separate thermo calculations yield NEGATIVE enthalpies of formation. Is this OK? Physically, I know it's OK, but is it OK in ANSYS to enter negative enthalpy values? Can I simply plug these negative values for (1) the container and (2) the solidifying stuff into the MPDATA tables? I can't simply remove the signs because then I will get enthalpy versus temperature curves that are negative and ANSYS doesn't allow this. These are enthalpies of formation, not flow values.
Thanks a lot for any help.