Error real gas correction
 

Hi guys,

when I try to start my simulation, I receive following error: "Error calculation of rmw in function real_gas_correction: rmw is 0.000000". I activated real_gas_prop_flag and set the maximum reduced pressure to 6.0. If I deactivate this option and set the real gas properties only as a function of temperature, the error will not appear.
I already searched in the CONVERGE manual and the CONVERGE theory manual for a solution, but could not find any information about the parameter real_gas_correction or the meaning of rmw.
It would be very helpful if anyone can tell me the meaning of that parameter and how to modify it.

Thanks in advance.

Best regards

GNKK,

rmw is the reciprocal molecular weight, as an example you can use rmw to calculate the specific gas constant as
Ru= universal gas constant*rmw
For some reason, in your case the rmw is calculated as zero. What type of simulation are you running?

Hey Jerome,

I am simulating the internal flow of a nozzle. I use VOF and RANS models. I use the Redlich-Kwong-Soave equation and species dependent critical conditions. What other information do you need?

Edit: For the initial species inside the nozzle I used only air ( 0.23 O2 & 0.77 N2) and for the inlet boundary I used only C7H16 for the species boundary condition. I changed the species boundary condition now and added a small mass fraction of O2 and N2 (1e-7) and the error does not appear now. Can you explain why? Is it because I use the VOF model and we need some nucleus inside the liquid to develop cavitation?


Best regards

Whatt version of Converge are you using for this study?

Hi,

I am using version 2.2.0.

It seems it could be an error from the code, V2.2 is frozen at this point. Any bug fixes will be added to V2.3. I would recommend using the latest V2.3 to see if your simulation goes through. If you are still having issues please send your input files to support@convergecfd.com. Thank you,