Output Temperature Issues and vaporization capability

[tripatmn]

Hello,

I have been exploring and testing out jax fluids in the past couple days and really appreciate the code, effort and its potential. With that in mind I had a few questions. The context is a vaporization case, essentially heat/mass transfer from one fluid to another

1. In the output, I have used the ideal gas and stiffened gas EOS as defined in the air-water example. When I plot or visualize the temperature, I see that the temperature is in the millions when initial conditions should be around 300K. I am not sure why? could it be because non-dimensionalizing it? I also noticed a StiffendGasCompleted EOS, is that better to use then?

2. To enable vaporization/mass transfer, I turned on the species_diffusion_flux but it didnt make a difference to the results. The website had some promising results in this topic. Is there a capability for this currently or should we expect it in future version or do users have the flexibility to build their own flux models.

Thank You.

[aaronbuhendwa]

Hi,

1. The specific_gas_constant of the air phase is 1.0 in the case setup file. Did you make sure to change that? Otherwise, the temperature computation is incorrect. For this case, we do not need the temperature (no heat flux or any other physics that require temperature computation are active). This is why the case setup file contains a dummy value for the specific gas constant. The non-dimensionalization should be correct.
2. The key species_diffusion_flux in the numerical setup file is currently not being used in the code, this was a mistake from our side. JAX-Fluids currently only supports multi-phase flows without mass transfer across the interface, so vaporization/condensation is not possible as of now. We are planning to add it in the near future. Of course, users can implement their own vaporization and condensation models, but there currently is no specific module/interface for that in the source code. Are you planning to implement this? If so, we are happy to help.

[tripatmn]

Hi,

1. When I try to plot temperature, i get some unreal values and in the stiffened gas eos i saw this line: (image): Since background pressure is so high, it would give high temperatures. I noticed there is a stiffened gas complete eos too, but im getting similar results. In the image attached its only considering back ground pressure and not incorporate the energy reference. That could be the issue

2. I am thinking of implementing this and have sent you an email regarding this. Thanks!