MP-PIC particle volume fraction

Hi all
I am using MP-PIC to solve particle-gas two-phase flow, and I specfied e.g. 10 solids (solid 1, solid 2, …solid 10) to consider particle sizes (polydisperse system) in the problem. There is no chemical reaction in my case. After running, I use postmfix to get the data/results. But I cannot get particle/solid volume fraction for individual solids phases. Could you please help me to solve this?

I have a similar problem like yours. I didn’t find a time to try this solution. Maybe you can read that topic and try Charles’s idea.

Postmfix is not under development anymore. It was used only for TFM. Individual solids fractions are not saved in vtk or monitor files.

1 Like

Thank you very much, Ahmet and Charles. I will try this later. Meanwhile, I am also trying to find alternatives.

Thank you very much, Jeff. Is there any way to save them and extract them?

This is not straightforward. Individual pic phase solids fraction are not computed in PIC, so this will require writing new code. It is not impossible, it depends on your familiarity with the code and ability to write Fortran code.

Thank you, I checked the source code, in several subroutnies e.g. “SUBROUTINE CALC_EPG_DES”, EP_S(IJK,M) is the volume fraction of solids phase M. But it doesn’t work when I try to print the values of EP_S(IJK,M). The other issue is solids phase temperature T_s(IJK,M), is it explicitly obtained, for example, via postmfix?

Usually the IJK in variables of functions such as EP_S(IJK,M) or T_s(IJK,MK) store data at the cell level (IJK is the cell index) and were originally used for TFM model. The subroutine CALC_EPG_DES is used in DEM, not PIC. We do not compute EP_S(IJK,M) in PIC so the data is not accessible (we store the sum of ROP_S, the bulk density in ROP_S(IJK,1) in interpolate_pic.f90). Note that EP_S(IJK,M) is not an array, it is a function that take the ratio ROP_S(IJK,M)/RO_S(IJK,M) so to get EP_S, you need to store ROP_S(IJK,M) and RO_S(IJK,M). I think the same logic used in interpolate_pic.f90 could be used to compute all ROP_S and all RO_S.

Same thing for T_s(IJK,M), this is not a PIC variable so it is not available.

1 Like

Thank you so much, Jeff. I will look into it. Thank you again.

BTW, then how to obtain data if postmfix is not the right way? Thank you.

My suggestion would be to save the data into the vtk files or in the monitors depending on the data you need (data at every cell, average over a region etc). Again, this will require customizing the code.

Thank you very much.