Fluids

porosity in mixture

• Vinay Neil Panda
Subscriber

I have created a mixture consisting of 2 phases - phase 1 and phase 2. Phase 1 has solids, phase 2 has air - both are within a room. The UDF defined for the simulation provides for mass transfer between the two phases. I have defined porosity for the solids in phase 1, and have toggled off porosity for air in phase 2.

The cell conditions for solids, in the mixture, should have porosity, while the air in the mixture should have no porosity. Yet, when I try to calculate the solution, the solver throws a "floating point exception".

I tried to correct this in the following ways:

1. removing the UDF, and
2. changing the porosity of air in the mixture

What I got from the corrections:

1. On replacing the UDF with a constant term, the calculation works out
2. On making the porosity of air in the mixture equal to the porosity of solids in the mixture, the calculation works out.

But, I need the calculation to work with the UDF, for 0 porosity of air in the mixture. Please let me know what I should do

• DrAmine
Ansys Employee

I do not understand the case: Can you add some more information about the application? What do you mean with porosity for solids? Do you have separate cell zones? Different Domains?

• Vinay Neil Panda
Subscriber

The application is - Moisture transfer from one phase (consisting of solids, air and water vapour) to another phase (consisting of air and water vapour).
To this end, there must be porosity in the 1st phase, and there is no need for porosity in the 2nd phase.

The solids in phase 1 are basically separate boxes, so each box is considered a cell zone containing phase 1. Phase 2 (air and water vapour) surrounds these boxes. The two domains are phase 1 and phase 2, between which there is mass transfer.

• DrAmine
Ansys Employee

So the solids are modeled as solid part of the porous media? Still not clear..