[Sijnhaven]

Dear all,

I would like to know your opinion about a mixing time calculation approach:

It concerns a multiphase liquid-gas simulation. The liquid is patched in the reactor and the gas enters through nozzles. No gas is present in the initial solution. The gas is used for mixing the liquid. I would like to compare different inlet gas flowrates in their efficiency of mixing the primary, liquid phase.

The models that I am using: Energy, Multiphase VOF and k-e turbulence.

These are the steps in determining the mixing time:

- Define a new tracer-material with same properties as the liquid.
- Patch the tracer in one cell on the liquid domain (volume fraction = 1 here).
- Define 3 vertical planes in the domain (these are the 'probes').
- Report definitions -> New -> Area-Weighted-Average of volume fraction of the tracer phase (do this for the three planes).
- Report plot of the three area-wheighted averages.
- Start calculation: mixing is achieved when the area-weighted-averages of the volume fractions of the tracer phase are the same on the three planes.

* Please give your opinion: is this a good approach?
* Often species transport is used in mixing time calculations. But in this case the tracer is treated differently than the liquid? Can it be done without species transport like in this approach? Why not?

Thank you