Miscible mixing
Miscible mixing in OpenFOAM: blending, dilution and stratification
Model two fluids that dissolve into one another rather than holding an interface — blending in a tank, dilution in a pipe, saline or thermal stratification.
What it is
There is no interface to track because the fluids mix. The answer is a concentration field and how fast it becomes uniform, driven far more by turbulent transport than by molecular diffusion at any engineering scale.
What the application sets up
- Properties for both liquids and the diffusivity between them
- Initial and inlet concentration fields
- A turbulence model, since turbulent mixing dominates the result
- Probes and volume statistics, because blending is judged by uniformity over time
- A run long enough to reach the mixing criterion being used
Typical uses
- Blending time in stirred and static mixers
- Dilution and dispersion of a discharge
- Saline and thermal stratification in tanks
- Chemical dosing and residence time
Industries
Sectors where this analysis is routinely asked for.
- Chemical & pharmaceutical
- Water treatment
- Food & beverage
- Petrochemical
What comes out
- Concentration fields over time
- Blend time to uniformity
- Dead zones and short circuits
- Dosing effectiveness
OpenFOAM solvers
twoLiquidMixingFoam
Selected and configured for you from the analysis type. You can still see every dictionary the application writes.
In every tier
This analysis type is in the free build. The free tier limits mesh size to 250,000 cells and solving to one core — not which physics you may use.
On accuracy, plainly.
Every analysis type is exercised end to end on every pass — its case is generated, meshed and run — which establishes that the setup is right, not that the answer matches your geometry. No CFD result is evidence until it is checked against something you trust: a measurement, a hand calculation, or a mesh-refinement study the application will run for you. Treat these results with the judgement you would apply to any CFD you set up yourself.