when fuel is sprayed in engine, jet primary and secondary breakup happen and tiny droplets are formed. The performance of fuel spray in engine depends on the size of these droplets.
The major two phase flow regime in the micro tubes is the Slug flow regime. In this case there is one or few bubbles inside the channel. Hence, it is usually using surface tracking techniques for simulation of two-phase flow in micro tubes.
In this post, i presented my simulation of free surface over cylindrical spillway using OpenFOAM solver (interFoam).
following steps are conducted for preparing case: