This scene file has been setup with helpful annotation notes applied to some of the objects. Within the scene you'll see how the nxFluid solver and nxFluid tags work to drive the two different particles states. These behavioural states can be triggered using fields. This scene has a different field modifier that creates a more leaking melt behaviour.

Render created using Redshift but any render engine could be used.

To speed up calculations you can create less particles in the model by changing the particle radius size under Emissions tab in the Emitter. currently it is set to 1cm but if you changed this to 2 or 3 it will calculate faster. The only draw back is that there is less particles so the mesh will be less detailed.