[cqlwj123]

I am model the welding process. The steel (Q235) undergoes melting and solidification under the heating arc and, at the same time, molten steel drop into the molten pool. I want to know the shape of welding bead and it is regarding two phase (air and liquid), free surface, and heating problem.

First, I modeled the steel as a liquid. There are steel and air in the domain. After adding a volumetric heating source onto the steel, there can get a right temperature field.

Then, I add General Momentum Source as following to force the steel under temperature 1753K to a velocity of 0. I have added a Continue source of Q235 to model molten steel drop into the molten pool. It is named Rongdi. But this time, the temperature is not right.
Sx=C*step(1753-Q235.T/1[K])(Q235.velocity u-0)
Sy=C*step(1753-Q235.T/1[K])(Q235.velocity v-0)
Sz=C*step(1753-Q235.T/1[K])(Q235.velocity w-0)
C=-10^7

I have enclosed the .def documents, and please give some suggestion for me. How to add a general momentum source and continum source in my case? Does my boundary wrong?

.def file download
In my domain, the steel is 3 mm in thickness (from z=-0.006mm to z=-0.003mm), others is air.