Convergence problems in multiphase flow!

Mikael

Hello,

I´m doing simulations for a helically coiled tube containing a liquid phase along with granules in the Euler- Euler multiphase solver. The problem is that I can't get it to converge. I started out by solving the flow without the volume fraction and got the residuals down to 10e-4 and then they flatened out. After that I added the volume fraction and got the residuals to decrease some without occilations. But after a while residuals starts to occillate very much. I have tried to lower the under relaxation but it didn't help. Somebody who knows what could be the problem?

Another thing is: is it necessary to use mass flow inlet, can't one use velocity inlet instead (the fluent manual says one should use mass-flow-inlet)?

//Mikael