Alpha higher than 1 and mules implicit.
 

Greetings.
I'm trying to simulate a three dimensional biphasic flow in microchannels. I'm using interfoam as solver, and i have the problem that the maximum value of volume fraction is higher than 1 (about 1.3). I don't know how to resolve this...Is there a way to set mules to implicit? Do i need only to change explicitSolve to implicitSolve in alphaEqn.H? I've also limited the maximum Courant number to 0.2 without significative results.
Thank you.