Setting Orbital Rotation on a SCROLL COMPRESSOR

Pedro ROS

Hi, I am setting up the simulation of a scroll compressor alike to the one in this picture:

http://www.affordair.com.au/images/whatisaircon/scroll%20compressor.JPG

I had already defined all the geometry and the important meshing into Gambit. Thinking in processing it by smooth and remesh, I made a continuous mesh by permitting a tiny gap in between the two spirals.

Since the movement of the upper part is orbital, there is a crank rotating on the frame-base spiral part, and the upper spiral is actuated by the crank. FIRST QUESTION: Is it possible to define the crank (as a solid continuous type defined as a BC Wall for instance) making it move the UpperSpiral?

SECOND QUESTION: can this be done by an UDF? Where can I find the clues to build the right one up?

Since this movement is decomposed into two angular rotations, by using the reference system on the BaseSpiral Omega_Crank = - Omega_UpperSpiral. I thought about the possibility of erasing the crank and using it as reference system, by giving the relative rotational speeds (same Omega on different axis) to every Spiral part. THIRD QUESTION: has anybody ever done something like this? Is it possible to use a multiple reference frame model? Any recommendation?

Any clues are really welcome.

Regards, Pedro