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Modeling a Planetary Mixer

Hi,

I am trying to model a transient analysis of a planetary mixer but I do not know how to properly introduce the motion in the model. It consists of a shaft rotating around its axis while also rotating around the central axis. I have tried by defining two fluid regions, one close to the shafts with the a mesh motion (the rotation of the shaft around its own axis) and the rest of the fluid with the rotation around the central axis. As I expected, this resulted in a distorted mesh and AcuSolve stops the simulation. If anyone could point me in the right direction about really appreciate it!

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ydigit

Do you have an image of the setup?

I believe a SPH (meshless) based method, NanoFluidX would be more appropriate for such a simulation.

There are also planetary gear systems done with it. For details check: http://www.altairhyperworks.com/product/nanofluidx

Altair Forum User

I am using the sliding mesh method. I have defined a UDF with a rotation matrix combining both rotations for the sphere and the fluid contained within the red interface. I have also applied a rotation to the rest of the fluid. AcuSolve runs the simulations but when I look at the results in AcuFieldView I can see that everything moves the way it should, including the interfaces except for the sphere which seems to stay in the initial position. There is also fluid coming into the void that should be occupied by the sphere. I believe that this comes through some error in the UDF but I am not sure as I have never used one before. I have also tried writing the UDF with only the rotation around the main axis but the same thing happens.

<?xml version="1.0" encoding="UTF-8"?>

Altair Forum User

I solved the problem, I had one wrong minus sign in the UDF that changed one of the components of the rotation matrix. Thanks anyway!