[dfownz]

Hello all!

I work in the extrusion industry as a design engineer and I am looking use the Giesekus model to simulate molten plastic flowing through passages. I'll be using OpenFOAM.

My current approach is to simulate using a viscosity model (cross or power law) and I am sometimes right but sometimes very wrong with the predicted pressure of the system. I'm hoping by using a viscoelastic model I'll be closer to reality. I've noticed my predictions are much closer when G'' is the dominating term below 100 1/s. When G' is the dominating term shear rates less than 100 1/s I am very wrong.

I have a rotational parallel plate rheometer and am specifically interested in doing this for HDPE.

My issue is I do not clearly understand what kind of test is required to fit the Giesekus parameters. I'm hoping someone can offer assistance for what tests are required. I can then run the tests and provide them to repay my debt!

Finally, I have RheoChart to help fit the parameters.