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-   -   Mixing tank impeller (https://www.cfd-online.com/Forums/fluent/133630-mixing-tank-impeller.html)

Onicon April 17, 2014 16:29

Mixing tank impeller
 
Hello. I am trying to model a mixing tank with a single impeller. I am using a rotating reference frame, where I've created a cylindrical rotating fluid around the impeller and defined its rotation.

The problem I'm having is that, when run as steady state, the non-rotating fluid hardly seems affected by the rotating fluid (which in turn doesn't seem affected by the impeller). I've tried different impeller sizes/shapes/blades, but it hardly seems to have an affect on the flow, it mostly just looks like a rotating cylinder of fluid.

In a 1000L mixing tank, I'm seeing very slow velocities away from the rotating fluid zone, 0.01 - 0.10 ft/s, with the rotating fluid moving at 200rpm. I have run the mixing tank in person, and clearly there is more activity irl.

Any thoughts on what I'm missing?

Natali March 24, 2015 02:43

Hi, Onicon. I have the same problem as you. Have you decided this problem? I have two parts. One part is a rotating cylinder with emptiness inside in the form of mixer. And the second part is square tank, that surrounds rotating frame.


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