Rotating Impeller

[Lomea]

Hello,

I would like to study the flow of air in a rotating turbine. The goal is to create an air flow from the bottom by rotating the turbine at 15.000 rad/s.
I am using Floworks 2009 for the first time for this project.

So, before working on the real turbine model I made several tests on a very simple form of the turbine in order to choose the best way to simulate it, since there are different ways to add a rotation on a model.

So far, I could see that there are 6 different ways of modelisation:
Using a Global Rotation, a Rotating Region or Moving Walls with an Internal or an External analysis.

There are many differences among the results, depending of the method used. Which one would you think is the best to simulate our case, considering that the rotating speed is around 15.000 rad/s ?


You can find joined the screens I made for each method, with some explanations about my choices (all the examples following were made with a -20 rad/s rotating speed).


Thank you for replying.

 

[EngAddict]

I think you want rotating region but it has been a while since I looked into this stuff.

 

[321GO]

I have experimented with a similar setup some time ago (a ventilated brake disc).

I agree with the local rotating region. But i do not understand why you modelled it with and without the lid in setup 5 vs. 6. Obviously the rersults differ since the modelling setup is different, right?.

Why not model the way it actualy is (with the correct lid)?

I don't think the global option is suitable. Suppose you constructed a turbine without blades, spinning at 15k rpm. Than the air inside the global region would also be spinning at the same radial velocity, which obviously isn't a representation of the real world.

 

[321GO]

Lomea,

how did it work out? What was your final approach?

 

[Lomea]

Hello,

Thank you for your reply, and sorry I haven't replied earlier. Using another forum and after some tests, I figured out that the best way was a global rotating, with external analysis mode.

The global way remains suitable since I don't have any stationary part in the assembly.