[FrankS]

Hi All,
I am using the immersed solid method to simulate a miniature roots pump I designed. I initially had some difficulty but all is going well with the simulation now and I have got some very informative results.

I can get the torque calculation for the pump lobes in CFD-Post but I can't figure out how to set up a solver monitor for the torque. I would really like to know the torque vs. lobe angle.

The lobes (immersed solids) don't show up at all in the solver monitor controls and I have been unable to get a CFX-Pre expression to recognize the lobes.

Any help would be appreciated.

Thanks
Frank

[FrankS]

I think I may have figured out why I can't get the torque the torque function to work. I have been reading the CFX manual and it says that the torque() function only works on a 2D surface. I was trying to apply it to the immersed solid domain. I will name the walls on the immersed solid and see if I can apply the torque function to that. I will try:

"torque_z()@Immersed Solid Walls" instead of "torque_z()@Immersed Solid Domain" as I was trying to do.

I am new to CFX so forgive me if this is a newb type question.

[ghorrocks]

You are correct - the torque_x/y/z functions by default work on boundary surfaces and immersed solids are source terms on volume regions so have no boundary surfaces. The documentation describes the variables to use for rigid bodies and immersed solids.

[FrankS]

I got it working! I just named the walls on one of the lobes and applied the torque function. So easy!

This immersed solid method is a god-send!

[acardonag]

Hi.


Im trying to simulate a mixer (agitator) using the immersed solid method. Im interested in calculating the torque needed to accomplish a 11 rad/s rotation on my shaft/impellers system, which actually are just a shaft with three blades fixed to it.


Im trying to accomplish this task using the torque function but im not getting realistic results. So I need to ask, which location should I pick for my torque function since it only works with 2D targets and I need to find mostly the shaft torque which is a 3D geometry?


I know this is an old thread and also that my english is not so good but Im out of options. Thx for any advice you can give me.

[acardonag]

Hi, I couldnt understand which faces did you pick for the torque function.

Im working on a shaft+three blades system and I need to find the required torque to achieve an 11 rad/s rotation.

I've been using the torque function picking different faces from my blades but I'm still getting no realistic results.

Any advice?