SimScale CAE Forum

Axial Pump


#41

That is correct, but software seems to use left hand rule, axis your thumb is pointing to (direction) is > than origin. Normally it also should be enough to specify any set of points in a space along rotation axis.

If you rotates along Z axis (X,Y being 0), 0, 1 points toward Z POZ. 100, 101 or -101, -100 on the Z axis does the same.

However I was completely misled by my cylinders rotating in both directions in any case they were shifted in X and / or Y axes. As Ruben said that ‘they are working on it’ I stopped to experiment with that setting awaiting the fix. As precaution I decided to define a rotating axis of MRF zone as ‘piercing’ that zone, even if it was centered on 0 of an axis. Sounds like superstition I dislike, but I need this fix first.

In meantime I possibly discovered another problem in CFD, but will tell you in a different thread.

Thanks,

Andrzej


#42

Hey guys!

Not up-to-date what you have discussed so far but very flourishing conversation I have to say :slight_smile: Just so that you know. It is the right-hand rule that is applied for MRF and not left-hand as assumed. Can someone tell why you think it seems to be left-hand? Could be that the geometry is flipped and wrongly inclined/oriented.

Best,

Jousef


#43

Please go to: https://www.simscale.com/workbench/?pid=5613410603720597392&rru=c0c285e7-74ee-4ec9-b897-7879a16f98b0&ci=a94b1b7c-daa3-4cd4-b6fc-1dcc74d79d28&ct=SOLUTION_FIELD&mt=SIMULATION_RESULT

If you are lost, it is CylRotMastSTL > RanTransparent Walls.

Rotating axis is Z. Axis is defined at origin -0.26, axis pointing to 2.26. Rotation speed is +rad/s from CSV table. So, perhaps it is an exception?

Cheers,

Andrzej


#44

@jousefm

I am not sure this example backs up your above statement.

In my sample project I created for this pump, here we have Run3 MRF parameters (note the +ve rad/sec value) and the resulting head was -ve and the magnitude was near experimental results:

In Run 1 here are the MRF parameters (note the -ve rad/sec value) and the resulting head was +ve and about 10x the actual magnitude of the experimental results:

I don’t think I need to show streamlines that the water is flowing properly in Run 3 (the good run).

Note: The rotor is located to spin about the x-axis, inlet face is on the right side.


#45

@jousefm: I suggest the problem of MRF rotating zone in BOTH directions is fixed first. Bottom line is that you are 50% right. Example I provided, is just an exception as 100% of MRF zone rotates in wrong direction.