Impeller simulation

[Anonymous]

Hi all, 

I am new to this software and I'm trying to run a simulation on an impeller using a rotating region. When I try and assign a rotating region to either the Impeller or fluid volume a warning appears saying 'no neighbouring fluid found'. Any advice?

Thankyou kindly

[Jon.Wilde]

Hi,

Assign the fluid first and the rotating region second so that it is within a fluid.

Also, please check out the hangout session we ran on this topic here, it should help you to run this well.

Thanks!

Jon

[Anonymous]

Hi John,

Thanks for the quick reply. I've attatched a screen shot of the impeller in Inventor. On the bottom image I closed the impeller off so as to create an inner fluid volume for computation - as I couldn't use the geometry tool to close of the impeller outlet to assign boundary conditions - is this alright? I only have two regions when transferrd into simulation CFD: the inner fluid region and the solid impeller. Do you mean assign the solid as the rotating region?

Thanks again

Anthony

[Jon.Wilde]

Hi Anthony,

Did you read the guide and see the best practices document that it linked to?

[Anonymous]

Hi John,

I have just read the best practices article and found it very helpfull, thankyou. Just a few questions: How does the rotating region have to be created on autodesk inventor? Is it a solid body? I'm looking to analyse the jet wake profile within the impeller blade channels, is this realistic/achievable? 

Thanks again

Anthony

[Jon.Wilde]

Hi,

Yes this is just a solid body in CAD and does need to be drawn there.

Sure, this is exactly what you should be able to see 🙂

Just be sure that you mesh it well.

Thanks!

Jon

[Anonymous]

Hi John,

Excellent stuff 🙂 You treat it as a seperate solid body I take it? Does it have to be round or can it follow the outer profile of the impeller?

Thanks for your continued support

Anthony

[Jon.Wilde]

Hi,

It would need to be symmetrical but can follow some of the impeller dimensions - perhaps share a cross-section of your model with the RR in place?

I am pretty sure all of this is in the guide I shared too.

Thanks,

Jon

[Anonymous]

Hi,

The clear cover is the rotating region, it touches the impeller hub at the back but has a 5mm clearance elswhere - for reference the impeller has a diameter of 200mm. Is this ok?

The rest of the set-up is the same as the pump tutorial (inlet 5x dia, outlet 10x dia, volute) although the flow is going to be comressible. Would you set up the inlet and outlet as P = 0 in this instance, or could you apply a flow-rate at inlet and keep the outlet as zero pressure? Sorry for the barrage of questions, i appreciate your advice 🙂

Anthony

[Anonymous]

A different perstpective

[Jon.Wilde]

So you would aim for something like this - please do refer to the guide for the distance from the outlet to the edge of the RR. It really depends on hte shape of the volute and how far the impeller is from the walls all around.

(forgive my sketching skills, I'm better with a paintbrush 🙂 )

[Anonymous]

Is that profile for the rotating region or the distance it should be from the surrounding walls? My rotating region is the clear body over the impeller but will change to the one you outlined if this is better for computation. The guides are excellent but dont think they mention whether you can assign any profile shape other than a cylinder as an RR. 

Cheers

Anthony

[Jon.Wilde · Accepted solution]

I don't know where the walls are so this was a guestimate. This is in the ppt within the bottom of that guide - do check it out 🙂

You can assign a different shape for sure.

[Anonymous]

Ok thats great, thanks for your time/help John, much appreciated 

[oafak]

You have responded to this problem in several places and I still cannot follow. The rotating region disappears in CFD when loaded from Fusion 360. I have followed the example but just getting stuck here. Is there any documentation as to how to create a rotating region in CFD. I started a pump drawing from scract but do not know how to assign that property to a region. The example in Tutorial 14 is not working properly; I have tried it several times and receive the same errors.