Centrifugal Pump Cosmos Floworks Problem 3

[019342806]

I am very new to Floworks and have created a centrifugal pump that consists of an impeller and a scroll casing. I need to assign an environmental pressure at inlet and outlet and let Floworks tell me the flow rates.
I am trying to simulate the fluid flow in the pump but I am having a few problems. I cannot select the impeller as a rotating region, even with it disabled. It was suggested that I should create a hidden part that covers the whole impeller, this worked and I assigned this as the rotating region, the airflow around the impeller now looked good but the results around the edge of the casing don't look right, there seems to be a separation of the two regions.
I have watched a Solidworks tutorial and on this you can see a hidden 'cavity part' and so I think I am on the right lines.
Please could anyone tell me if I’m doing this correctly?
Regards
Steve

 

[gerdjan]

I think that's what I need to do too, having the solver abnormally terminated a lot of times because of too much memory usage, while having the initialmesh just at level 3.

I am not able to set two boundary conditions at one outlet.
it gives the next error:
Face<1>@Assem1-1 already belongs to Static Pressure 1.
So i can set only 1 condition to the outlet lid.

My last try to solve my case didn't work either. I set a staticpressure at inlet and outlet, and a goal for the flowrate. I didn't use any goal for covergencecontrol. and let the solver run for more then 2 days. at 4389 iterations it crashed again, and i still didn't had a steady flow.

How many iterations are roughly requierd to solve a centrifugalpump? I know it depends on a lot of things, but is it closer to 300 or 30000?

 

[MikeCool]

Probaly closer to 300. I have never seen a good convergence beyone 1000, but you'd have to ask tech support on that one. I suppose it all depends on your mesh, given good constraints and goals.

We have had many sims blow up too, so you are in good company.

What are you trying to do, and why? BTY, in one of your pics above, you have the impeller turning the wrong way.

Keep in mind, this software is only a guideline. It is best for comparing two or more similar systems, and determining which is better. It isn't necessarily the best for determinining what a production model will do in real world conditions within 3% accuracy.

Contact me.

Mike

Mike Cool
Mechanical Engineer
American Stainless Pumps, Inc.
Los Angeles California USA

http://www.aspumps.com

 

[gerdjan]

Hello Mike,

I'm doing a traineeship at a pumpfactory in the Netherlands.
We recently got a licence of Floworks, and I am trying to find out if it can be used within our company. And how much the results of floworks match with real world conditions.

The impeller in the pic above should be turning leftwards. I have set a negative value for angular velocity.

I think the best thing for me to do is studying the meshsettings.

What should I expect about accuracy in compare to real world conditions? is it less then 10% ?

 

[MikeCool]

You can't know your accuracy until you get your results and compare to test data. It often goes both ways, +/-. Each engineer must perform their CFD studies, and compare to test data, then re-test with different mesh settings until you start to get close. That experience will allow you to become more accurate with your future tests.

Mike Cool
Mechanical Engineer
American Stainless Pumps, Inc.
Los Angeles California USA

http://www.aspumps.com

 

[gerdjan]

That's what i'm doing right now. I have the testdata of the pump.
So i will keep trying

thanks a lot for your help

 

[MikeCool]

Best of luck to you. If you get good results, please forward mesh setting details.

Mike.

Mike Cool
Mechanical Engineer
American Stainless Pumps, Inc.
Los Angeles California USA

http://www.aspumps.com

 

[biovitta]

I've a problem with analisy, my simulation is like a pump, centrifugal fan the same ideia, but when I run the floworks show me a different volume flow rate inlet than outlet. I use a impeller rotation with static pressure on inlet and outlet. and on surface goals the volume is different. Any one can help me with the data?
thx