Moldflow Adviser Forum
Welcome to Autodesk’s Moldflow Adviser Forums. Share your knowledge, ask questions, and explore popular Moldflow Adviser topics.
cancel
Showing results for 
Show  only  | Search instead for 
Did you mean: 

Cool analysis has not converged

19 REPLIES 19
Reply
Message 1 of 20
dinesh27mec
1053 Views, 19 Replies

Cool analysis has not converged

Hi,

 

When i run cool analysis for my part, my analysis got failed stating that cool analysis has not converged . I have used 3D mesh for my part. My analysis completed for  another iteration for coolant velocity of 10lit/min for same part. But when i increased the coolant velocity to 189lit/min it didnt failed.

 

What is the reason for this ?

 

Thnaks in advance

Dinesh Kumar D
19 REPLIES 19
Message 2 of 20
dinesh27mec
in reply to: dinesh27mec

sorry when i increased the coolant velocity to 189lit/min. the cool analysis got failed

Dinesh Kumar D
Message 3 of 20
nordhb
in reply to: dinesh27mec

Hi,

going from 10 l/min to 189 l/min is a hughe change.

The high flow rate can cause very high circuit pressure drop and Reynolds number,
maybe unrealistic from what a pump can provide it terms of pressure.
To really understand why a convergence issues, the circuit design needs to be understood.

Basically, the Reynolds number should be greater than 4,000 for lines actively involved in cooling the part
to ensure there is turbulent flow within the circuits and hence efficient cooling.
The ideal Reynolds number to achieve is 10,000.
Higher will increase pumping expenses, cost more energy, and a small marginal improvement in heat transfer.

See:
ASMA Help >  User's Guide > Modeling > Cooling system > Cooling considerations
ASMA Help >  User's Guide > Modeling > Cooling system > Cooling considerations > Heat transfer due to coolant flow
ASMA Help >  User's Guide > Modeling > Cooling system > Cooling considerations > Effective heat extraction

For further investigation please contact Autodesk Technical Support at subscription center:
http://subscription.autodesk.com/
And attach your study file and original cad geometry for further investigation.

 

Regards,

Berndt



Berndt Nordh
Message 4 of 20
dinesh27mec
in reply to: nordhb

But for the same flow rate, the analysis was solved when i used dual domain mesh.
Dinesh Kumar D
Message 5 of 20
nordhb
in reply to: dinesh27mec

Hi,
on a test study using 10 l/min then changed to 189 l/min (and T'inlet=25C) on cooling circuits the analysis converged.
Flow rate : Reynolds number : Pressure drop
10 l/min    : 29522                   : 32kPa (0.32bar)
189 l/min  : 557970                 : 10780kPa (107.80bar) [unrealistic high]
 
What you see is study related.
Why it does not converge is difficult to say without investigating/troubleshooting the study.

For further investigation please contact Autodesk Technical Support at subscription center:
http://subscription.autodesk.com/
And attach your study file and original cad geometry for further investigation.

Regards,
Berndt



Berndt Nordh
Message 6 of 20
dinesh27mec
in reply to: nordhb

Sorry even for DD mesh its not solving . My coolant temperature inlet was 99C. My part size was 3feet
Dinesh Kumar D
Message 7 of 20
dinesh27mec
in reply to: dinesh27mec

I think the water evaporates at this high velocity and temperature. So this might be the reason it cant solve

Dinesh Kumar D
Message 8 of 20
nordhb
in reply to: dinesh27mec

Hi,

I tested on a part 155 mm in length, T'inlet 99C, channel diameter 8 mm.

Material: Generic PP, and Dual Domain mesh, and it converges.

Which material do you use?

Mold and melt temperatures?

Set or automatic cooling time?

 

 

Regards,

Berndt

 

 



Berndt Nordh
Message 9 of 20
dinesh27mec
in reply to: nordhb

35% glass filled Nylon 6,6 . Melt temperature is 340.4 and mold temp is 99. set cooling time 100sec. cooling channel dia 10mm.
Dinesh Kumar D
Message 10 of 20
dinesh27mec
in reply to: dinesh27mec

sorry melt temp is 304.44C

Dinesh Kumar D
Message 11 of 20
dinesh27mec
in reply to: dinesh27mec

Analysis is proceeding after i converted the coolant temperature from 99 C to 25C
Dinesh Kumar D
Message 12 of 20
nordhb
in reply to: dinesh27mec

Hi,

the rule of thumb is to have a cooling inlet temperature 10-20C below wished mold surface temperature as inlet starting point.

 

So if your mold temperature aim is 99C, try to start at 79-89C of inlet temperature.

 

Regards,

Berndt



Berndt Nordh
Message 13 of 20
dinesh27mec
in reply to: nordhb

Hi
Ya its rite, i wil carry out analysis within tat range
Dinesh Kumar D
Message 14 of 20
dinesh27mec
in reply to: dinesh27mec

Hi

 

I tried with coolant inlet temp. at 75 C and at 85C, even for that cool analysis didnt converge

Dinesh Kumar D
Message 15 of 20
nordhb
in reply to: dinesh27mec

Hi,

thank you for the update.

 

Why it does not converge is difficult to say without see how it is modeled and for further investigating/troubleshooting of the study.

For further investigation please contact Autodesk Technical Support at subscription center:
http://subscription.autodesk.com/
And attach your study file and original cad geometry for further investigation.

 

Thank you.


Regards,
Berndt



Berndt Nordh
Message 16 of 20
mayur_dhumal
in reply to: nordhb

Hi Nordh/Dinesh,

I guess increasing the 'Maximum number of Mold Temperature Iteration' value to 100 or more will help here.

Also change the 'mold Temperature Convergence tolerance' value to less tolerance as 0.2 or 0.5 may help.

Just need to navigate to:
Process settings>Fill+Pack settings page>Advanced Options>Solver Parameters>Edit>Cool (FEM) Analysis> Cool (FEM) solver parameters.

I hope this will solve the issue.

Please let me know.

Thanks,
Mayur
Message 17 of 20
nordhb
in reply to: mayur_dhumal

Hi Mayur,
thank you for the suggestion.

It might well solve such an issue similar to this.
Just some comments:
The suggested option is available in Moldflow Synergy/Insight.

The option to change solver setting is not available in Moldflow Adviser though.
Further, Moldflow Adviser use Cool, and does currently not support Cool FEM

Hope this clarifies.
Regards,
Berndt



Berndt Nordh
Message 18 of 20
mayur_dhumal
in reply to: nordhb

Hi Nordh,

Yes i hopped in to wrong project, literally lost that it is Advisor, sorry for that.

In Advisor, Going to 'Process Settings>Accuracy Tab> Analysis Model Processing Resolution' & move to 'Level 3'.

Will it help?

Regards,
Mayur
Message 19 of 20
dinesh27mec
in reply to: mayur_dhumal

Hi Mayur,

 

I did enable  "High analysis resolution"  before my analysis

 

Regards

Dinesh Kumar

Dinesh Kumar D
Message 20 of 20
nordhb
in reply to: dinesh27mec

Hi,

the High Analysis Resolution (in release 2014 and previous),
and Analysis Model Processing Resolution and Levels 0 - 3 (release 2015).
This is basically for mesh refinement, when having a lot of small features.
It does not affect the solver settings as such.
Refining the mesh in this case would probably not solve the issue, as it seems to be process settings and model related to this study.

 

Regards,

Berndt

 



Berndt Nordh

Can't find what you're looking for? Ask the community or share your knowledge.

Post to forums  

Autodesk Design & Make Report