[ata]

Hi KyleL
As I said I am interested in. I had some literature review. Did you have too?
What is your plan?

[KyleL]

Ata,
I guess my plan is to first find out what if any development has been done? Then I would like to review any information available, and maybe find a programmer that would be willing to help develop the needed moldFOAM solver.
I would very much like to see any information you have available.
Thanks,
KyleL

[ata]

Hi Kyle Lampkin
I have some paper a bout this, but now I don't remember their title and authors and I must take a look at my resources. Do you want them? If yes I'll send them for you.
All the best

[vkrastev]

Are there any updates about this matter? I'm really interested in any applications wich involve the use of the OpenFOAM frame in simulating the injection molding process for polymers.

Thank you in advance

[ata]

Hi
I have written a two phase code for polymer processing but now I am PhD student and I can not release it until the end of my PhD but if you want may be I could help you in code preparation or you can wait until the end of my PhD.
Best regards
Good luck

[alberto]

Originally Posted by ata

Hi
I have written a two phase code for polymer processing but now I am PhD student and I can not release it until the end of my PhD but if you want may be I could help you in code preparation or you can wait until the end of my PhD.
Best regards
Good luck

Hint: write a paper on it, with the details of the implementation, the numerical treatment and all the bits. It's a very good way to protect the authorship of your work.

Good luck!

[ata]

Hi Alberto Passalacqua
I am doing that and after publishing my work, I'll release my code.
Best regards

[vkrastev]

Originally Posted by ata

Hi
I have written a two phase code for polymer processing but now I am PhD student and I can not release it until the end of my PhD but if you want may be I could help you in code preparation or you can wait until the end of my PhD.
Best regards
Good luck

First of all thanks for the reply. Secondly, of course I do not ask for your source code if it hasn't been released yet (I'm a PhD student too, soo I can easily understand the importance of protect the autorship of your work). Actually at this stage I only want to understand if such a complex flow has already been approached inside the OpenFOAM frame and how, in general terms, it can be implemented. So, generally speaking, can you tell me how did you approach the problem (I mean: are the two phases isothermal or not? Did you start with modifying some pre-existing multiphase solver, such as the interFoam one? Is the polymer fluid treated as a non-newtonian one?)? Thank you and good luck for your PhD!

[ata]

Hi
My code is isothermal solver for two phase flow. Two phases can be viscoelastic-viscoelastc fluids or viscoelastic-Newtonian fluids. There is about 15 constitutive models available for viscoelastic fluids in my code and geometry is general in it. I used from interFoam and viscoelasticFluidFoam solvers and combined them.
I think it is not very hard to add energy equation to may code.
Thank you very much for your understanding me and my restrictions
Good luck with your PhD too

[alberto]

Originally Posted by ata

Hi Alberto Passalacqua
I am doing that and after publishing my work, I'll release my code.
Best regards

That's great! I suggested that because a lot of work is going on with OpenFOAM, at least judging from this forum, but not as many papers are around ;-)

P.S. Didn't mean to put pressure :-)

[erikappel]

Originally Posted by ata

Hi
My code is isothermal solver for two phase flow. Two phases can be viscoelastic-viscoelastc fluids or viscoelastic-Newtonian fluids. There is about 15 constitutive models available for viscoelastic fluids in my code and geometry is general in it. I used from interFoam and viscoelasticFluidFoam solvers and combined them.
I think it is not very hard to add energy equation to may code.
Thank you very much for your understanding me and my restrictions
Good luck with your PhD too

Hi
I have some students working on developing a code for simulation of injection moulding. They used interFoam and added an energy equation to the solver, part of the problem is discussed in following thread:

http://www.cfd-online.com/Forums/ope...sitymodel.html

The non-isothermal behavoiur is based on the paper:

"A novel design for hot-melt extrusion pelletizers"
Stefan Radel et. al.
Chmical Engineering Science 65 (2010) page 1976-1988

If the company involved in the project accepts, I will ask them to disclose the code and test case. However, there is still an issue about the frozen layer.

[awacs]

Originally Posted by ata

Hi
My code is isothermal solver for two phase flow. Two phases can be viscoelastic-viscoelastc fluids or viscoelastic-Newtonian fluids. There is about 15 constitutive models available for viscoelastic fluids in my code and geometry is general in it. I used from interFoam and viscoelasticFluidFoam solvers and combined them.
I think it is not very hard to add energy equation to may code.
Thank you very much for your understanding me and my restrictions
Good luck with your PhD too

Hi Ata,

Is the melt compressible in your code? Do you take melt solidification into account in your solver? I am interested in injection molding simulation, too. Hope that we can hellp each other.

Best regards

[ata]

Hi Jitao Liu
As now code is incompressible with no melt solidification. I would be very glad if I can help you and have cooperation with you.
Best regards

Ata

[skykzhang]

Hi, Ata
I want to combine the interFoam and viscoelasticFoam to simulate the polymer injection, just like i said in the other post. But in the interFoam solver, there is a "transportmodle" file in it ..., I have no idea to put the viscoelastic informations in it. How can I do? can you give me some advises on that?
If it is convenient, you are appreciated to e-mail me: skykzhang@hotmail.com

[ata]

Hi
I ignored the transportmodle. Write one similar to it for your self.

[skykzhang]

Originally Posted by ata

Hi
I have written a two phase code for polymer processing but now I am PhD student and I can not release it until the end of my PhD but if you want may be I could help you in code preparation or you can wait until the end of my PhD.
Best regards
Good luck

ata, did you get your PhD already? you are appreciated for realseing the solver.

[Pisolino]

Hi all, i'm very interested in this project. There is still someone working on it?

[cramsdead]

up?

it is possible to access to all the work you did guys?

[crixman]

Hi guys,
any updates on the solvers? Would be interested to contribute, maybe adding a scalartransport equation to introduce temperature in the flow.
Let me know,
Christian

[thomasArk47]

Hi guys,

throughout this OpenFOAM forum, I see that many people are interested on the topic of "injection molding" with OpenFOAM.

It seems that some people have build a solver for this topic. Something based on interFoam for interface tracking, adding heat transfer, rheology and so on. Nevertheless, I'm not aware of anybody who has released such a solver

Well, I work on this topic for a long time and, from my point of view, it is a quite complex story to build such a tool. You could find some hints below.


Overview of the problem:

the cornerstone of the problem is not the heat transfer or rheology behavior (not an easy task nevertheless...) but the tracking of the interface by itself. Indeed, the main difficulty (for OpenFOAM) is that we need to deal with a highly viscous phase (the polymer) with something like air (not viscous at all). Mmm, it seems abstract at this point of the story We have something like interFoam no? Where is the problem?


Common simplifications:

in a first step, you can drop all transient and convective terms in the base Navier-Stokes solver --> you are dealing with pure Stokes problem now (it is what all standard softwares like Moldflow do by default). It should be easy now? --> not at all in fact You are just at the cornerstone of the problem: you need to deal with a Stokes system with a highly viscous term and a quasi inviscid one. Ok, another common simplification is to consider that air has a viscosity something like viscosity(polymer)/1000. For example, if your polymer has mu = 1000 Pa.s, then take mu(air) = 1Pa.s. It doesn't change significantly the flow front evolution and it reduces the stifness of the problem.


Still a nightmare:

Previous simplifications are good but far from being enough
The Stokes problem we need to deal with is still too stiff... for OpenFOAM.
The problem is heavily linked with the numerical kernel of OF: cell-centered FV with segregated approach for U/p. Not good at all for Stokes operator with strong jump on viscosity and high viscosity. The underlying reasons are not so clear from strict analytic point of view (search this topic on google scholar / you won't find many things). Ok, two things: 1- first recall at least that it is a quite well-known fact that cell-centered FV are bad for diffusion operators on irregular meshes --> there is "reminescence" of this behavior on eulerian tracking schemes (on perfectly regular meshes!), 2- secondly, try to use the interFoam to simulate the falling (by gravity) of a highly viscous drop (say a drop of radius 1mm with density 1000 and viscosity 1000Pa.s) in ambiant air and see the result. You should understand quickly what happens.


What you could do:

1- Work with a finite element solver for U/p (you can track alpha with FV if you -- still -- like them!).

2- Ok, i'm a bad guy. It could have some solutions also for finite volume framework but it is not "proven" and they are difficult to implement in OpenFOAM:

a- modern finite volume methods like DDFV. Search a paper of Jerome Droniou, "Finite volume schemes for diffusion equations. Introduction to and review of modern methods" --> just an introduction, not focused at all in diphasic Stokes problem / rather some approachs (DDFV but some others) for working with quite irregular meshes / some peoples have succesfully applied them for biphasic Stokes flows with good results. Highly interesting / quite valuable for amening OpenFOAM to a high level of numeric technology / but quite complex to implement properly and quickly. Obviously, if you are able to do such a thing by yourself, you would be a god if you release freely such an extension to the OpenFOAM community! Seriously, it is a quite complex topic and "a job by itself". You need to be a researcher on this topic to achieve it.

b- things should be quite better if you work with the coupled U/p solver of the extend version --> I haven't do it. If you do it, please give me a feedback... and I will give you the implementation the 3rd solution

c- keep the segregated approach, strenghen the viscosity flux (like for classical diffusion), clean up gradient pressure reconstruction used in OF, use a ghost fluid type method with a levelSet, and do a lot () of pimple iteration to enforce U/p coupling. It is the easiest approach. It is "not so long" to implement / it "works"... but not the result (accuracy versus CPU time) is not as good as a standard software based on Finite Element.

Nightmare is not finish... It begins!

If you start some works on this topic, you will quickly face the problem of the wall boundary condition treatment A physical fact: at the melt front position, the polymer "partially slip" along the wall... It is a big / interesting / and complex story to deal accurately and efficiently with this (now you should guess that it is not sufficient to use something like the "partialSlip" BC of OF).
Maybe more on this topic later


.................................................. ...........................

Well, is it yet an easy task to do injection molding with OpenFOAM??? Mmm, maybe it is for this reason that nobody has released a real solver for it...