casting processes
 

Good morning SSSS,

I'll try to realize all your instructions over the day. The greates challenge seems to be the new convMeltFoam approach.

Attached you'll find the hole code. I also extended the immiscibleIncompressibleTwoPhaseMixture and incompressibleTwoPhaseMixture in order to store the thermophysical properties. You'll find the new transportModels attached as well.

Thanks,

ole

simple test case for casting processes
 

Here is a simple test case for my solver attempt. It simulates a simple cube which is open to the atmosphere at the top and has an inlet at the bottom.

A good introduction to the ideas, discretisation and solving strategies of interFoam seems to be the following pdf:
http://infofich.unl.edu.ar/upload/3b...7523c8ea52.pdf

casting processes
 

Here is a revised version of my 3 phase attempt. Following the hints of SSSS the main changes are:

• reduced size, 2D domain inkl. symmetryPlane
• rho and cp is equal for liquid and solid
• rho becomes a volScalarField featuring the Boussinesq approach
• added TEqn.relax()

The TEqn still doesn't work. Just cooling the cube results in higher temperatures than initiated and filling the isothermal cube results in floating Point error after raising and dropping T and liquid fraction.

Two ideas are still open:

• Do anybody know an alternative approach to convMeltFoam, which doesn't use the convective term fvc::div( *** , fl )?
• How can terms in the TEqn, which depend on the melt fraction (alpha1 = liquid + solid) be limited, other than just multiplying it with alpha1?

Thanks,

ole

New try with the approach from file:///home/konsole/Downloads/PhD_Thesis_ZSSALDI.pdf

Hello there,

does anybody know a common test case, which consider a phase change due to melting or solidification and the propagation of the PCM (phaseChangeMaterial). I want to benchmark my solver.

The frame is a casting process.

Hi Ole,
I did some validations for some extreme conditions of melting/solidification here: http://people.eng.unimelb.edu.au/ima...ngs/19/142.pdf

Cheers
shakil

Species conservation equation in PimpleFoam
 

Hi there, I am a new former, which is described in attachment is species conservation equation . Now here is my problem, I don't know how to implement the species conservation equation in PimpleFoam accurately, if there were someone give me a guidance or show me how to do that, I will be very appreciate!Attachment 40892

Regarding different versions of "convMeltFoam" solver
 

Hello phase-change foamers,

I downloaded the Anja's modified version of Fabian's "convMeltFoam" solver for OF2.3 (post #119) and also the latest (if I am not wrong) parallel version from Fabian's solver posted by himself (post #139). I tried the first one (let's call it "Anja's modified version" for clarity) and it runs normally but when I tried the other in serial case (let's call it "Fabian's latest parallel code") I get an error in Transport properties. Specifically, it asks for "mu0" and "muk" and from what I've seen they are declared this way in the respective "ReadTransportProperties.H"; when I put some values in the dictionary I receive an error about dimensions. I suppose that "mu" stands for dynamic viscosity with respective units [Pa*s]-->[kg/(m*s)]. On the contrary, "Anja's modified version" just asks for "nu" (kinematic viscosity) and the case runs without any problem (in OF 2.3.0). What could be the problem?

Thank you in advance!

Hi manalis

It's a long time ago since I posted this solver here. However, I remember that the viscosity was implemented temperature dependant.

So mu0 has the same units as dynamic viscosity [kg/(m*s)] and muk has reciprocal temperature units [1/K].

Cheers

Fabian

Hi Fabian and thanks for the immediate response!

After your suggestion and some minor changes in the "system" folder dictionaries I made it work! Up to now I have been using Fluent for my melting/solidification cases and very recently (actually last week) I decided to try the approach in OpenFOAM. So I am really new to this. Could you explain a little bit the expression for "mu" that you posted? What is the meaning of "scalar(0)", "scalar(1)" and "muk" in your code regarding the way that viscosity is changing with temperature? Have you tried to implement different properties for the 2 different phases with a high viscosity value for the solid phase?

Best regards

convMeltFoam
 

Any thoughts/suggestions regarding viscosity equation? Apart from that, I would be very interested to know if someone has dealt with contact melting (e.g. melting inside a closed capsule) with this specific solver.

Best regards

solidificationMeltingSource
 

Hi folks. During a small solver research within OpenFOAM 2.4.x I found a new fvOption for solidification and melting:
Basically it uses the same approach as most solvers in this thread - the enthalpy porosity method by Voller and Prakash.
So just in case somebody is new to this thread or it's topic. This is one way to go besides the proposed solvers in this enlightening thread.

Cheers

Fabian

Ole,
interTempFoam is created for what version of OF? The case files seem to imply version 2.3.0, but when I compile it, I get errors stating that the class 'immiscibleIncompressibleTwoPhaseMixture' (in alphaCourantNo.H) lacks a member named 'nearInterface', while UEqn.H and pEqn.H lack members named surfaceTensionForce. Do these members exist in some other version of OF's immiscibleIncompressibleTwoPhaseMixture?

Setting up melting problem with interTempFoam for 3 phases (ice, water, and air)
 

Hi Ole,
I successfully compiled your solver based on Z. Saldi's thesis (see post #205). I'm trying to setup a problem with a block of ice immersed in heated air. I'm trying to use the 'setFieldsDict' to set the alpha1=0 in the air region and alpha1=1 in the water region.

Within the water region, I want to make part of it solid (ice) and the other part fluid (water). Should I set alphas=0 for the ice and alphas=1 for the liquid water region (only in the water region)? Or should I set alphas=0 for the ice region and alphas=1 everywhere else?

Please let me know how best to setup this problem with your solver.
Thanks,
Paul

Hi Fabian,

Could you post your modified convMeltFoam solver that incorporates the third phase (air), as suggested by your thesis?

convMeltFoam OpenFoam-3.0.0
 

Dear phase-change Foamers,

did anyone convert the convMeltFoam solver from the post http://www.cfd-online.com/Forums/ope...tml#post484860 above to OpenFoam-3.0.0??

Cheers,
Alex

I have uploaded a functional demo case of gallium melting here on the forum which might be helpful for people starting on phase change modeling using the fvOption "solidificationMeltingSource"

http://www.cfd-online.com/Forums/ope...tml#post586823

Best regards,
Alex

Melting in a body-fixed reference frame
 

Hi,
first I would like to thank for this very helpful thread.

I want to simulate a melting problem and I just thought that someone of you might help me.
A heat source is embedded into a phase change material and the heat source moves with a constant and given velocity. To solve for the phase change with convection, I use a solver based on Fabian Rösler's solver which was posted in this thread. I would like to use a fixed grid with a heat source fixed reference frame, so that the phase change material moves relative to the heat source. When using just an inlet and outlet condition for the velocity, the velocity changes within the solid phase, which is unphysical. I think the reason for this is mass conservation. Another possibility would be to add the velocity in the darcy term but this seems also not to work. Do you have any ideas how i can treat this relative motion phase change problem?

Thanks in advance!

@tetra-eder. Unfortunately I have not worked much with moving reference frame simulations yet in OpenFOAM so I don't have a answer to your question readily available for you.

Maybe if you would detail a bit more the simulation you want to achieve it will be easier for the forum to answer you.

If I understand you correctly, your heat source is moving in a static fluid? So you should be able to simulate that with an inlet, outlet boundary condition and let the fluid move instead of the heat source. However where is the solid phase in in your simulation? The term "heat source" implies that you want to melt something right? Or do you want to freeze the liquid onto the moving heat sink?

As you can see, a bit more detail might help.

One option which comes to mind is that you can also use a cyclic boundary condition for the inlet and outlet and use the fvOption "momentumSource" with a "meanVelocityForce" type to prescribe a fixed flow rate in your simulation for the fluid. However if you do that and keep the temperature field also cyclic, then you will effectively heat the fluid with your heat source as no thermal energy will escape the system.

Hope this helps somewhat.

Cheers,
Alex