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Young December 16, 1999 02:24

solidification process
Hi1 I'm doing a cfd analysis of solidification process using STAR-CD V3.10

I would like to know how can I model the interface region (what we called 'mushy zone').

I welcome your comments for this case. Regards,


Sanjeeb pal December 18, 1999 15:31

Re: solidification process
I assume you are using the enthapy formulation and are solving for porosity also. I once thought of using STAR to do something similar. Could you post more details about the implementation in STAR.

Hong December 19, 1999 15:06

Re: solidification process
Hi, I don't know STAR-CD, I can only say something according to my experience.

firstly, you should compute the temperature field with energy conservation equation, by using this equation, you are supposed to know the relationship between the temperature and solid fraction, f-T curve.

secondly, you can use porous media theory to simulate the mushy zone, suppose you know the relationship between the solid fraction and pressure resistance (Darcy formula).

thirdly, you can include the component redistribution during solidification, and then you can compute the liquidus and solidus with the contents of components.

forthly, suppose you include the third step, then you can get a good approximation of the f-T curve, this is important for accuratly modeling.

fifthly, thermal and solutal bounancy should be included, just by Bousinesque's assumption.

sixthly, you should consider whether to employ the assumption of 'equilibrium solidification'.

seventhly, turbulence model in mushy zone is unknown, you can employ any turbulence model as you like, and then you can say a lot of words to prove your validity.

eighthly, you 'd better use a fine grid to model the mushy zone since the mushy zone is usually very thin and quite unstable, I think this is very important.

ninthly, it is better to employ a fast solver in this simulation, maybe this is the most difficult part.

Good luck


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