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Set Stefan condition manually

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Hello,

I'm currently struggling with stefan problem and want to implement the stefan condition L(V.n)=Kl grad(T).n-Ks grad(T).n manually on the Solid/Liquid interface. L is latent heat, V is interface velocity.

I figured out there could be 2 possible ways:
(1) HT in liquid with solid subnode defined in this physics;
(2) 2 HTs, one is HT in solid and the other is HT in liquid and set;

for (1), since the default continuity condition assigns Kl grad(T).n-Ks grad(T).n=0, how to override this to add the latent heat term?

for (2) Do I need to define temperature and flux for both HTs in their boundary settings?

Thanks in advance for any suggestion!

4 Replies Last Post 3 avr. 2014, 11:44 UTC−4

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Posted: 1 decade ago 1 avr. 2014, 02:13 UTC−4
Hello,

I have never met your problem and have not checked for a solution, but for (1), what about using 'Form Assembly' instead of 'Form Union' in order to break continuity at the interface solid/liquid?

Benjamin
Hello, I have never met your problem and have not checked for a solution, but for (1), what about using 'Form Assembly' instead of 'Form Union' in order to break continuity at the interface solid/liquid? Benjamin

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Posted: 1 decade ago 1 avr. 2014, 09:33 UTC−4

Hello,

I have never met your problem and have not checked for a solution, but for (1), what about using 'Form Assembly' instead of 'Form Union' in order to break continuity at the interface solid/liquid?

Benjamin


Thank you, Benjamin. I also got to know that in 'Form Union' geometry, the temperature and flux continuity is default, so I used 'Form assembly'.
Now my problem is how to impose the stefan condition Ks*ht2.ntflux_u-Kl*ht2.ntflux_d+speed*nx*Lm on the solid/liquid interface. The model in 4.3b is attached and the S/L interface is assumed to be fixed here.

Appreciate any suggestion.

[QUOTE] Hello, I have never met your problem and have not checked for a solution, but for (1), what about using 'Form Assembly' instead of 'Form Union' in order to break continuity at the interface solid/liquid? Benjamin [/QUOTE] Thank you, Benjamin. I also got to know that in 'Form Union' geometry, the temperature and flux continuity is default, so I used 'Form assembly'. Now my problem is how to impose the stefan condition Ks*ht2.ntflux_u-Kl*ht2.ntflux_d+speed*nx*Lm on the solid/liquid interface. The model in 4.3b is attached and the S/L interface is assumed to be fixed here. Appreciate any suggestion.


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Posted: 1 decade ago 2 avr. 2014, 02:10 UTC−4
If I were you, I would try to add an 'heat flux' sub-node in the node 'continuity' to override the thermal insulation at the interface liquid/solid. There, you can specify q0 regarding to your needs.

Not sure if it could work in your case. Keep me informed, I am interested.
If I were you, I would try to add an 'heat flux' sub-node in the node 'continuity' to override the thermal insulation at the interface liquid/solid. There, you can specify q0 regarding to your needs. Not sure if it could work in your case. Keep me informed, I am interested.

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Posted: 1 decade ago 3 avr. 2014, 11:44 UTC−4

If I were you, I would try to add an 'heat flux' sub-node in the node 'continuity' to override the thermal insulation at the interface liquid/solid. There, you can specify q0 regarding to your needs.

Not sure if it could work in your case. Keep me informed, I am interested.


Hello, Benjamin,

Thanks for your advise. Actually I've tried to override the thermal insulation in 'Continuity' node, but it is still a little confused to me because in the Assembly geometry form, the interface of Solid and Liquid actually contains both solid and liquid domain boundary. It seems to me I have to assign heat flux to these two boundaries respectively.

An alternative way to walk around is to assign a heat source (actually a heat sink) on the solid/liquid interface, the source value q=-rho*Lm*(Vx.nx+Vy.ny), rho is density, Lm is latent heat, Vx Vy are interface velocity. In this case, I just use Union geometry to take advantage of its default interface continuity setting. I guess it's less confused to use this method than the previous idea.

Pls point me out if I'm wrong.

Appreciate your help.

X. Cao
[QUOTE] If I were you, I would try to add an 'heat flux' sub-node in the node 'continuity' to override the thermal insulation at the interface liquid/solid. There, you can specify q0 regarding to your needs. Not sure if it could work in your case. Keep me informed, I am interested. [/QUOTE] Hello, Benjamin, Thanks for your advise. Actually I've tried to override the thermal insulation in 'Continuity' node, but it is still a little confused to me because in the Assembly geometry form, the interface of Solid and Liquid actually contains both solid and liquid domain boundary. It seems to me I have to assign heat flux to these two boundaries respectively. An alternative way to walk around is to assign a heat source (actually a heat sink) on the solid/liquid interface, the source value q=-rho*Lm*(Vx.nx+Vy.ny), rho is density, Lm is latent heat, Vx Vy are interface velocity. In this case, I just use Union geometry to take advantage of its default interface continuity setting. I guess it's less confused to use this method than the previous idea. Pls point me out if I'm wrong. Appreciate your help. X. Cao

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