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Set Stefan condition manually
Posted 31 mar 2014, 23:12 GMT-4 Heat Transfer & Phase Change, Heat Transfer, Parameters, Variables, & Functions Version 4.3b 4 Replies
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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!
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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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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.
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Not sure if it could work in your case. Keep me informed, I am interested.
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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