Discussion Forum

Hi

indeed he Ice phase change model is not in the 4 library, but perhaps the HT Continuous Casting model can give you some clues

--
Good luck
Ivar

Thanks you very much for the precious hint!

Now I have another question:
in the continuous casting model they said that the difference between solid and liquid Cp (apart for the fusion latent heat) is given by a dH/T_m (applied with an Heaviside function) where
dH=205 kJ/(kg K) is the latent heat
T_m= 1356 is the melting temperature
so that

Cp(solid)=380[J/(kg K)]
Cp(liquid)= 380+dH/T_m=530 [J/(kg K)] as requested.

I really don't know if this Cp difference given by dH/T_m is a well know formula, but for sure is not true for water:
Cp(solid)= 2052[J/(kg*K)]
Cp(liquid)= 4179[J/(kg*K)]
dH=333 kJ/kg
T_m=273.15 K

so, do you think that I could apply for water in this way?
Cp=Cp1+D*dH
D exp(-(T-T_m)^2/(dT^2))/(sqrt(pi)*dT)
Cp1 2052[J/(kg*K)]+(4179-2052)[J/(kg*K)]*flc2hs((T-T_m)[1/K],dT[1/K])

Thanks you very much

Hi

there are a few other treads and I believe some models onthis already. One way to mimic a phase change is to have a steep gradient + pulse on the Cp over 0.5 or 1K around the transition temperature, such that integrated over T your CP valus takes into account both solid and liquid and an intermediate phase absoring the latent heat energy

Test out your functin as an analytical function + a simple 1m^3 model and integrate over a simple case to check that total energy in to go from -1°C to +1°C sums up to 1K of enthalpy liquid + 1K of enthalpy solid + latence energy for your given volume* density

--
Good luck
Ivar

Thanks you again,

I have reached my objective and I was able to put both the step and the pulse directly inside the material definition.
Now I would like also to implement directly in the material a property for the fraction of liquid phase that could be "seen" in the results directly without creating a global defined function for the model... I will study on this.

I had also problem in cathing the transition in a time dipendent simulation, but on onother thread I found the trick to force the temporal step of the simulation, and now it's working fine!

Hi

hat's good to hear and how it all should be ;)
Searching the forum is slightly tedious, but there are really a lot of nice tips and trick around

--
Good luck
Ivar

Hi

I am working on a similar project, trying to model a solid-liquid phase change in a semiconductor in 2-D radial symmetry. Much like water, there is a 5% volume decrease going from solid to liquid. I already understand how to mimic phase change in terms of the material properties and incorporating the latent heat of fusion into the heat capacity function.

I am trying to model the volume change (*with moving mesh*) that is associated with this phase change. I am unsure of which physics modules I need to set this up. I took a look at the Continuous Casting model (which uses the "Non-Isothermal Flow" module), but it doesn't exactly apply to my case as:
1) There is no constant flow of the fluid in my case , it is a solid semiconductor and is being melted with Joule Heating
2) There was no volume change in their case, they used the same mass density for solid and liquid cases

My goal is to start with something simple - just melting a block of the semiconductor on top of a substrate (think of an ice cube melting on a table). I want to see the mesh moving such that volume reduces and the shape deforms to look like a bead of liquid rather than having right angles on the edges. Eventually I will try to model this in the environment of the device where the semiconductor is enclosed by other materials and voids of empty space will form.

I would appreciate it if someone could let me know which physics modules I need for this type of problem.
Thanks
Adam