Cooling rate representation method

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shaojielv
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Cooling rate representation method

Post by shaojielv » Tue Apr 13, 2021 6:28 am

Everybody is good:
First of all, as a beginner of Micress software, I am very happy to join our big family.I met some problems in the process of learning. I hope I can get your help.
In the process of learning software, I noticed that the cooling rate in MICRESS was expressed directly through a specific numerical value, but I did not find that the cooling rate could be expressed in the equation when I derived the multiphase field equation, so I did not know whether the cooling rate could be reflected in the equation.But I thought that since the cooling rate can be defined in the phase field, it should be able to be expressed in the equation, but I didn't find the cooling rate in the equation.I do not know whether my understanding is correct, if there is a friend who knows, can you help me answer this question?I would greatly appreciate your help.
Wish you a happy life!

Yours:Lv shaojie

Bernd
Posts: 1504
Joined: Mon Jun 23, 2008 9:29 pm

Re: Cooling rate representation method

Post by Bernd » Tue Apr 13, 2021 10:53 am

Dear Lv shaojie,

The phase-field equation of MICRESS is based on a Helmholtz energy approach, which means that temperature is an independent variable and thus is considered as a boundary condition. This means, that most typically temperature is defined as an initial temperature cooling rate, although MICRESS also provides other types of thermal boundary conditions (implicit calculation from latent heat, time-dependent profiles, 1d-temperature field calculation ...). This is in contrary to some entropy based phase-field models where T is a dependent variable and thus changed implicitly.

In our phase-field equation, the temperature boundary condition primarily appears in the chemical driving force which is strongly T-dependent. Furthermore, there may be a T-dependency of the interface mobility and of the interface stiffness.

Bernd

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