Phase change process
 

Hello, everyone!

My name is Sang-Jin Lee, and I'm a graduate student studying in numerical heat transfer and fluid flow. I was engaged in a project that analysis the heat transfer processing, solidifying & melting, with Phase Change Material(PCM) just after finishing STAR-CD tutorial 3.1. two weeks ago. As you know, no example of PCM in STAR-CD tutorial, It was so hard for me even to find out a paper or an application related with Phase change method using STAR-CD. I think the key point in this problem is coding user sub-routine including mushy region and latent heat. But, in my poor knowledge from just STAR-CD tutorial, I have a no idea how to approach and which part in solution algorithm I have to modify. It's so important thing for me to fulfill this project successfully because I'm going to write my graduation essay by using STAR-CD application like this. Is there any method to solve this one? I'm behind of time. Any assistance or advice that you can give me will be greatly appreciated.

Thanks in advance.

Sang-Jin Lee

Re: Phase change process
 

Hi,

There are several user subroutine which are used to control the properties of the phase change:

DRHEAT: droplet heat DRMAST: droplet mass transfer

And also, DROICO is for the droplet initial condition.

Hopfully it is helpful.

Jing

Re: Phase change process
 

Thank U so much, Jing!

As U said, we have to use several user subroutine depending on the characteristic of a simulation. Let me say about my case briefly first,

A solid PCM is charged in the cylindrical can which is perfectly insulated around of its body except both sides. Suddenly temperature of one side will be changed, and the phase of PCM will be also changed gradually.

So I think the user routines U said, DRHEAT, DRMAST..., are not suitable here. I'm considering SORENT, SORMOM, DENSIT,VISMAL,CONVET,POSDAT in this case. Is my approach of this right?

Re: Phase change process
 

or you can use the COMET program , which is also available from Computational Dynamics.

Re: Phase change process
 

Hi,

the subroutines I suggested are suitable for the gas and liqid two phase flow with a phase change. For your case, please try the others. May be you can check the tutorial of the StarCD and find out a similar case.

Good Luck!

Jing

Re: Phase change process
 

In general, StarCD does not provide feature for solving solidification/melting phase change problem, because there is no such model included to provide such physics in Star. If Star is the only thing you can use to do it, there maybe something you can try (although I haven't try it myself). Use a subroutine to define when and where phase changes and account for the latent heat. In the solid phase, use subroutine to change fluid viscosity to infinity to freeze flow (so this is still single phase). However, you lose wall function if you want k-e turbulence model. Check out the enthalpy-porosity method to see if you can apply that in StarCD. Hope this would give you a lot trouble. and good luck.