Learning Forum

[jovan teo]

Hi Ansys help,

I'm trying to simulate the freezing of PCM encapsulated in plastic, after prolonged contact with water.

I've reduced my model into 2D (not sure how to do it best in 3D). Green - water, Brown - plastic, Grey - PCM

These are the conditions:

1. water flow at 2mm/min at 5 degreeC
2. PCM initial temp at 9 degreeC
3. PCM liquidus and solidus temp are 7 and 8 degreeC respectively

My named selections are:

1. face: inlet, outlet, water outer wall, pcm wall, plastic wall
2. interior: water, plastic, pcm

Material:

Boundary Conditions:

1. inlet with velocity and temp
2. outlet: outflow
3. wall: water wall temp of 5 degreeC

Initialisation - 9 degreeC compute from PCM wall

After running, the liq fraction of the PCM wall is always at 1 and the temp is always at 9 degreeC

And when i try to set the pcm wall, plastic wall to coupled, the temp and liq fract graphs goes brrrr with floating point exception error

I know I'm doing something (alot) wrong but I'm not sure what. Please help me, I would greatly appreciate it :D

[Rob]

If you're flowing water into the green section you need to extend the domain and significantly increase the mesh resolution. The above looks like the solver is not happy, and you're basically bouncing off the limiters of temperature as the solution doesn't quite crash. You may also want to look at thin wall options in Fluent as you may not need to consider the plastic as a solid zone.