[arashsilver]

Originally Posted by B.Hamada

Thank you
But i have a question, i have two data one for solid phase and the other for the liquid phase, for example there is a liquid density and a solid density, the same for the Specific heat capacity, and the Thermal conductivity.
but in fluent, I can enter the parameters of a single-phase.
please, what can i do?

Oh, I'm suffering from exactly the same problem and I'm a newbie :-(
Did you find any solution to this? If so, please help me.

Regards
Arash

[parsa]

Originally Posted by arashsilver

Oh, I'm suffering from exactly the same problem and I'm a newbie :-(
Did you find any solution to this? If so, please help me.

Regards
Arash

This is my question as well; as I am fairly new user of ANSYS Fluent. Does anybody can help?

Thanks in advance,
Parsa

[rzyz]

Originally Posted by HamidIran

Hi Hamada,

Depending on the melting temperature that you define for your PCM in Materials tabs and the initial temperature you set in the "Solution Initialization" tab, the initial state of PCM is automatically determined. For example, if your PCM melting point is 309<Tm<311, if you set the initial temperature to 308, the PCM will start from solid phase. If your initial temperature is 312 the initial PCM phase will be liquid, and if the initial PCM temperature is 310, the initial volume fraction of liquid phase will be 0.5.

I hope this helps.

Hamid

Do you know the reason for usual selection of an initial temperature of the PCM higher than the liquid temperature in the case of fully liquid or lower than the solidus temperature in the case of the fully solidified rather than using the exact PCM solidus and liquidus values in FLUENT? As I know the FLUENT considers the liquid fraction = 1 for the liquidus temp and 0 for the solidus temp. Is this just related to the accuracy of the results and just to ensure convergence?

[rzyz]

Originally Posted by HamidIran

Hi Hamada,

Depending on the melting temperature that you define for your PCM in Materials tabs and the initial temperature you set in the "Solution Initialization" tab, the initial state of PCM is automatically determined. For example, if your PCM melting point is 309<Tm<311, if you set the initial temperature to 308, the PCM will start from solid phase. If your initial temperature is 312 the initial PCM phase will be liquid, and if the initial PCM temperature is 310, the initial volume fraction of liquid phase will be 0.5.

I hope this helps.

Hamid

Do you know the reason for usual selection of an initial temperature of the PCM higher than the liquid temperature in the case of fully liquid or lower than the solidus temperature in the case of the fully solidified rather than using the exact PCM solidus and liquidus values in FLUENT? As I know the FLUENT considers the liquid fraction = 1 for the liquidus temp and 0 for the solidus temp. Is this just related to the accuracy of the results and just to ensure convergence?

[vijayknmodi]

can any one have have the steps for melting of ice in ansys fluent .. please share the steps

[svk]

In order to give different thermal properties for solid and liquid phases. I think the following description may do the task.
If you take density not as a constant value but as a function of temperature (say piecewise linear function), you can set one value for below melting point (i.e. for solid) and one value for above.

[svk]

Originally Posted by B.Hamada

Thank you
But i have a question, i have two data one for solid phase and the other for the liquid phase, for example there is a liquid density and a solid density, the same for the Specific heat capacity, and the Thermal conductivity.
but in fluent, I can enter the parameters of a single-phase.
please, what can i do?

In order to give different thermal properties for solid and liquid phases. I think the following description may do the task.
If you take density not as a constant value but as a function of temperature (say piecewise linear function), you can set one value for below melting point (i.e. for solid) and one value for above.

[aestas]

Originally Posted by beer

Hi zbc19910519

Sure. Just use a very strong force, which is velocity dependent. For example 1e10*(vx-1) if you want your velocity component in x-direction to be 1. Just remember to tell the solver the derivative of this equation (I think it is called Source Coefficient in Fluent), otherwise the source will blow up your calculation. The solver uses the derivative to include the force in the implicit part of the solver (see Patankar).

Cheers

Hi, beer.

I am trying to solve a similar problem,like ice melt.
In order to solve the move of solid, i try to add a gravity force source to the y momentum.

DEFINE_SOURCE(solid_source, cell, mix_th, dS, eqn)
{
real source;
cell_t c;
real x[ND_ND],r;
real m_lg,a,b;
Thread *pri_th, *sec_th;

pri_th = THREAD_SUB_THREAD(mix_th,0);
sec_th = THREAD_SUB_THREAD(mix_th,1);

m_lg = 0.0;

if (C_LIQF(cell,pri_th)==0)
{
m_lg = -9.8*C_R(cell,pri_th);
}
else
{
m_lg = 0;
dS[eqn] = 0;
}

return m_lg;
}

but still it did not move.

Can you help me?

[mehradahmadi]

Hi all, I want to do a project about Numerical simulation of heat exchangers with phase-change material with the help of Fluent.
For example, air from the inside of phase-change material between two parallel plates are passed, and We want more cool air to keep output As shown below:

What options should be activated and how that process performed?Please please help me , If it is possible….
thank you.

[HamidIran]

Originally Posted by B.Hamada

Thank you
But i have a question, i have two data one for solid phase and the other for the liquid phase, for example there is a liquid density and a solid density, the same for the Specific heat capacity, and the Thermal conductivity.
but in fluent, I can enter the parameters of a single-phase.
please, what can i do?

Hamada,

You need to specify temperature dependent properties for your PCM by using a UDF. I suggest you consult UDF manual for "property" related UDFs.

Hamid

[HamidIran]

Originally Posted by rzyz

Do you know the reason for usual selection of an initial temperature of the PCM higher than the liquid temperature in the case of fully liquid or lower than the solidus temperature in the case of the fully solidified rather than using the exact PCM solidus and liquidus values in FLUENT? As I know the FLUENT considers the liquid fraction = 1 for the liquidus temp and 0 for the solidus temp. Is this just related to the accuracy of the results and just to ensure convergence?

Rami,

If you set the initial temperature exactly equal to the liquidus temperature a very small temperature fluctuation due to round-off errors or any other numerical swing may result in dramatic change in the source terms related to the phase change and creates numerical instabilities. That's the only reason.

Good Luck,

Hamid

[djamila77]

Originally Posted by msaeedsadeghi

I have done that. It's easy, you may have done a great mistake.

hi there;

<i'm new in the domain
can you help me

thank you

[Shoonya]

Originally Posted by HamidIran

A large mushy zone constant enforces the velocity in solid phase to go to zero (or to pull velocity). If you set it to zero the solid phase will move with a velocity obtained from the solution of the N-S equations. However, it will deform like a liquid.

That is useful.... Thanks