Phase change phenomena in Fluent v15

• Imane
In summary, when setting up a simulation to study the temperature change in PCM and HTF, you need to consider the geometry, meshing, and boundary conditions. The thermal conditions can be either convection heat transfer or heat flux, and the heat generation rate should be specified accordingly.
Imane
Hello everyone,
I am beginner in fluent v15, and I want to simulate the temperature change as a function of time in the phase change materials "PCM" and the heat thermal fluid "HTF" and the PCM fusion Front.
Regarding the geometry I chose to work with two coaxial tubes: the inner tube contains the heat thermal fluid and the outer tube contains the PCM
for meshing I appointed the input, output and symmetry area of HTF and PCM. Also the entry, exit and the symmetry of the wall between the PCM and the HTF
The set up steps followed are:
General ==> Type: based pressure, velocity formulation: absolute, time: transient
Model ==> volume of fluid with 2 stages in number eulerian, energy, melting and solidification
Materials ==> PCM characteristics: density, solidius and liquidus temperature , thermal conductivity, pure solvent latent heat and thermal expansion coefficient
for the HTF I chose to work with liquid water
Phases ==> Primary phase pcm, Secondary phase HTF
Cell Condition box ==> Wall (phase mixture, Type: Solid)
HTF (phase mixture type: Fluid, Fluid porosity: 1)
PCM (phase mixture type: Fluid, Fluid porosity: 1)
NB: I want to determine the porosity of the fluid depending on the temperature f (T)
- f(T) = 0 if T < Ts
- f(T) = 1 if T > Tm
- 0 < f(T) = (T -Ts) / (Tm - Ts ) < 1 if Ts < T < Tm
but I don't know how to do it with new input parameter
Boundary Conditions ==> in this stage I entered the HTF input velocity and the inlet and outlet temperatures of the HTF, PCM and WALL but I find myself stuck facing problem with the symmetry area of HTF and PCM.
and other boundary conditions appear as: wall-htf-wall, wall-htf-shadow-wall, wall-pcm, wall-pcm-wall, wall-pcm shadow-wall, wall-wall
but I do not know what to choose for thermal conditions: temperature convection heat flow or or ...
and if for example I chose the heat flux how can I calculate the heat generation rate and the heat flux.

I will be very grateful for your help and thank you in advance.

Best regards;

For the boundary conditions, you need to decide what type of thermal conditions you want to apply. If you want to use convection heat transfer, then you should select "Convective Heat Flux" as the boundary condition type. You can then enter the convective heat transfer coefficient and the ambient temperature, which are usually given in the problem statement or can be estimated using correlations.If you want to use a heat flux, then you should select "Heat Flux" as the boundary condition type. You can then enter the heat flux, which is usually given in the problem statement or can be estimated using correlations.Once you have selected the boundary condition type, it is important to make sure that the boundary condition is applied correctly. For example, if the boundary condition is applied to the wall, then the heat flux should be specified in the direction normal to the wall. Similarly, if the boundary condition is applied to the HTF or PCM, then the heat flux should be specified in the direction normal to the surface of the HTF or PCM.Finally, you also need to specify the heat generation rate. This is usually given in the problem statement or can be estimated using correlations.I hope this helps!

1. What is "Phase change" in Fluent v15?

"Phase change" in Fluent v15 refers to the physical process in which a substance changes from one state of matter to another, such as from solid to liquid or liquid to gas. Fluent v15 is a computational fluid dynamics software that can simulate and analyze these phase change phenomena.

2. Can Fluent v15 model phase change phenomena accurately?

Yes, Fluent v15 has advanced capabilities for modeling phase change phenomena, including the ability to accurately capture the interface between different phases and track the movement and distribution of each phase.

3. What types of phase change phenomena can be simulated in Fluent v15?

Fluent v15 can simulate a wide range of phase change phenomena, including melting, freezing, evaporation, condensation, and boiling. It can also model more complex phase change processes, such as solidification and sublimation.

4. How does Fluent v15 handle the energy transfer during phase change?

Fluent v15 uses a multi-phase flow solver that includes energy equations to accurately model the transfer of energy during phase change. This allows for a more realistic simulation of the phase change process.

5. Can Fluent v15 be used for industrial applications involving phase change phenomena?

Yes, Fluent v15 is commonly used in various industries, including aerospace, automotive, and energy, to simulate and optimize processes involving phase change phenomena. It can also be used to design and improve products that rely on phase change, such as heat exchangers and refrigeration systems.

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