Modeling Surface Reaction (CVD) on ANSYS Fluent

In summary, the speaker is seeking help with modeling a single surface reaction in Ansys and Fluent for a CVD reactor. The desired reaction is CH4 (g) -> C(s) + 2H2 (g). However, the speaker is unsure of how to set up the mixture and reaction, particularly with regards to 'site' and 'solid' species. The process may be more complex than initially thought, with possible reactions including CH4 (g) -> CH2 (g) + H2 (g) and CH2 (g) -> C(s) + H2 (g). The speaker is looking for guidance on how to approach this problem.
  • #1
grapheeene
1
0
Hi guys,

First of all, thank you for your help. I am new in Ansys and Fluent (less than a month), hoping to learn.

I am trying to model a simple and single surface reaction

CH4 (g) -> C(s) + 2H2 (g)

on a "CVD reactor" to grow C(s) (graphene, or graphite). The inlets are gases inyections of Ar and CH4 at the top of the CVD, and two thin parallel Cu surfaces are in the center (the catalyst), where C would be deposited. I am trying to model the growth of C(s) and the amount of H2 on the entire region, with and without thermodifussion (Soret).

The question is that I have some trouble with setting up the mixture and the reaction. I have a confusion with 'site' and 'solid' species in this case, and with reactions and mechanisms (since it's only superficial). I need the system to stop generating H2 when the surface is full of C(s).

Can you guys give me some basic steps to start this?? I don't know how to get the adsorption done. Do I need another reaction??

I guess this problem is not hard to be solved. Thanks so much for your help!
 
Engineering news on Phys.org
  • #2
grapheeene said:
I am trying to model a simple and single surface reaction

CH4 (g) -> C(s) + 2H2 (g)
I don't believe the process is that simple. From what I've seen in the literature, the process may be more like:

CH4 (g) -> CH2 (g) + H2 (g)

CH2 (g) -> C(s) + H2 (g)
 
  • #3
It is even more detailed (20 reactions or more), but I want to compute a single reaction, and I don't know which reactions to write and what 'site' and 'solid' species to create, in order to get the model done.
 

FAQ: Modeling Surface Reaction (CVD) on ANSYS Fluent

1. What is CVD and how is it modeled in ANSYS Fluent?

CVD stands for Chemical Vapor Deposition, which is a process used to deposit thin films of materials onto a surface using chemical reactions. In ANSYS Fluent, CVD is modeled using a combination of species transport, surface reactions, and energy equations.

2. What are the key parameters that need to be defined for modeling CVD in ANSYS Fluent?

The key parameters for modeling CVD in ANSYS Fluent include the gas phase species concentrations, surface reaction rates, temperature, pressure, and flow velocity. These parameters can be defined through user inputs or obtained through experiments or literature data.

3. How does ANSYS Fluent account for the surface chemistry in CVD modeling?

ANSYS Fluent uses surface reactions to account for the surface chemistry in CVD modeling. These reactions can be defined as chemical reactions or as surface reactions between gas phase species and solid surface sites. The rates of these reactions are dependent on the surface reaction rate coefficients and the concentration of the species involved.

4. What are the challenges in modeling CVD using ANSYS Fluent?

One of the main challenges in modeling CVD in ANSYS Fluent is accurately capturing the complex physics involved in the process. This includes the transport of species, heat and mass transfer, and surface chemistry. Another challenge is obtaining accurate input parameters, such as reaction rates and surface properties, which can significantly affect the results.

5. Can ANSYS Fluent be used to optimize CVD processes?

Yes, ANSYS Fluent can be used to optimize CVD processes by allowing for the simulation of different operating conditions and input parameters. By analyzing the results of these simulations, the most optimal conditions for the CVD process can be determined, leading to improved efficiency and cost-effectiveness.

Similar threads

Back
Top