Learning Forum

[ZoeYuan]

Hi,

I am simulating catalytic surface reaction of CO, C3H6 and NO in a micro-channel model. There are two domains in my model: the fluid domain which is the reacting flow and the solid domain which is the channel wall. I set coupled interface and then two contact regions auto-generated under the wall boundary conditions with the name of contact_region-src and contact_region-trg. I would like to ask if I want to set heat convection for the interface, do I need to set the heat transfer coefficient for the src side or trg side?  Also, do I need to set the material name here to be my channel wall material which is ceramic. 

Here is the screenshot of my boundary conditions. 

Regards,

Zoe

[Rob]

Moved to new thread.

If you have a coupled wall between fluid & solid Fluent should calculate the convective heat transfer. If you set a value you're artificially fixing something that's a function of the fluid flow. 

[ZoeYuan]

Hi rwoolhou,

Many thanks for your reply. 

Does this mean that I don't need to set anything for the thermal condition once I created a coupled wall between fluid & solid and just leave it blank?

Regards,

Zoe

[Rob]

Yes: you should leave that as coupled. I'd also review the wall thermal boundary conditions and shell conduction: do you really need to model the solid bit?

[ZoeYuan]

Hi rwoolhou,

Thanks for your quick reply.

This is a simplified version of my model. The original model is a heat exchanger and I need to consider the effect of different wall material on heat transfer between the flow and wall. Also, I am simulating catalytic surface reaction. In this case, do you think it's necessary for me to model the solid domain?

Regards,

Zoe

[Rob]

Difficult to say: partly because I can't see the model but also I'm not allowed to give detailed advice due to US export law. 

Heat transfer from the fluid to solid is handled in the solver & wall functions: avoiding an interface there is a good idea but not a requirement.  Also read up on y+ and wall functions (turbulence sections of the manual). 

Heat through the solid is a function of the material conductivity and surface area: we can use thin walls with a thickness, shell conduction or solid zones. 

[ZoeYuan]

Many thanks for your explanation. 

I need to consider the heat dissipation from the channel wall to surrounding environment -air. In this case, do I need to construct an enclosure surrounding my model to represent the heat dissipation from wall to air? Or is there any other way to simulate the heat dissipation? 

Regards,

Zoe