Convergence Problems


#1

Hello,

I am trying to model a burner that has a constant heat flux on the top of the disk in the center of the model. I have defined all the contact points and the properties of the materials. I also have lowered the timestep, and I am still running into convergence issues. I am very new to FEA analysis and some help would be greatly appreciated.

Project Link: https://www.simscale.com/workbench?publiclink=e97d42a0-3278-477c-88c5-d90f9efb8493

Thank you.


#2

Hi @jopoy,

Thanks for posting your question and welcome to SimScale - @cjquijano, @ahmedhussain18 could you have a look?


#3

Hi @jopoy and @AnnaFless!

I managed to have a successful run. It seems like the problem was in temperature residuals being exploding. This was due to high heat change in the system as there was a source but no sink.

I reran the simulation having also convection applied on the outer surfaces and this did work. This convection represents as if air is touching those surfaces and taking out heat from the system. Higher the convection coefficient, more dominant will be the convection effect. Moreover, I also merged the stainless steel solids in to one to make the simulation setup more simple. Please note that I have used advanced solver in this case as the normal solver was giving some problem related to non-positive Jacobian which is a known problem of non-advanced solver.

Please find the project here: BSF Burner - SimScale

Hope this helps. In case of question/s, feel free to ask.

Best,
Ahmed


#4

Hi Ahmed,

Thanks for the setup! It looks great! I eventually got the simulation running because I forgot to include convection through the water-cooling channels. I’m am pleased with my results for now, but I’m looking into your CHT simulation to model the flow of water an inlet water temp with a given flow rate along with the heat flux loads in my original project. I’ve started a new CHT project but I am just running into issue with the multiregion mesh. This is the CHT Project: https://www.simscale.com/workbench?publiclink=9d181106-8c03-4c09-a830-7ca7237ca8b9

Thanks.


#5

HI @jopoy!

As I am not a CFD expert, @Ali_Arafat @SamPrabhu might help you here.

Best,
Ahmed