Learning Forum

[mahendrark]

Hi guys!

So I'm trying to use S2S radiation model for my 2D flat plate solar thermal collector and I have some outstanding queries about implementing this model properly. Would appreciate it if you guys can help answer some of my questions.

1. When choosing the maximum number of radiation iterations and energy iterations per radiation iteration, I'm currently going with 30 and 40 respectively. Is there a rule of thumb here or what I'm doing is okay? I choose 30 for the former because the radiation residual only converges with 24 iterations.

2. Giving emissivity values: For some edges (not surfaces because its 2D), I could only declare the emissivity value for the shadow boundaries. Like for e.g., absorber sheet top and bottom edges (both in contact with fluid zones), in the boundary conditions, Fluent only lets me give emissivity values for top_shadow and bot_shadow and not to top and bot. Is something wrong here, or is it okay?

3. y professor told me long time ago to first run the model without radiation model (S2S in this case) ON and after a few thousand iterations, to switch ON the S2S model. Is that the right approach?

Thanks a ton in advance!