{"id":388488,"date":"2024-10-08T07:37:46","date_gmt":"2024-10-08T07:37:46","guid":{"rendered":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/rpi-model-diverges-at-high-superheats\/"},"modified":"2024-10-08T07:37:46","modified_gmt":"2024-10-08T07:37:46","slug":"rpi-model-diverges-at-high-superheats","status":"publish","type":"topic","link":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/rpi-model-diverges-at-high-superheats\/","title":{"rendered":"RPI Model Diverges at high superheats"},"content":{"rendered":"<p>&lt;p&gt;Hello.&lt;\/p&gt;&lt;p&gt;My simulation is a channel flow for subcooled boiling. I am using the standard RPI model and have tried it with Tolubinski-konstanchuk dor Departure Diameter and Site Desnity and also with Kocamostafa. Kocamostafa predicts a lower volume fraction in the domain and converges well to a certain wall superheat. But instantly diverges when moving from applied heatflux of 4.5&nbsp; to 5 MW\/m^2.&lt;\/p&gt;&lt;p&gt;Tolubinski predicts a much higher volume fraction but has trouble converging at these heat fluxes and does not aloow further increase. I see that there is dependancy on the force models chosen. Ishii-Zuber predicts that increase in heat transfer and drop in wall temperature due to boiling phenomenon very well in conjuction with Antal and Burns Wall Lubrication and Turb Dispersion. This effect is not seen while using Kocamustafa.&lt;\/p&gt;&lt;p&gt;Also switching to Schiller Naumann, massively stabilizes the simulation but also loses this cooling effect that I am looking for trying to predict.&lt;\/p&gt;&lt;p&gt;So my preferred choice is Ishii-Zuber but the simulations diverge as I said earlier. Any insights and tips on how to work with this?&lt;\/p&gt;<\/p>\n","protected":false},"template":"","class_list":["post-388488","topic","type-topic","status-publish","hentry","topic-tag-boiling-flow-in-fluent","topic-tag-cooling-channels","topic-tag-divergence","topic-tag-subcooled-boiling-1"],"aioseo_notices":[],"aioseo_head":"\n\t\t<!-- All in One SEO 4.9.10 - aioseo.com -->\n\t<meta name=\"description\" content=\"Hello.My simulation is a channel flow for subcooled boiling. I am using the standard RPI model and have tried it with Tolubinski-konstanchuk dor Departure Diameter and Site Desnity and also with Kocamostafa. Kocamostafa predicts a lower volume fraction in the domain and converges well to a certain wall superheat. 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