{"id":171051,"date":"2023-06-05T07:05:36","date_gmt":"2023-06-05T07:05:36","guid":{"rendered":"\/knowledge\/forums\/topic\/tips-for-resolving-unphysical-temperatures-and-poor-convergence-with-cht-cases-2\/"},"modified":"2023-07-31T12:29:56","modified_gmt":"2023-07-31T12:29:56","slug":"tips-for-resolving-unphysical-temperatures-and-poor-convergence-with-cht-cases-2","status":"publish","type":"topic","link":"https:\/\/innovationspace.ansys.com\/knowledge\/forums\/topic\/tips-for-resolving-unphysical-temperatures-and-poor-convergence-with-cht-cases-2\/","title":{"rendered":"Tips for resolving unphysical temperatures and poor convergence with CHT cases."},"content":{"rendered":"

Problems with a CHT analysis in CFX can manifest themselves as unphysically high temperatures in a solid due to poor mesh quality of that solid. If very high temperatures are generated, use CFD-Post to isolate the location of concern then check the mesh quality in this area. If the minimum orthogonality angle is less than 10 degrees in this area, try to remesh it to improve the quality. It has also been shown that resolving the temperature gradient near the interface with inflation layers will help. Unphysically high temperatures near the fluid solid interface can also be caused by the use of 1:1 interfaces. A conformal mesh can be used for CHT cases, however if unphysically high temperatures are encountered, GGI interfaces should be used. If convergence problems and\/or unphysical temperature peaks persist the recommendation is to change the diffusion scheme used with the CHT model. To do this, you need to use the expert parameter ‘”cht diffusion scheme”. A more robust but less accurate scheme (positive definite values) is used if the parameter is set to: EXPERT PARAMETERS: cht diffusion scheme = 3 END<\/p>\n","protected":false},"template":"","class_list":["post-171051","topic","type-topic","status-publish","hentry","topic-tag-4422","topic-tag-cfx","topic-tag-cht","topic-tag-fluid-dynamics","topic-tag-heat-transfer-and-radiation","topic-tag-modeling-setup-advice"],"aioseo_notices":[],"aioseo_head":"\n\t\t\n\t\n\t\n\t\n\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t