{"id":254946,"date":"2020-12-04T14:18:06","date_gmt":"2020-12-04T14:18:06","guid":{"rendered":"\/forum\/forums\/topic\/combination-of-boundary-conditions-fixed-temperature-and-radiation-vacuum\/"},"modified":"2022-08-18T05:11:13","modified_gmt":"2022-08-18T05:11:13","slug":"combination-of-boundary-conditions-fixed-temperature-and-radiation-vacuum","status":"closed","type":"topic","link":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/combination-of-boundary-conditions-fixed-temperature-and-radiation-vacuum\/","title":{"rendered":"Combination of boundary conditions fixed temperature and radiation, vacuum"},"content":{"rendered":"

\"\" \"\"<\/p>\n

In the given example there is a metal pin enclosed by a tube (not displayed). Between the pin and the tube is supposed to be vacuum so that it is a non participating fluid. The planar front and back of this domain are insulated free slip walls to mimick a symmetry wall, as recommended in the Online Help.<\/p>\n

My first question is concerning the setup of the vacuum – idealy I would like to set a reference pressure to 0bar and apply a low static pressure. However I could not find the option to set a reference pressure. Is there a default setting for the operating pressure and can it be altered?<\/p>\n

The next question that occured to me is concerning the boundary conditions, mimicking the pin and tube walls. For the tube I would idealy set the outer wall to a fixed temperature and apply an emissivity of a certain value. However the addition of emissivity is only possible with a convection boundary condition. This made me wonder if applying this condition and setting the convection and radiation temperature to the fixed temperature will result in the same outcome. I might be misunderstanding the convection boundary condition and would be very grateful for a clarification.<\/p>\n

I was wondering the same about the boundary conditions for the pin. The temperature here is higher than that of the tube walls and is therefor emmitting radiation energy. Since I cannot (or am not aware of this option) apply a temperature to the solid pin and an emmisivity to its surface in combination with the fluid\u00a0simulation, I was wondering if it is possible to correctly run a simulation of this problem alltogether.<\/p>\n

 <\/p>\n

Thank you very much for all comments, clarifications\u00a0and inputs regarding this problem!<\/p>\n","protected":false},"template":"","class_list":["post-254946","topic","type-topic","status-closed","hentry","topic-tag-ansys-discovery","topic-tag-best-practices","topic-tag-fluid-solid-heat-transfer-3"],"aioseo_notices":[],"acf":[],"custom_fields":[{"0":{"_bbp_subscription":["278523"],"_bbp_likes_count":["0"],"_btv_view_count":["462"],"_bbp_topic_status":["unanswered"],"_bbp_status":["publish"],"_bbp_topic_id":["254946"],"_bbp_forum_id":["27789"],"_bbp_engagement":["202","278523"],"_bbp_voice_count":["2"],"_bbp_reply_count":["3"],"_bbp_last_reply_id":["263157"],"_bbp_last_active_id":["263157"],"_bbp_last_active_time":["2021-02-10 13:00:27"]},"test":"klara-marekdraeger-com"}],"_links":{"self":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/topics\/254946","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/topics"}],"about":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/types\/topic"}],"version-history":[{"count":0,"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/topics\/254946\/revisions"}],"wp:attachment":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/media?parent=254946"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}