{"id":283522,"date":"2023-05-11T22:41:16","date_gmt":"2023-05-11T22:41:16","guid":{"rendered":"\/forum\/?post_type=topic&p=283522"},"modified":"2023-05-11T23:24:14","modified_gmt":"2023-05-11T23:24:14","slug":"solar-load-model-on-ansys-fluent","status":"closed","type":"topic","link":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/solar-load-model-on-ansys-fluent\/","title":{"rendered":"Solar Load Model on ANSYS Fluent"},"content":{"rendered":"

Hello,<\/p>\n

I am running a solar model and have some questions regarding absorptivity\/emissivity definitions in the solar load model. <\/p>\n

I am using solar ray tracing currently. I understand that solar ray tracing doesn’t take part in radiative heat transfer modeling, and merely taking the solar boundary condition as a heat flux input. However, we do still have the option to set semi-transparent and opaque surface for our model. Attached is a figure of my current model in Fluent. <\/p>\n

<\/a><\/span><\/strong><\/p>\n

Body 1 is a surface that takes solar irradiation, defined in the solar load model. This is a semi transparent surface with absorptivity and transmissivity defind.<\/p>\n

Body 2 is also a semi-transparent surface with absorptivity and transmissivity defined.<\/p>\n

Body 3 is an opaque surface with absorptivity defined.<\/p>\n

Body 4 is a semi-transparent surface with absorptivity and transmissivity defined.<\/p>\n

Body 5 is a semi-transparent surface with absorptivity and transmissivity defined.<\/p>\n

Body 6 is an opaque surface with absorptivity defined.<\/p>\n

Water acts as a heat sink in this model. <\/p>\n

Now my goal with my this study is to change the absorptivity of material surface 6. What I would expect from this study is that with higher absorptivity on the surface of body 6, I would get higher water temperature as well as higher temperature for body 6. However, it seems like it is the opposite of this. Keeping all my other BCs constant and changing only the absorptivity of body 6 to be a higher value, i found that the average water temperature decreases while the temperature of bodies 1-5 increased, which is the opposite of what I was expecting.<\/p>\n

The only reason I could think of is that Fluent might actually be considering absorptivity = emissivity in this case based on Kirchoff’s law. In this case, with higher absorptivity = higher emissivity, and more heat is emitted from surface of body 6 back up, hence the higher temperatures of body 1-5. I know this is true for S2S model, but im not sure if this is the case for solar ray tracing. If anyone has any directions on this, please do advice, thanks. <\/p>\n","protected":false},"template":"","class_list":["post-283522","topic","type-topic","status-closed","hentry","topic-tag-fluent","topic-tag-solar","topic-tag-solar-loading-2","topic-tag-solar-radiation","topic-tag-solar-ray-tracing-2"],"aioseo_notices":[],"acf":[],"custom_fields":[{"0":{"_bbp_author_ip":["23.39.172.6"],"_bbp_subscription":["273505","18096"],"_btv_view_count":["2301"],"_edit_lock":["1683847441:203963"],"_bbp_topic_status":["unanswered"],"_bbp_status":["publish"],"_bbp_topic_id":["283522"],"_bbp_forum_id":["27796"],"_bbp_engagement":["18096","273505"],"_bbp_voice_count":["2"],"_bbp_reply_count":["5"],"_bbp_last_reply_id":["283714"],"_bbp_last_active_id":["283714"],"_bbp_last_active_time":["2023-05-12 17:09:41"]},"test":"csl9r3umsystem-edu"}],"_links":{"self":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/topics\/283522","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\/283522\/revisions"}],"wp:attachment":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/media?parent=283522"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}