{"id":294683,"date":"2023-07-25T10:43:18","date_gmt":"2023-07-25T10:43:18","guid":{"rendered":"\/forum\/forums\/topic\/negative-total-heat-transfer-imbalance\/"},"modified":"2023-07-25T10:43:18","modified_gmt":"2023-07-25T10:43:18","slug":"negative-total-heat-transfer-imbalance","status":"closed","type":"topic","link":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/negative-total-heat-transfer-imbalance\/","title":{"rendered":"Negative total heat transfer imbalance"},"content":{"rendered":"<div>In Fluent, I am currently working on a heat transfer case involving two phases: coolant oil and air. The simulation includes the spraying of oil onto a metal geometry using a jet nozzle. The metal geometry has a heat source of 24 W, causing it to heat up to an average temperature of 90&deg;C. The coolant oil is injected into the domain at a temperature of 40&deg;C, and the surrounding area is filled with air at 20&deg;C. To replicate the lab experimental setup accurately, I have extended the model to encompass a very large surrounding area around the metal geometry. The intention behind this is to account for the effects of natural convection cooling.<\/div>\n<div>&nbsp;<\/div>\n<div>For the simulation, I have set up the following boundary conditions: a velocity inlet with a volume fraction of 1 for the oil, a pressure outlet with a volume fraction of 1 for the backflow air at 20&deg;C. all other boundaries are adiabatic.&nbsp;<\/div>\n<div>&nbsp;<\/div>\n<div>The simulation is conducted in a steady-state manner, and I have utilized the SST k-omega turbulence model. &nbsp;The multiphase model is VOF Implicit with implicit body force, VOF boundary is dispersed. The mesh incorporates 10 boundary layers, and all walls have a y+ value below 4, while the walls of the metal geometry have a y+ value below 1.<\/div>\n<div>&nbsp;<\/div>\n<div>Currently, when calculating the total heat transfer imbalance, which considers the contributions from the inlet, outlet, and energy source, I am obtaining a value of -11W.&nbsp; I am guessing this is because the cooling effect from the large surrounding air domain is not calculated here.&nbsp;<\/div>\n<div>&nbsp;<\/div>\n<div>My question is whether my assumption is correct, and if so, how can I incorporate the natural convection heat transfer from the surrounding air into the energy transfer imbalance calculation?<\/div>\n","protected":false},"template":"","class_list":["post-294683","topic","type-topic","status-closed","hentry","topic-tag-multiphase_models-1","topic-tag-boundary-conditions","topic-tag-fluid-solid-heat-transfer","topic-tag-heat-transfer","topic-tag-heat-transfer-rate-2","topic-tag-imbalance-1"],"aioseo_notices":[],"acf":[],"custom_fields":[{"0":{"_bbp_subscription":["265715","199"],"_bbp_author_ip":["23.217.200.46"]," _bbp_last_reply_id":["0"]," _bbp_likes_count":["0"],"_btv_view_count":["1125"],"_bbp_topic_status":["unanswered"],"_bbp_status":["publish"],"_bbp_topic_id":["294683"],"_bbp_forum_id":["27792"],"_bbp_engagement":["199","265715"],"_bbp_voice_count":["2"],"_bbp_reply_count":["15"],"_bbp_last_reply_id":["301365"],"_bbp_last_active_id":["301365"],"_bbp_last_active_time":["2023-08-14 13:53:09"]},"test":"w-maddumageherts-ac-uk"}],"_links":{"self":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/topics\/294683","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\/294683\/revisions"}],"wp:attachment":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/media?parent=294683"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}