{"id":381274,"date":"2024-09-01T15:35:22","date_gmt":"2024-09-01T15:35:22","guid":{"rendered":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/helical-fin-double-pipe-heat-exchanger-unexpected-temperature-contour-fluent\/"},"modified":"2024-09-01T15:41:24","modified_gmt":"2024-09-01T15:41:24","slug":"helical-fin-double-pipe-heat-exchanger-unexpected-temperature-contour-fluent","status":"publish","type":"topic","link":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/helical-fin-double-pipe-heat-exchanger-unexpected-temperature-contour-fluent\/","title":{"rendered":"Helical fin double pipe heat exchanger &#8211; Unexpected temperature contour (FLUENT)"},"content":{"rendered":"<p>&lt;div&gt;&lt;p&gt;I am trying to simulate the fluid flow inside a 1000mm long double pipe heat exchanger with helical fins. After running the simulation, I found that the results were quite unexpected.&lt;\/p&gt;&lt;\/div&gt;&lt;div&gt;&nbsp;&lt;\/div&gt;&lt;div&gt;&lt;p&gt;The following discrepancies were visible:&lt;\/p&gt;&lt;\/div&gt;&lt;div&gt;<\/p>\n<ul>&lt;\/div&gt;&lt;div&gt;&nbsp; &nbsp; <\/p>\n<li><strong>There is a sudden temperature drop in the inlet portion of the hot water.<\/strong><\/li>\n<p>&lt;\/div&gt;&lt;div&gt;&nbsp; &nbsp; <\/p>\n<li><strong>The outlet temperatures of the water (inner hot fluid) dropped to around 46&deg;C, whereas in the experiment, it should be around 60&deg;C.<\/strong><\/li>\n<p>&lt;\/div&gt;&lt;div&gt;<\/ul>\n<p>&lt;\/div&gt;&lt;div&gt;&nbsp;&lt;\/div&gt;&lt;div&gt;&lt;p&gt;<strong>I am adding the details of this problem in the following section so that it&#8217;s easy to navigate the issue. I hope you will be kind enough to address this problem. :))<\/strong>&lt;\/p&gt;&lt;\/div&gt;&lt;p&gt;&nbsp;&lt;\/p&gt;&lt;p&gt;<img decoding=\"async\" src=\"https:\/\/innovationspace.ansys.com\/forum\/wp-content\/uploads\/sites\/2\/2024\/09\/01-09-2024-1725204531-temp_contour.jpg\" alt=\"\" \/>&lt;span style=&#8221;font-size: 14pt;&#8221;&gt;&lt;\/p&gt;&lt;p&gt;&lt;\/span&gt;<img decoding=\"async\" src=\"https:\/\/innovationspace.ansys.com\/forum\/wp-content\/uploads\/sites\/2\/2024\/09\/01-09-2024-1725204658-mceclip0.png\" \/>&lt;span style=&#8221;font-size: 14pt;&#8221;&gt;&lt;\/p&gt;&lt;p&gt;While defining the boundary condition, I found there were certain walls that were not visible to the actual geometry but they appeared in the boundary section. I cannot even display them with display geometry. I am not sure if they are influencing the results in any way.&lt;\/p&gt;&lt;p&gt;&lt;\/span&gt;<img decoding=\"async\" src=\"https:\/\/innovationspace.ansys.com\/forum\/wp-content\/uploads\/sites\/2\/2024\/09\/01-09-2024-1725204603-unknown_walls.png\" alt=\"\" \/>&lt;span style=&#8221;font-size: 14pt;&#8221;&gt;&lt;\/p&gt;&lt;p&gt;&nbsp;&lt;\/p&gt;&lt;p&gt;Furthermore, after initialising, in the console there was a warning that, there was a interface zone between the hot fluid(water) and cold fluid(air) . I am not entirely sure what it meant because, the fluid zones were defined correctly.&lt;\/p&gt;&lt;p&gt;I am adding my simulation setups, mesh and other images for the sake of describing this problem. &lt;\/span&gt;&lt;strong style=&#8221;font-size: 14pt;&#8221;&gt;Can you help me where things could have gone wrong and how will I be able to correct it?&nbsp;<\/strong>&lt;span style=&#8221;font-size: 14pt;&#8221;&gt;&lt;\/p&gt;&lt;p&gt;I have used Turbulent realizable K epsilon model with enhanced wall treatment.&lt;\/p&gt;&lt;p&gt;&lt;\/span&gt;<img decoding=\"async\" src=\"https:\/\/innovationspace.ansys.com\/forum\/wp-content\/uploads\/sites\/2\/2024\/09\/01-09-2024-1725204769-mceclip7.png\" \/>&lt;span style=&#8221;font-size: 14pt;&#8221;&gt;&lt;\/p&gt;&lt;p&gt;&nbsp;&lt;\/p&gt;&lt;p&gt;&nbsp;&lt;\/p&gt;&lt;p&gt;Turbulence contour:&lt;\/p&gt;&lt;p&gt;&lt;\/span&gt;<img decoding=\"async\" src=\"https:\/\/innovationspace.ansys.com\/forum\/wp-content\/uploads\/sites\/2\/2024\/09\/01-09-2024-1725204731-mceclip5.png\" \/>&lt;span style=&#8221;font-size: 14pt;&#8221;&gt;&lt;\/p&gt;&lt;p&gt;&nbsp;&lt;\/p&gt;&lt;p&gt;Residuals:&lt;\/p&gt;&lt;p&gt;&lt;\/span&gt;<img decoding=\"async\" src=\"https:\/\/innovationspace.ansys.com\/forum\/wp-content\/uploads\/sites\/2\/2024\/09\/01-09-2024-1725204783-mceclip8.png\" \/>&lt;span style=&#8221;font-size: 14pt;&#8221;&gt;&lt;\/p&gt;&lt;p&gt;&nbsp;&lt;\/p&gt;&lt;p&gt;unknown wall boundary conditions:&lt;\/p&gt;&lt;p&gt;&lt;\/span&gt;<img decoding=\"async\" src=\"https:\/\/innovationspace.ansys.com\/forum\/wp-content\/uploads\/sites\/2\/2024\/09\/01-09-2024-1725204817-mceclip10.png\" \/>&lt;span style=&#8221;font-size: 14pt;&#8221;&gt;&lt;\/p&gt;&lt;\/p&gt;&lt;p&gt;Geometry and mesh :&nbsp;&lt;\/p&gt;&lt;p&gt;&nbsp;&lt;\/p&gt;&lt;p&gt;&lt;\/span&gt;<img decoding=\"async\" src=\"https:\/\/innovationspace.ansys.com\/forum\/wp-content\/uploads\/sites\/2\/2024\/09\/01-09-2024-1725205115-mceclip0.png\" \/><img decoding=\"async\" src=\"https:\/\/innovationspace.ansys.com\/forum\/wp-content\/uploads\/sites\/2\/2024\/09\/01-09-2024-1725205115-mceclip1.png\" \/>&lt;span style=&#8221;font-size: 14pt;&#8221;&gt;&lt;\/p&gt;&lt;\/span&gt;&lt;\/p&gt;<\/p>\n","protected":false},"template":"","class_list":["post-381274","topic","type-topic","status-publish","hentry"],"aioseo_notices":[],"acf":[],"custom_fields":[{"0":{"_bbp_subscription":["440817","8124"],"_bbp_author_ip":["118.179.2.146"],"_btv_view_count":["271"],"_bbp_topic_status":["unanswered"],"_edit_last":["440817"],"_bbp_revision_log":["a:1:{i:381275;a:2:{s:6:\"author\";i:440817;s:6:\"reason\";s:0:\"\";}}"],"_bbp_topic_id":["381274"],"_bbp_forum_id":["27792"],"_bbp_engagement":["8124","440817"],"_bbp_voice_count":["2"],"_bbp_reply_count":["1"],"_bbp_last_reply_id":["381737"],"_bbp_last_active_id":["381737"],"_bbp_last_active_time":["2024-09-06 12:21:45"]},"test":"rakibul-buet19gmail-com"}],"_links":{"self":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/topics\/381274","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":1,"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/topics\/381274\/revisions"}],"predecessor-version":[{"id":381275,"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/topics\/381274\/revisions\/381275"}],"wp:attachment":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/media?parent=381274"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}