{"id":373516,"date":"2024-07-25T03:05:48","date_gmt":"2024-07-25T03:05:48","guid":{"rendered":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/volume-fraction-too-low-how-to-improve\/"},"modified":"2024-07-25T03:05:48","modified_gmt":"2024-07-25T03:05:48","slug":"volume-fraction-too-low-how-to-improve","status":"closed","type":"topic","link":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/volume-fraction-too-low-how-to-improve\/","title":{"rendered":"Volume Fraction too Low. How to Improve?"},"content":{"rendered":"<p>Hi, I am trying to simulate Multiphase condensation on a single tube. Below is my geometry image.<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/innovationspace.ansys.com\/forum\/wp-content\/uploads\/sites\/2\/2024\/07\/25-07-2024-1721874897-mceclip0.png\" width=\"359\" height=\"404\"><\/p>\n<p>I use Multiphase &gt; VOF &gt; Implicit &gt; Sharp &gt; Evaporation&mdash;condensation at 300K with 500 condensation frequency as a condensation model with transient flow. The gravity is -9.81.<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/innovationspace.ansys.com\/forum\/wp-content\/uploads\/sites\/2\/2024\/07\/25-07-2024-1721875234-mceclip1.png\" width=\"699\" height=\"404\"><\/p>\n<p>Tube wall temperature is 273.15K from Cell Zone &gt; fixed values.&nbsp;<\/p>\n<p>Inlet = mass flow rate of Vapor Ammonia is 0.00414282Kg\/s with a temperature of 300K and a pressure of 1061700Pa.<\/p>\n<p>Outlet = backflow temp = 297K with Backflow VF = 1. Pressure = 968150Pa.<\/p>\n<p>The pressure, thermal conductivity, etc., are taken from REFPROP at saturation temperature.&nbsp;<\/p>\n<p>Hybrid initialization with an initial patch of vapor in the whole domain.&nbsp;<\/p>\n<p>I have done many variations but the volume fraction I am getting is very very low . how can I improve the volume fraction?<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/innovationspace.ansys.com\/forum\/wp-content\/uploads\/sites\/2\/2024\/07\/25-07-2024-1721876298-mceclip2.jpg\" width=\"653\" height=\"358\"><\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/innovationspace.ansys.com\/forum\/wp-content\/uploads\/sites\/2\/2024\/07\/25-07-2024-1721876317-mceclip3.jpg\" width=\"630\" height=\"346\"><\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/innovationspace.ansys.com\/forum\/wp-content\/uploads\/sites\/2\/2024\/07\/25-07-2024-1721876340-mceclip4.jpg\" width=\"627\" height=\"345\"><\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/innovationspace.ansys.com\/forum\/wp-content\/uploads\/sites\/2\/2024\/07\/25-07-2024-1721876365-mceclip5.jpg\" width=\"627\" height=\"345\"><\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/innovationspace.ansys.com\/forum\/wp-content\/uploads\/sites\/2\/2024\/07\/25-07-2024-1721876549-mceclip6.jpg\" width=\"634\" height=\"314\"><\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/innovationspace.ansys.com\/forum\/wp-content\/uploads\/sites\/2\/2024\/07\/25-07-2024-1721876575-mceclip7.jpg\" width=\"639\" height=\"307\"><\/p>\n<p>I have share residuals, mass flow rate (in\/out), vapor in domain(100%), Liquid out (0%), heat fluxes. what do I need to share more?<\/p>\n","protected":false},"template":"","class_list":["post-373516","topic","type-topic","status-closed","hentry","topic-tag-multiphase_models-1","topic-tag-multiphaseudfevaporationdpmspeciestransportdefinesourcesourcetermeulerianlagrangian-1","topic-tag-condensation-evaporation-1","topic-tag-ImplicitVOF-1","topic-tag-multifluid-vof-1"],"aioseo_notices":[],"acf":[],"custom_fields":[{"0":{"_bbp_subscription":["294380","199"],"_bbp_author_ip":["124.16.3.16"]," _bbp_last_reply_id":["0"],"_btv_view_count":["1708"]," _bbp_likes_count":["0"],"_bbp_topic_status":["unanswered"],"_bbp_notification_enabled":["294380"],"_bbp_topic_id":["373516"],"_bbp_forum_id":["27792"],"_bbp_engagement":["199","294380"],"_bbp_voice_count":["2"],"_bbp_reply_count":["34"],"_bbp_last_reply_id":["379610"],"_bbp_last_active_id":["379610"],"_bbp_last_active_time":["2024-08-21 08:35:26"]},"test":"abdullahhassanmail-ustc-edu-cn"}],"_links":{"self":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/topics\/373516","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\/373516\/revisions"}],"wp:attachment":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/media?parent=373516"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}