{"id":458114,"date":"2026-05-13T19:00:48","date_gmt":"2026-05-13T19:00:48","guid":{"rendered":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/why-does-the-entire-fluid-domain-attain-the-pressure-as-vaporization-pressure\/"},"modified":"2026-05-20T16:36:11","modified_gmt":"2026-05-20T16:36:11","slug":"why-does-the-entire-fluid-domain-attain-the-pressure-as-vaporization-pressure","status":"publish","type":"topic","link":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/why-does-the-entire-fluid-domain-attain-the-pressure-as-vaporization-pressure\/","title":{"rendered":"Why does the entire fluid domain attain the pressure as vaporization pressure?"},"content":{"rendered":"<p>&lt;p&gt;&lt;p&gt;&lt;p&gt;Dear Team,&lt;\/p&gt;&lt;p&gt;I am a research student and modelling a propellent flash-boiling flow inside a chamber of which only one side is open to atmosphere.&lt;\/p&gt;&lt;p&gt;I want to simulate the propellent is initially stored with a liquid volume fraction of propellent (at 6 bar), filling only 1\/3 rd part of the chamber. And rest 2\/3 rd part of the chamber contains vapour volume fraction of propellent (at 1 bar). To achieve that, I want to patch the liquid volume fraction with the vapour pressure of 6 bar and rest of the part with vapour volume fraction at atmospheric pressure of 1 bar.&lt;\/p&gt;&lt;p&gt; &lt;\/p&gt;&lt;p&gt;But after initialization, the entire chember attains the pressure equal to vapour pressure (i.e., 6 bar, an input value of caviation model for vapour pressure), and the Fluent does not allow to patch my desired 2\/3 rd part of the chamber at atmospheric pressure of 1 bar. But, Fluent does allow me to patch the desired volume fraction.&lt;\/p&gt;&lt;p&gt; &lt;\/p&gt;&lt;p&gt;Other Modelling Setup details as follows:&lt;\/p&gt;&lt;p&gt;Fluent Version &#8211; 2024R2 &lt;\/p&gt;&lt;p&gt;State &#8211; Transient&lt;\/p&gt;&lt;p&gt;Models &#8211; 3D, VOF, 2-Phase, Schnerr-Sauer caviation model.&lt;\/p&gt;&lt;p&gt;Turbulence Model &#8211; k-omega SST&lt;\/p&gt;&lt;p&gt;Mesh &#8211; Hexahedral &lt;\/p&gt;&lt;p&gt;Boundary conditions &#8211; Only Pressure Outlet with gauge pressure of 1 bar&lt;\/p&gt;&lt;p&gt;Material &#8211; Propellent liquid and Propellent vapour &lt;\/p&gt;&lt;\/p&gt;&lt;p&gt;Best Regards&lt;\/p&gt;&lt;\/p&gt;&lt;\/p&gt;<\/p>\n","protected":false},"template":"","class_list":["post-458114","topic","type-topic","status-publish","hentry","topic-tag-cavitation","topic-tag-fluent","topic-tag-ideal-gas","topic-tag-patch","topic-tag-transient"],"aioseo_notices":[],"acf":[],"custom_fields":[{"0":{"_bbp_forum_id":["27792"],"_bbp_topic_id":["458114"],"_bbp_subscription":["687234","199"],"_bbp_author_ip":["139.78.244.16"],"_bbp_last_reply_id":["458577"],"_bbp_last_active_id":["458577"],"_bbp_last_active_time":["2026-05-20 16:32:21"],"_bbp_reply_count":["14"],"_bbp_reply_count_hidden":["0"],"_bbp_voice_count":["2"],"_bbp_engagement":["687234","199"],"_btv_view_count":["99"],"_bbp_topic_status":["unanswered"],"_edit_last":["687234"],"_bbp_revision_log":["a:1:{i:458578;a:2:{s:6:\"author\";i:687234;s:6:\"reason\";s:0:\"\";}}"]},"test":"abhu123patilgmail-com"}],"_links":{"self":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/topics\/458114","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\/458114\/revisions"}],"predecessor-version":[{"id":458578,"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/topics\/458114\/revisions\/458578"}],"wp:attachment":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/media?parent=458114"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}