{"id":319114,"date":"2023-11-23T00:41:25","date_gmt":"2023-11-23T00:41:25","guid":{"rendered":"\/forum\/forums\/topic\/inconsistent-results-in-vof-simulation-including-species-transport-equations\/"},"modified":"2023-11-23T00:41:25","modified_gmt":"2023-11-23T00:41:25","slug":"inconsistent-results-in-vof-simulation-including-species-transport-equations","status":"closed","type":"topic","link":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/inconsistent-results-in-vof-simulation-including-species-transport-equations\/","title":{"rendered":"Inconsistent results in VOF simulation including species transport equations"},"content":{"rendered":"<p>Hello!<\/p>\n<p>I am running a bubble column reactor.<\/p>\n<ul>\n<li>The column is filled with liquid metal. CH4 gas is injected from the nozzle which is submerged in the liquid metal, and is going to be bubbled. So, probably a VOF model is a good choice in this case.<\/li>\n<li>CH4 gas is decomposed by the reaction CH4(g) -&gt; 2H2(g) + C(s) in the liquid metal, because the liquid metal acts as a catalyst. So, without considering C(s) for the time being, CH4 and H2 (and other inert gases) can be treated as a gas mixture, constituting one &#8220;phase.&#8221;<\/li>\n<li>For the first simulation, I ignored chemical reactions and reaction products (H2, C(s)).&nbsp;<\/li>\n<\/ul>\n<p>So my setup is as follows:<\/p>\n<ul>\n<li>ANSYS Fluent 2020R1<\/li>\n<li>2D VOF simulation using two phases<\/li>\n<li>Primary phase: Liquid metal<\/li>\n<li>Secondary phase: Gas mixture (CH4, N2)<\/li>\n<\/ul>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"\/forum\/wp-content\/uploads\/sites\/2\/2023\/11\/23-11-2023-1700699041-vof1.png\" alt=\"\" width=\"733\" height=\"471\"><\/p>\n<p>This figure shows a contour of the volume fraction of phase-2 (gas mixture). The reactor is filled with liquid metal, N2 occupies over the free surface, and CH4 is injected from the submerged nozzle. Bubbling phenomenon is well captured.<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"\/forum\/wp-content\/uploads\/sites\/2\/2023\/11\/23-11-2023-1700699245-vof2.png\" alt=\"\" width=\"457\" height=\"463\"><\/p>\n<p>This figure shows a contour of the mass fraction of CH4 gas, which does not match with the contour of the volume fraction of phase-2.<\/p>\n<p>It looks like all the paths swept by CH4 is remained as CH4 region, even though the region was already covered by phase-1.<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"\/forum\/wp-content\/uploads\/sites\/2\/2023\/11\/23-11-2023-1700699664-vof3.png\" alt=\"\" width=\"594\" height=\"184\"><\/p>\n<p>However, Fluent Theory Guide says that when the species transport equation is solved with the multiphase flow model, the species mass fraction in the species transport equation is multiplied by the volume fraction of the phase. So, the mass fraction of CH4, which is a component of phase-2, should be zero at the cell occupied by phase-1.<\/p>\n<p>Am I missing some step?<\/p>\n<p>Thank you for your consideration.&nbsp;<\/p>\n","protected":false},"template":"","class_list":["post-319114","topic","type-topic","status-closed","hentry","topic-tag-multi-species-1","topic-tag-vof"],"aioseo_notices":[],"acf":[],"custom_fields":[{"0":{"_bbp_subscription":["302754","15180"],"_bbp_author_ip":["23.206.193.146"]," _bbp_last_reply_id":["0"]," _bbp_likes_count":["0"],"_btv_view_count":["1529"],"_bbp_topic_status":["unanswered"],"_bbp_status":["publish"],"_bbp_topic_id":["319114"],"_bbp_forum_id":["27792"],"_bbp_engagement":["15180","302754"],"_bbp_voice_count":["2"],"_bbp_reply_count":["2"],"_bbp_last_reply_id":["319898"],"_bbp_last_active_id":["319898"],"_bbp_last_active_time":["2023-11-29 04:44:29"]},"test":"sangwoo-kimkier-re-kr"}],"_links":{"self":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/topics\/319114","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\/319114\/revisions"}],"wp:attachment":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/media?parent=319114"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}