{"id":159299,"date":"2021-06-09T08:27:13","date_gmt":"2021-06-09T08:27:13","guid":{"rendered":"\/forum\/forums\/topic\/fluent-species-model-chemkin-mechanism\/"},"modified":"2021-06-14T16:47:55","modified_gmt":"2021-06-14T16:47:55","slug":"fluent-species-model-chemkin-mechanism","status":"closed","type":"topic","link":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/fluent-species-model-chemkin-mechanism\/","title":{"rendered":"[FLUENT] Species Model: CHEMKIN Mechanism"},"content":{"rendered":"<div class=\"Item-Body\">\n<div class=\"Message userContent\">\n<p>Dear all, <\/p>\n<p>I am trying to model a furnace where different reactants react with oxygen (combustion). The reactions are not at all complex. I am using a CHEMKIN mechanism:<\/p>\n<p>ELEMENTS C O S H N<\/p>\n<p>END<\/p>\n<p>SPECIES<\/p>\n<p>COS O2 CO2 SO2 H2S H2O C2H6S CO C4H8O S N2<\/p>\n<p>END<\/p>\n<p>REACTIONS<\/p>\n<p>COS+1.5O2=CO2+SO2 1E6 0&nbsp;&nbsp;&nbsp;0<\/p>\n<p>H2S+1.5O2=H2O+SO2 1E6 0&nbsp;&nbsp;&nbsp;0<\/p>\n<p>C2H6S+4.5O2=2CO2+3H2O+SO2 1E6 0&nbsp;&nbsp;&nbsp;0<\/p>\n<p>CO+0.5O2=CO2 1E6 0&nbsp;&nbsp;&nbsp;0<\/p>\n<p>C4H8O+5.5O2=4CO2+4H2O 1E6 0&nbsp;&nbsp;&nbsp;0<\/p>\n<p>S+O2=SO2 1E6 0&nbsp;&nbsp;&nbsp;0<\/p>\n<p>END<\/p>\n<p>Since I do not know the Ahrrenius coefficients for the kinetics, I decided to model the reactions as instantaneous and fast (0 activation energy and high value for A).<\/p>\n<p><\/p>\n<\/p>\n<p>The thermodynamic database is correct and constructed from the &quot;Third Millennium Ideal Gas and Condensed Phase Thermochemical Database for Combustion with Updates from Active Thermochemical Tables&quot; by Burcat and Ruscic.<\/p>\n<p><\/p>\n<\/p>\n<p>All the set-up is correct and as it should be. The simulation evolves correctly, no divergence at all and convergence of different controls such as mass conservation, energy etc. are also good. <\/p>\n<p><\/p>\n<\/p>\n<p>HOWEVER, the reaction involving C2H6S and C4H8O do not work. This is, they are not consumed at all. And yes, there is enough oxygen in the system. I don&#039;t understand why all the other 4 mechanisms do work and the reactants are correctly consumed (inexistent at the outlet) while for these two, I recover exactly the same ammount that I introduce into the system.<\/p>\n","protected":false},"template":"","class_list":["post-159299","topic","type-topic","status-closed","hentry","topic-tag-chemkin","topic-tag-fluent","topic-tag-fluids"],"aioseo_notices":[],"acf":[],"custom_fields":[{"0":{"_bbp_author_ip":[""],"_bbp_old_reply_author_name_id":["Anonymous"],"_bbp_old_is_reply_anonymous_id":["false"],"_btv_view_count":["916"],"_bbp_likes_count":["0"],"_bbp_subscription":["240724"],"_bbp_topic_status":["unanswered"],"_bbp_status":["publish"],"_bbp_topic_id":["159299"],"_bbp_forum_id":["27792"],"_bbp_engagement":["118","201608"],"_bbp_voice_count":["2"],"_bbp_reply_count":["4"],"_bbp_last_reply_id":["181525"],"_bbp_last_active_id":["181525"],"_bbp_last_active_time":["2021-06-14 16:47:55"]},"test":"deltaforcetrotgmail-com"}],"_links":{"self":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/topics\/159299","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\/159299\/revisions"}],"wp:attachment":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/media?parent=159299"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}