{"id":34524,"date":"2019-04-07T09:05:43","date_gmt":"2019-04-07T09:05:43","guid":{"rendered":"\/forum\/forums\/topic\/which-species-model-do-you-suggest\/"},"modified":"2019-04-07T09:05:43","modified_gmt":"2019-04-07T09:05:43","slug":"which-species-model-do-you-suggest","status":"closed","type":"topic","link":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/which-species-model-do-you-suggest\/","title":{"rendered":"which Species model do you suggest?"},"content":{"rendered":"

Hi All,<\/span><\/span><\/p>\n

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I’m using ANSYS fluent 19.1 to simulate a reactor in steady state condition with around 15 reactions in it. its a system of 15 reactions mechanism and I wrote a UDF (DEFINE_NET_REACTION_RATE…) for this purpose. the case is turbulent flow in a chamber with several tubes and I used realizable K-eps model for its hydrodynamics. the flow inside the chamber has two different behavior. there are some parts in the chamber that have very high velocity and high reaction rates (near some wall)  and some other parts with almost zero velocity but still high reaction rate! it should be noted that the flow behavior in the reactor is completely reasonable.<\/span><\/span><\/p>\n

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I chose volumetric reaction with Stiff Chemistry Solver and Finite-Rate\/No TCI <\/span> in my first try. it is working well at initial iteration but after that, as the reaction rate is high in some dead zones (with very low velocity), the Isat abort error also appeared that time. I’ve changed the under-relaxation factor and isat error tolerance but still have the same problem. it caused divergence and some defects in these zones. it is clear that the high reaction rate and stagnant flow in that area cause that problem. <\/span><\/span><\/p>\n

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\"\"<\/span><\/span><\/p>\n

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what’s your suggestion for my case?  is Finite-Rate\/No TCI<\/span> a good choice for me?<\/span><\/span><\/p>\n

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how can I get rid of this problem?<\/span><\/span><\/p>\n

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Many thanks for your consideration,<\/span><\/span><\/p>\n

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Morizio<\/span><\/p>\n","protected":false},"template":"","class_list":["post-34524","topic","type-topic","status-closed","hentry"],"aioseo_notices":[],"acf":[],"custom_fields":[{"0":{"_bbp_old_topic_id":["6696"],"_bbp_old_topic_author_name_id":["Anonymous"],"_bbp_old_is_topic_anonymous_id":["false"],"_bbp_old_closed_status_id":["publish"],"_bbp_author_ip":[null],"_bbp_old_sticky_status_id":["normal"],"_bbp_likes_count":["0","0"],"_btv_view_count":["1149"],"_bbp_topic_status":["unanswered"],"_bbp_status":["publish"],"_bbp_topic_id":["34524"],"_bbp_forum_id":["27792"],"_bbp_engagement":["199","22555","158946"],"_bbp_voice_count":["3"],"_bbp_reply_count":["11"],"_bbp_last_reply_id":["82906"],"_bbp_last_active_id":["82906"],"_bbp_last_active_time":["2019-04-14 16:22:33"]},"test":"morizio"}],"_links":{"self":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/topics\/34524","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\/34524\/revisions"}],"wp:attachment":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/media?parent=34524"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}