here<\/a>. One inlet is just water, the other one is a water-based ink solution (dilute, so that it basically does not change density and viscosity). Each inlet is at 0.5 m\/s. As this two fluids are miscible I believe “Species – Species Transport” model (and not any multiphase model) must be used, without reaction. Flow is laminar, steady state, and solution method is SIMPLE.<\/p>\nProblem 1:<\/strong> My expected result, from literature, logic and experiments is that unless the length of microchannel is very long there must be minimal mixing of the two streams (please see the figures I linked above), and that mostly due to diffusion. Their intrface must get blurry and we go downstream, but a complete mixing across the channel width will not occur. Well, in fact in microfluidics mixing is a challenge, because viscose forces dominate convective terms. However, in my simulation I see a very fast mixing (within few micrometers from the juction whole channel is uniformly mixed), which is totally non-physical. Decreasing Mass Diffusivity in mixture-template does not help, even if I do that by several orders of magnitude. <\/p>\nProblem 2:<\/strong> In using species transport I should define the mixture template; ideally a mixture of two water-based liquids. But his seems to be impossible. Once I add water-liquid (h2o<1>), Fluent wouldn’t let me add a second one into mixture template, saying h2o<l> is already there. So what I did was to use ethyl-alcohol-liquid (c2h5oh<l>) and change its accessible properties (density, viscosity,..) to that of water. Yet I am not sure this is the right approach. e.g., I don’t know if Fluent takes the chemical formula into account and does some additional calculations based on it… Also species model seems mostly orientated to solve combustion and reactive situations… I suspect (but am not sure) that this issue is the root cause for the first problem.<\/p>\nHow should I simulate this situation? Any help\/suggestion\/recommendation is much appreciated. <\/p>\n","protected":false},"template":"","class_list":["post-354040","topic","type-topic","status-closed","hentry"],"aioseo_notices":[],"acf":[],"custom_fields":[{"0":{"_bbp_subscription":["41157","199"],"_bbp_author_ip":["23.218.248.146"]," _bbp_last_reply_id":["0"]," _bbp_likes_count":["0"],"_btv_view_count":["1403"],"_bbp_topic_status":["unanswered"],"_bbp_topic_id":["354040"],"_bbp_forum_id":["27792"],"_bbp_engagement":["199","41157"],"_bbp_voice_count":["2"],"_bbp_reply_count":["7"],"_bbp_last_reply_id":["354571"],"_bbp_last_active_id":["354571"],"_bbp_last_active_time":["2024-02-29 14:51:30"],"_bbp_notification_enabled":["565535"]},"test":"9b644edcf22a607cafac5c4e1edaefc70158924b"}],"_links":{"self":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/topics\/354040","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\/354040\/revisions"}],"wp:attachment":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/media?parent=354040"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}