{"id":377312,"date":"2024-08-06T01:46:54","date_gmt":"2024-08-06T01:46:54","guid":{"rendered":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/dpm-particles-are-colliding-but-not-evaporating-in-combustion-model\/"},"modified":"2024-08-06T05:44:02","modified_gmt":"2024-08-06T05:44:02","slug":"dpm-particles-are-colliding-but-not-evaporating-in-combustion-model","status":"publish","type":"topic","link":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/dpm-particles-are-colliding-but-not-evaporating-in-combustion-model\/","title":{"rendered":"DPM particles are colliding but not evaporating in combustion model"},"content":{"rendered":"<p>Despite 3000k temps, my DPM particles are colliding, but barely evaporating causing a huge build up and causing the iterations to stall. Can they not evaporate after breakup? I also have an issue with the minimum temp being lower than the injected temp which in this case is obviously not possible. I have attached my full setup, and screenshots.<\/p>\n<p>General<\/p>\n<ul>\n<li>Pressure based, steady state, 3d<\/li>\n<\/ul>\n<p>Models<\/p>\n<ul>\n<li>Energy equation on<\/li>\n<li>k-e realizable turbulence model<\/li>\n<li>Species transport, 66 step, 31 species chemkin file for ethanol reaction and thermo properties (it is using units CAL\/MOL. Do I need manual unit conversion?)&nbsp;\n<ul>\n<li>eddy dissipation, relax to chemical equilibrium<\/li>\n<\/ul>\n<\/li>\n<li>DPM settings\n<ul>\n<li>Interact with continous phase on<\/li>\n<li>unsteady particle tracking on<\/li>\n<li>update dpm sources every flow iteration on, iterations set to 1<\/li>\n<li>Max number of tracking steps set to 50,000<\/li>\n<li>particle time step set to 1e-6<\/li>\n<li>stochastic collision, breakup, volume displacement, two-way turbulence coupling on<\/li>\n<\/ul>\n<\/li>\n<li>DPM injections, some of which are angled to impinge (start time 0, stop time 999999999). All positioned -.0001 below surface in order to make sure all particles end up in domain&nbsp;\n<ul>\n<li>25 multicomponent plain oriface atomizers with 10 steams&nbsp;\n<ul>\n<li>75% c2h5oh<\/li>\n<li>25% h2o<\/li>\n<li>Temp=400k<\/li>\n<li>location, diameter, length, mass flow rate taken from real injector<\/li>\n<li>vapor pressure 50 psi<\/li>\n<li>A=4.9, radius of curvature=1e-5, 0-360 angle (all left unchanged)<\/li>\n<\/ul>\n<\/li>\n<li>16 droplet plain oriface atomizer with 10 streams\n<ul>\n<li>100% Lox<\/li>\n<li>Temp=90k<\/li>\n<li>location, diameter, length, mass flow rate taken from real injector<\/li>\n<li>vapor pressure is 14psi<\/li>\n<li>A=4.9, radius of curvature=1e-5, 0-360 angle (all left unchanged)<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<\/li>\n<li>Chemkin mechanism mixture set to ideal gas in order to model compressible flow<\/li>\n<li>Boundary conditions\n<ul>\n<li>No inlets (all material injected using DPM)<\/li>\n<li>Pressure outlet set to no backflow, DPM escape<\/li>\n<li>Wall set to trap to help particles evaporate<\/li>\n<\/ul>\n<\/li>\n<li>Initialized at 300 psi expected operating pressure<\/li>\n<li>Patched chamber to 2500k for ignition<\/li>\n<\/ul>\n<p>&nbsp;<\/p>\n<p>As I mentioned, the particles seem to build instead of evaporating. In this photo you can see there is 74 million particles, despite having a simple geometry with only 570 total streams<a class=\"wp-colorbox-image cboxElement\" href=\"https:\/\/innovationspace.ansys.com\/forum\/wp-content\/uploads\/sites\/2\/2024\/08\/06-08-2024-1722907565-Screenshot 2024-08-05 181026.png\"><img decoding=\"async\" src=\"https:\/\/innovationspace.ansys.com\/forum\/wp-content\/uploads\/sites\/2\/2024\/08\/06-08-2024-1722907565-Screenshot 2024-08-05 181026.png\" alt=\"\"><\/a><\/p>\n<p>&nbsp;<\/p>\n<p><a class=\"wp-colorbox-image cboxElement\" href=\"https:\/\/innovationspace.ansys.com\/forum\/wp-content\/uploads\/sites\/2\/2024\/08\/06-08-2024-1722908660-Screenshot 2024-08-05 184406.png\"><img decoding=\"async\" src=\"https:\/\/innovationspace.ansys.com\/forum\/wp-content\/uploads\/sites\/2\/2024\/08\/06-08-2024-1722908660-Screenshot 2024-08-05 184406.png\" alt=\"\"><\/a><\/p>\n<p>&nbsp;<\/p>\n","protected":false},"template":"","class_list":["post-377312","topic","type-topic","status-publish","hentry","topic-tag-cfd-combustion","topic-tag-dpm"],"aioseo_notices":[],"acf":[],"custom_fields":[{"0":{"_bbp_subscription":["343144","199"],"_bbp_author_ip":["2601:601:8100:11e0:cc2e:4dee:92c8:30bb"]," _bbp_last_reply_id":["0"]," _bbp_likes_count":["0"],"_btv_view_count":["557"],"_bbp_topic_status":["unanswered"],"_edit_lock":["1722923044:343144"],"_bbp_topic_id":["377312"],"_bbp_forum_id":["27792"],"_bbp_engagement":["199","343144"],"_bbp_voice_count":["2"],"_bbp_reply_count":["10"],"_bbp_last_reply_id":["377735"],"_bbp_last_active_id":["377735"],"_bbp_last_active_time":["2024-08-08 15:50:48"]},"test":"zwernjaydengmail-com"}],"_links":{"self":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/topics\/377312","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":3,"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/topics\/377312\/revisions"}],"predecessor-version":[{"id":377327,"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/topics\/377312\/revisions\/377327"}],"wp:attachment":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/media?parent=377312"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}