{"id":275256,"date":"2023-03-17T06:10:37","date_gmt":"2023-03-17T06:10:37","guid":{"rendered":"\/forum\/?post_type=topic&#038;p=275256"},"modified":"2023-03-17T06:10:37","modified_gmt":"2023-03-17T06:10:37","slug":"negative-total-pressure-in-pump-simulation","status":"closed","type":"topic","link":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/negative-total-pressure-in-pump-simulation\/","title":{"rendered":"Negative total pressure in pump simulation"},"content":{"rendered":"<p>I have a simulation for axial flow pump with the following details;<br \/>Inlet BC = Pressure (0.4 bar)<br \/>Outlet BC = massflow rate ( 6000 m3\/hr)<br \/>Ref. Pressure = 0 atm<br \/>Kw SST Turbulence model<br \/>Steady state simulation.<br \/>Y+ = ~2<\/p>\n<p>When I plot contours of total pressure, very large negative pressure values are observed ( in the orders of -500 KPa \/ -5.0 bar ).&nbsp;<br \/>How can this be possible when absolute pressure cannot be &lt; 0 in real world.<\/p>\n<p>We know, In Ansys, The total pressure is = static + dynamic&nbsp;<br \/>and Absolute pressure = Ref. operating pressure + static pressure<\/p>\n<p>&nbsp;<\/p>\n<p><img decoding=\"async\" src=\"\/forum\/wp-content\/uploads\/sites\/2\/2023\/03\/17-03-2023-1679031471-mceclip1.jpg\"><img loading=\"lazy\" decoding=\"async\" src=\"\/forum\/wp-content\/uploads\/sites\/2\/2023\/03\/17-03-2023-1679031477-mceclip2.jpg\" width=\"2622\" height=\"695\"><\/p>\n<ol>\n<li>In the Total Pressure contor, -ve pressure values are observed (at the impeller) which is expected as the impeller egde will have a lower pressure naturally.<\/li>\n<li>But looking at the second picture (i.e. Total pressure contour at Impeller blades), very large -ve pressures are observed which cannot be physically possible.&nbsp;<\/li>\n<li>What inference can i deduce from the above contours. (for e.g. cavitation? incorrect physics settings? numerical error?)<\/li>\n<\/ol>\n<p>Any comments \/ suggestions would be apperciated as it will help me make my case stronger.<br \/>Thank you<\/p>\n","protected":false},"template":"","class_list":["post-275256","topic","type-topic","status-closed","hentry","topic-tag-absolute-pressure-1","topic-tag-ansys-cfx","topic-tag-cavitation","topic-tag-incompressible-flow","topic-tag-pump","topic-tag-pump-impeller-1","topic-tag-steady-state","topic-tag-total-pressure"],"aioseo_notices":[],"acf":[],"custom_fields":[{"0":{"_bbp_author_ip":["23.192.164.14"],"_bbp_subscription":["126106","22555","199842"],"_btv_view_count":["2802"],"_bbp_topic_status":["unanswered"],"_bbp_status":["publish"],"_bbp_topic_id":["275256"],"_bbp_forum_id":["27792"],"_bbp_engagement":["22555","126106","199842"],"_bbp_voice_count":["3"],"_bbp_reply_count":["7"],"_bbp_last_reply_id":["275664"],"_bbp_last_active_id":["275664"],"_bbp_last_active_time":["2023-03-21 08:09:53"]},"test":"deepaktmtpl-com"}],"_links":{"self":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/topics\/275256","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\/275256\/revisions"}],"wp:attachment":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/media?parent=275256"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}