{"id":34928,"date":"2019-04-25T08:17:39","date_gmt":"2019-04-25T08:17:39","guid":{"rendered":"\/forum\/forums\/topic\/negative-pressure-by-using-compressible-liquid\/"},"modified":"2019-04-25T08:17:39","modified_gmt":"2019-04-25T08:17:39","slug":"negative-pressure-by-using-compressible-liquid","status":"closed","type":"topic","link":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/negative-pressure-by-using-compressible-liquid\/","title":{"rendered":"Negative Pressure by using compressible liquid"},"content":{"rendered":"

Hi everyone,<\/p>\n

<\/p>\n

By simulating the expansion of a compressible flow (using compressible liquid) in a chamber, negative static pressures and total pressures appear.<\/p>\n

<\/p>\n

For the initialisation I set a total pressure of 200 bar in the chamber and 10 bar before the porous media (models in green).<\/p>\n

<\/p>\n

The red line models a piston which moves downward. The boundary conditions are shown in the picture below:<\/p>\n

<\/p>\n

\"\"<\/p>\n

<\/p>\n

Problems are as follow:<\/p>\n

<\/p>\n

– By the expansion of the fluid, the temperature in the chamber should decrease (adiabatic walls). The problem is that the temperature remains constant for the whole geometry (before and after the porous media).<\/p>\n

<\/p>\n

– Negative static pressure appears by the downward motion of the piston when I plot the static pressure.<\/p>\n

<\/p>\n

 <\/p>\n

<\/p>\n

Settings: Fluent 19.2<\/p>\n

<\/p>\n

– Reliazable k-epsilon Model with Scalable Wall Function<\/p>\n

<\/p>\n

– Energy ON<\/p>\n

<\/p>\n

– Materials: Density using Compressible Liquid<\/p>\n

<\/p>\n

                   Thermal Conductivy as constant<\/p>\n

<\/p>\n

                   Viscosity as constant<\/p>\n

<\/p>\n

                   Heat Capacity using a polynomial function depending on temperature<\/p>\n

<\/p>\n

– Time Step 1E-5 s with 40 max. iter\/time step<\/p>\n

<\/p>\n

– Operatings Conditions: Pressure 101 325 Pa<\/p>\n

<\/p>\n

 <\/p>\n

<\/p>\n

Thank you in advance.<\/p>\n

<\/p>\n

Regards,<\/p>\n

<\/p>\n

Maxime<\/p>\n","protected":false},"template":"","class_list":["post-34928","topic","type-topic","status-closed","hentry"],"aioseo_notices":[],"acf":[],"custom_fields":[{"0":{"_bbp_old_topic_id":["7100"],"_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":["1499"],"_bbp_subscription":["237203"],"_bbp_topic_status":["unanswered"],"_bbp_status":["publish"],"_bbp_topic_id":["34928"],"_bbp_forum_id":["27792"],"_bbp_engagement":["199","22555","159144"],"_bbp_voice_count":["3"],"_bbp_reply_count":["15"],"_bbp_last_reply_id":["83888"],"_bbp_last_active_id":["83888"],"_bbp_last_active_time":["2019-04-26 14:30:05"]},"test":"max4"}],"_links":{"self":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/topics\/34928","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\/34928\/revisions"}],"wp:attachment":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/media?parent=34928"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}