{"id":41456,"date":"2020-03-04T00:22:14","date_gmt":"2020-03-04T00:22:14","guid":{"rendered":"\/forum\/forums\/topic\/phase-change-of-paraffin-wax\/"},"modified":"2020-03-04T00:22:14","modified_gmt":"2020-03-04T00:22:14","slug":"phase-change-of-paraffin-wax","status":"closed","type":"topic","link":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/phase-change-of-paraffin-wax\/","title":{"rendered":"Phase change of paraffin wax"},"content":{"rendered":"<p>Hello everyone !<\/p>\n<p><\/p>\n<p>I am working on the simulation of the melting of a phase change material, a paraffin wax named RT40. I want to visualize the phase change on a time-temperature diagram with ANSYS-FLUENT.<\/p>\n<p><\/p>\n<p>Initialy the RT40 is set to 293 K, the cylinder to 323 K. (Phase change is around 311 and 316 K)<\/p>\n<p><\/p>\n<p>I created on ANSYS-ICEM a cylinder closed on both side as the picture below :<img decoding=\"async\" src=\"https:\/\/us.v-cdn.net\/6032193\/uploads\/attachments\/49dad9a4-cd60-41b8-b6f6-ab7301827240\/cc604530-7a3a-4ee9-b9bf-ab7301868831_capture1.jpg?width=690&amp;upscale=false\" alt=\"Cylinder created on ICEM\"><\/p>\n<p><\/p>\n<p>As far as i know my mesh is fine, my criteria were :<\/p>\n<p><\/p>\n<ul><\/p>\n<li>Angle &gt; 18 &deg;<\/li>\n<p><\/p>\n<li>Quality &gt; 0.3<\/li>\n<p><\/p>\n<li>Aspect Ratio &lt;1000<\/li>\n<p><\/p>\n<li>Determinant &gt;0.3<\/li>\n<p><\/p>\n<li>Volume change &lt;10<\/li>\n<p><\/p>\n<li>Erikson skewness &gt;0.8<\/li>\n<p>\n<\/ul>\n<p><\/p>\n<p>Tell me if something is wrong with these criteria.<\/p>\n<p><\/p>\n<p>On Ansys-Fluent, i turned on the &#8220;energy&#8221; model and the &#8220;solidification and melting&#8221; model.<\/p>\n<p><\/p>\n<p>I created a material named rt40 with the following properties :<\/p>\n<p><\/p>\n<p><img decoding=\"async\" src=\"https:\/\/us.v-cdn.net\/6032193\/uploads\/attachments\/49dad9a4-cd60-41b8-b6f6-ab7301827240\/33a2a065-144d-4271-9bb7-ab73018b61f9_capture2.jpg?width=690&amp;upscale=false\" alt=\"\"><\/p>\n<p><\/p>\n<p>For the density, the specific heat capacity and the thermal conductivity i choose a piecewise-linear model with 4 points (273 &#8211; 311 &#8211; 316 &#8211; 373 K for the temperature) :<\/p>\n<p><\/p>\n<p><img decoding=\"async\" src=\"https:\/\/us.v-cdn.net\/6032193\/uploads\/attachments\/49dad9a4-cd60-41b8-b6f6-ab7301827240\/a9476a14-2003-4f67-b54e-ab7400004d8e_capture3.jpg?width=690&amp;upscale=false\" alt=\"\"><\/p>\n<p><\/p>\n<p>I fixed the temperature value of the cylinder to 323 K :<\/p>\n<p><\/p>\n<p><img decoding=\"async\" src=\"https:\/\/us.v-cdn.net\/6032193\/uploads\/attachments\/49dad9a4-cd60-41b8-b6f6-ab7301827240\/118c83e7-b1e9-46c5-bc10-ab7400015645_capture4.jpg?width=690&amp;upscale=false\" alt=\"\"><\/p>\n<p><\/p>\n<p>For boundaries between PCM and the cylinder, &#8220;coupled&#8221; was chosen : (The picture only show the bottom boundary)<\/p>\n<p><\/p>\n<p><img decoding=\"async\" src=\"https:\/\/us.v-cdn.net\/6032193\/uploads\/attachments\/49dad9a4-cd60-41b8-b6f6-ab7301827240\/ed3c2f2a-c341-4510-99ff-ab740002866f_capture5.jpg?width=690&amp;upscale=false\" alt=\"\"><\/p>\n<p><\/p>\n<p>For boundaries between the cylinder and the exterior, i just made them adiabatic :<\/p>\n<p><\/p>\n<p><img decoding=\"async\" src=\"https:\/\/us.v-cdn.net\/6032193\/uploads\/attachments\/49dad9a4-cd60-41b8-b6f6-ab7301827240\/17ae4685-f804-45b9-a4c0-ab7400031861_capture6.jpg?width=690&amp;upscale=false\" alt=\"\"><\/p>\n<p><\/p>\n<p>The following pictures shows the methods and controls used :<\/p>\n<p><\/p>\n<p><img decoding=\"async\" src=\"https:\/\/us.v-cdn.net\/6032193\/uploads\/attachments\/49dad9a4-cd60-41b8-b6f6-ab7301827240\/84b7e6ce-d070-43c9-b0d4-ab740003c63e_capture7.jpg?width=690&amp;upscale=false\" alt=\"\"><img decoding=\"async\" src=\"https:\/\/us.v-cdn.net\/6032193\/uploads\/attachments\/49dad9a4-cd60-41b8-b6f6-ab7301827240\/8692fd6c-f2e0-4967-ae0f-ab740003cd00_capture8.jpg?width=690&amp;upscale=false\" alt=\"\"><\/p>\n<p><\/p>\n<p>Then i initialized and patched the PCM zone to 293 K , the cylinder zone to 323 K.<\/p>\n<p><\/p>\n<p>I created 3 points in the center of the cylinder to visualize when my melting is over and the phase change plateau.<\/p>\n<p><\/p>\n<p>The following picture shows my parameters for the calculation :<\/p>\n<p><\/p>\n<p><img decoding=\"async\" src=\"https:\/\/us.v-cdn.net\/6032193\/uploads\/attachments\/49dad9a4-cd60-41b8-b6f6-ab7301827240\/13254209-4b56-41ad-8bb8-ab740004c443_capture9.jpg?width=690&amp;upscale=false\" alt=\"\"><\/p>\n<p><\/p>\n<p>The residuals are set to 1e-6, i choose 1000 for &#8220;Max iterations\/Time set&#8221; to ensure that the beginning of the calculation converge.<\/p>\n<p><\/p>\n<p>Now my problem is this :<\/p>\n<p><\/p>\n<p><img decoding=\"async\" src=\"https:\/\/us.v-cdn.net\/6032193\/uploads\/attachments\/49dad9a4-cd60-41b8-b6f6-ab7301827240\/a96f439c-ba78-4531-931f-ab740005aefb_capture10.jpg?width=690&amp;upscale=false\" alt=\"\"><\/p>\n<p><\/p>\n<p>This is a plot of the temperature of a point in the middle of the cylinder. But we can&#8217;t see a plateau where the phase change appears.<\/p>\n<p><\/p>\n<p>Where is\/are my errors ?<\/p>\n<p><\/p>\n<p>&nbsp;<\/p>\n<p><\/p>\n<p>Best regards<\/p>\n","protected":false},"template":"","class_list":["post-41456","topic","type-topic","status-closed","hentry"],"aioseo_notices":[],"acf":[],"custom_fields":[{"0":{"_bbp_old_topic_id":["13636"],"_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"],"_btv_view_count":["2171"],"_bbp_subscription":["248196"],"_bbp_topic_status":["unanswered"],"_bbp_status":["publish"],"_bbp_topic_id":["41456"],"_bbp_forum_id":["27792"],"_bbp_engagement":["199","173971"],"_bbp_voice_count":["2"],"_bbp_reply_count":["2"],"_bbp_last_reply_id":["106937"],"_bbp_last_active_id":["106937"],"_bbp_last_active_time":["2020-03-04 16:20:48"]},"test":"rugaard"}],"_links":{"self":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/topics\/41456","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\/41456\/revisions"}],"wp:attachment":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/media?parent=41456"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}