{"id":382639,"date":"2024-09-13T14:43:35","date_gmt":"2024-09-13T14:43:35","guid":{"rendered":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/how-to-setup-multiphase-mixture-simulating-incubation-of-agar\/"},"modified":"2024-09-13T14:43:35","modified_gmt":"2024-09-13T14:43:35","slug":"how-to-setup-multiphase-mixture-simulating-incubation-of-agar","status":"publish","type":"topic","link":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/how-to-setup-multiphase-mixture-simulating-incubation-of-agar\/","title":{"rendered":"How to setup multiphase mixture? (simulating incubation of agar)"},"content":{"rendered":"

<p>This is my first ansys simulation and I need some help. I am trying to simulate the incubation of agar and water used for microbiological testing of water. The agar-water mixture is put in a petri dish and left for 6 days to incubate at around 35 degrees Celsius. There are 6 petri dishes in total, stacked on top of each other. The petri dishes are also flipped in a way, that the agair-water mixture is on the top (the mixture is solid and does not fall down). After performing real life incubation tests, we noticed that condensation occurs in the petri dishes during incubation and water droplets form and fall down. Now, we want to simulate the incubation, to try and figure out how and why this condensation forms. <\/p><p>I have attached an image of the 2D geometry bellow. The gray square is used to model air, and the smaller green square is also air (the bigger square has larger elements, and the smaller square has smaller elements, which is important for the mesh).<\/p><p>\"\"<\/p><p>The next image shows the petri dishes closer. The petri dishes are put in a plastic box, with small gaps (2 mm) between each petri dish and between the bottom petri dish and the box.<\/p><p>\"\"<\/p><p>I want to simulate water evaporating from the agar-water mixture and condensating on the bottom of the petri dish. Our theory is that the agar-water mixture contributes to a 100% relative humidity inside the petri dishes. The upper part of one petri dish is colder than the bottom part of the petri dish above it. And it is this difference in temperature that causes a drop in temperature in the petri dish above, which results in condensation to form, since the relative humidity was at 100%. So we want to simulate this as closely as we can.<\/p><p>I completed the geometry and the mesh, and I have some questions about the setup:<\/p><\/p>\n

    \n
  1. I have activated Energy and chose Mixture for the Multiphase model. Are those all the models I need to activate?<\/li>\n
  2. This question is about the Multiphase model. I added the images with the setup. The Mixture Model has two phases, the first one is water-liquid (water) and the second is water-vapor (vapor). I added one Mass Transfer Interaction, which is evaporation-condensation. Is this the correct setup for the simulation I want to create?<\/li>\n<\/ol>\n

    <p>\"\"\"\"<\/p><p>\"\"<\/p><p>3. I want to model the agar-mixture as a solid with the properties of water. But the Mixture model only works with fluids as the phases. The only issue I have with this is that as a liquid, the water on the top of the petri dish will fall down, since gravity is turned on. Is there some way to make the water-liquid not fall down because of gravity or to use a solid as a phase in the Mixture model?<\/p><p>4. How do I set the agar as water-liquid in the beginning of the simulation? When I go to Cell Zone Conditions, I can assign materials to the solid zones, but I cannot assign materials to the fluids. Also, every zone (solids and fluids) are set to Phase: mixture. I change it to water (phase-1), but when I click on it again, it changes back to mixture. Is this ok?<\/p><p>5. I would also like to assign a certain temperature and relative humidity to the air, which slightly changes throughout the simulation (around 6 days). Those changes are +- 1 degree for the temperature and +-10% for the relative humidty. Does anyone know how to do this?<\/p><p>6. If there is anything else I missed and is important for the simulation, please tell me.<\/p><p>Thank you and best regards<\/p><\/p>\n","protected":false},"template":"","class_list":["post-382639","topic","type-topic","status-publish","hentry","topic-tag-fluent-ansys-1","topic-tag-fluent-cfd-ansys-1","topic-tag-fluent","topic-tag-fluent-mesh"],"aioseo_notices":[],"acf":[],"custom_fields":[{"0":{"_bbp_subscription":["303646","199"],"_bbp_author_ip":["193.2.84.130"],"_btv_view_count":["196"],"_bbp_topic_status":["unanswered"],"_bbp_topic_id":["382639"],"_bbp_forum_id":["27792"],"_bbp_engagement":["199","303646"],"_bbp_voice_count":["2"],"_bbp_reply_count":["5"],"_bbp_last_reply_id":["387653"],"_bbp_last_active_id":["387653"],"_bbp_last_active_time":["2024-10-01 12:28:53"]},"test":"pp2278student-uni-lj-si"}],"_links":{"self":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/topics\/382639","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\/382639\/revisions"}],"wp:attachment":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/media?parent=382639"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}