


{"id":462638,"date":"2026-08-14T14:28:26","date_gmt":"2026-08-14T14:28:26","guid":{"rendered":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/fluidised-bed-drying-simulation-tfm-eulerian-eulerian-model\/"},"modified":"2026-08-14T14:28:26","modified_gmt":"2026-08-14T14:28:26","slug":"fluidised-bed-drying-simulation-tfm-eulerian-eulerian-model","status":"publish","type":"topic","link":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/fluidised-bed-drying-simulation-tfm-eulerian-eulerian-model\/","title":{"rendered":"Fluidised Bed Drying Simulation, TFM &#8220;Eulerian-Eulerian&#8221; Model"},"content":{"rendered":"<p>Hi all,<\/p>\n<p>I&rsquo;m currently modelling a fluidised bed dryer in ANSYS Fluent using the Eulerian&ndash;Eulerian approach. I&rsquo;m using UDS to represent moisture in the gas and solid phases, with a UDF source term to transfer moisture from the solids into the gas.<\/p>\n<p>I&rsquo;m having trouble getting physically realistic mass transfer. At the moment, the predicted drying rate is extremely small, the solid moisture sometimes increases rather than decreases, and the mass transfer appears to occur only in small regions of the bed rather than throughout the solids. In some cases, the calculated drying driving force is negative across much of the domain.<\/p>\n<p>I&rsquo;ve been working through possible issues with the source-term sign, UDS boundary conditions, initialisation, saturation\/equilibrium moisture calculation, mass-transfer coefficient and how the gas and solid UDS equations are coupled.<\/p>\n<p>Has anyone implemented evaporation\/drying between Eulerian phases using UDS in Fluent before?<\/p>\n<p>I&rsquo;d mainly appreciate some guidance on <strong>where my overall mass-transfer implementation may be going wrong<\/strong>, or what checks you would recommend to determine whether the problem is coming from the UDF formulation, UDS setup, boundary conditions or the underlying drying model.<\/p>\n<p>Happy to share the UDF and Fluent setup if useful.<\/p>\n","protected":false},"template":"","class_list":["post-462638","topic","type-topic","status-publish","hentry","topic-tag-udf-2","topic-tag-fluent-1"],"aioseo_notices":[],"aioseo_head":"\n\t\t<!-- All in One SEO 4.9.10 - aioseo.com -->\n\t<meta name=\"description\" content=\"Hi all, I\u2019m currently modelling a fluidised bed dryer in ANSYS Fluent using the Eulerian\u2013Eulerian approach. I\u2019m using UDS to represent moisture in the gas and solid phases, with a UDF source term to transfer moisture from the solids into the gas. I\u2019m having trouble getting physically realistic mass transfer. At the moment, the predicted\" \/>\n\t<meta name=\"robots\" content=\"max-image-preview:large\" \/>\n\t<link rel=\"canonical\" href=\"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/fluidised-bed-drying-simulation-tfm-eulerian-eulerian-model\/\" \/>\n\t<meta name=\"generator\" content=\"All in One SEO (AIOSEO) 4.9.10\" \/>\n\t\t<meta property=\"og:locale\" content=\"en_US\" \/>\n\t\t<meta property=\"og:site_name\" content=\"Ansys Learning Forum | Ansys Innovation Space\" \/>\n\t\t<meta property=\"og:type\" content=\"article\" \/>\n\t\t<meta property=\"og:title\" content=\"Fluidised Bed Drying Simulation, TFM \u201cEulerian-Eulerian\u201d Model | Ansys Learning Forum\" \/>\n\t\t<meta property=\"og:description\" content=\"Hi all, I\u2019m currently modelling a fluidised bed dryer in ANSYS Fluent using the Eulerian\u2013Eulerian approach. I\u2019m using UDS to represent moisture in the gas and solid phases, with a UDF source term to transfer moisture from the solids into the gas. I\u2019m having trouble getting physically realistic mass transfer. At the moment, the predicted\" \/>\n\t\t<meta property=\"og:url\" content=\"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/fluidised-bed-drying-simulation-tfm-eulerian-eulerian-model\/\" \/>\n\t\t<meta property=\"article:published_time\" content=\"2026-08-14T14:28:26+00:00\" \/>\n\t\t<meta property=\"article:modified_time\" content=\"2026-08-14T14:28:26+00:00\" \/>\n\t\t<meta name=\"twitter:card\" content=\"summary_large_image\" \/>\n\t\t<meta name=\"twitter:title\" content=\"Fluidised Bed Drying Simulation, TFM \u201cEulerian-Eulerian\u201d Model | Ansys Learning Forum\" \/>\n\t\t<meta name=\"twitter:description\" content=\"Hi all, I\u2019m currently modelling a fluidised bed dryer in ANSYS Fluent using the Eulerian\u2013Eulerian approach. I\u2019m using UDS to represent moisture in the gas and solid phases, with a UDF source term to transfer moisture from the solids into the gas. I\u2019m having trouble getting physically realistic mass transfer. 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I\u2019m using UDS to represent moisture in the gas and solid phases, with a UDF source term to transfer moisture from the solids into the gas. I\u2019m having trouble getting physically realistic mass transfer. At the moment, the predicted","canonical_url":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/fluidised-bed-drying-simulation-tfm-eulerian-eulerian-model\/","robots":"max-image-preview:large","keywords":"","webmasterTools":{"miscellaneous":""},"schema":{"@context":"https:\/\/schema.org","@graph":[{"@type":"BreadcrumbList","@id":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/fluidised-bed-drying-simulation-tfm-eulerian-eulerian-model\/#breadcrumblist","itemListElement":[{"@type":"ListItem","@id":"https:\/\/innovationspace.ansys.com\/forum#listItem","position":1,"name":"Home","item":"https:\/\/innovationspace.ansys.com\/forum","nextItem":{"@type":"ListItem","@id":"https:\/\/innovationspace.ansys.com\/forum\/topics\/#listItem","name":"Topics"}},{"@type":"ListItem","@id":"https:\/\/innovationspace.ansys.com\/forum\/topics\/#listItem","position":2,"name":"Topics","item":"https:\/\/innovationspace.ansys.com\/forum\/topics\/","nextItem":{"@type":"ListItem","@id":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic-tag\/udf-2\/#listItem","name":"-UDF"},"previousItem":{"@type":"ListItem","@id":"https:\/\/innovationspace.ansys.com\/forum#listItem","name":"Home"}},{"@type":"ListItem","@id":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic-tag\/udf-2\/#listItem","position":3,"name":"-UDF","item":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic-tag\/udf-2\/","nextItem":{"@type":"ListItem","@id":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/fluidised-bed-drying-simulation-tfm-eulerian-eulerian-model\/#listItem","name":"Fluidised Bed Drying Simulation, TFM &#8220;Eulerian-Eulerian&#8221; Model"},"previousItem":{"@type":"ListItem","@id":"https:\/\/innovationspace.ansys.com\/forum\/topics\/#listItem","name":"Topics"}},{"@type":"ListItem","@id":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/fluidised-bed-drying-simulation-tfm-eulerian-eulerian-model\/#listItem","position":4,"name":"Fluidised Bed Drying Simulation, TFM &#8220;Eulerian-Eulerian&#8221; Model","previousItem":{"@type":"ListItem","@id":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic-tag\/udf-2\/#listItem","name":"-UDF"}}]},{"@type":"Organization","@id":"https:\/\/innovationspace.ansys.com\/forum\/#organization","name":"Ansys Learning Forum","description":"Ansys Innovation Space","url":"https:\/\/innovationspace.ansys.com\/forum\/"},{"@type":"WebPage","@id":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/fluidised-bed-drying-simulation-tfm-eulerian-eulerian-model\/#webpage","url":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/fluidised-bed-drying-simulation-tfm-eulerian-eulerian-model\/","name":"Fluidised Bed Drying Simulation, TFM \u201cEulerian-Eulerian\u201d Model | Ansys Learning Forum","description":"Hi all, I\u2019m currently modelling a fluidised bed dryer in ANSYS Fluent using the Eulerian\u2013Eulerian approach. I\u2019m using UDS to represent moisture in the gas and solid phases, with a UDF source term to transfer moisture from the solids into the gas. I\u2019m having trouble getting physically realistic mass transfer. At the moment, the predicted","inLanguage":"en-US","isPartOf":{"@id":"https:\/\/innovationspace.ansys.com\/forum\/#website"},"breadcrumb":{"@id":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/fluidised-bed-drying-simulation-tfm-eulerian-eulerian-model\/#breadcrumblist"},"datePublished":"2026-08-14T14:28:26+00:00","dateModified":"2026-08-14T14:28:26+00:00"},{"@type":"WebSite","@id":"https:\/\/innovationspace.ansys.com\/forum\/#website","url":"https:\/\/innovationspace.ansys.com\/forum\/","name":"Ansys Learning Forum","description":"Ansys Innovation Space","inLanguage":"en-US","publisher":{"@id":"https:\/\/innovationspace.ansys.com\/forum\/#organization"}}]},"og:locale":"en_US","og:site_name":"Ansys Learning Forum | Ansys Innovation Space","og:type":"article","og:title":"Fluidised Bed Drying Simulation, TFM \u201cEulerian-Eulerian\u201d Model | Ansys Learning Forum","og:description":"Hi all, I\u2019m currently modelling a fluidised bed dryer in ANSYS Fluent using the Eulerian\u2013Eulerian approach. I\u2019m using UDS to represent moisture in the gas and solid phases, with a UDF source term to transfer moisture from the solids into the gas. I\u2019m having trouble getting physically realistic mass transfer. At the moment, the predicted","og:url":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/fluidised-bed-drying-simulation-tfm-eulerian-eulerian-model\/","article:published_time":"2026-08-14T14:28:26+00:00","article:modified_time":"2026-08-14T14:28:26+00:00","twitter:card":"summary_large_image","twitter:title":"Fluidised Bed Drying Simulation, TFM \u201cEulerian-Eulerian\u201d Model | Ansys Learning Forum","twitter:description":"Hi all, I\u2019m currently modelling a fluidised bed dryer in ANSYS Fluent using the Eulerian\u2013Eulerian approach. I\u2019m using UDS to represent moisture in the gas and solid phases, with a UDF source term to transfer moisture from the solids into the gas. I\u2019m having trouble getting physically realistic mass transfer. At the moment, the predicted"},"aioseo_meta_data":[],"aioseo_breadcrumb":"<div class=\"aioseo-breadcrumbs\"><span class=\"aioseo-breadcrumb\">\n\t\t\t<a href=\"https:\/\/innovationspace.ansys.com\/forum\" title=\"Home\">Home<\/a>\n\t\t<\/span><span class=\"aioseo-breadcrumb-separator\">&raquo;<\/span><span class=\"aioseo-breadcrumb\">\n\t\t\t<a href=\"https:\/\/innovationspace.ansys.com\/forum\/topics\/\" title=\"Topics\">Topics<\/a>\n\t\t<\/span><span class=\"aioseo-breadcrumb-separator\">&raquo;<\/span><span class=\"aioseo-breadcrumb\">\n\t\t\t<a href=\"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic-tag\/udf-2\/\" title=\"-UDF\">-UDF<\/a>\n\t\t<\/span><span class=\"aioseo-breadcrumb-separator\">&raquo;<\/span><span class=\"aioseo-breadcrumb\">\n\t\t\tFluidised Bed Drying Simulation, TFM \u201cEulerian-Eulerian\u201d Model\n\t\t<\/span><\/div>","aioseo_breadcrumb_json":[{"label":"Home","link":"https:\/\/innovationspace.ansys.com\/forum"},{"label":"Topics","link":"https:\/\/innovationspace.ansys.com\/forum\/topics\/"},{"label":"-UDF","link":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic-tag\/udf-2\/"},{"label":"Fluidised Bed Drying Simulation, TFM &#8220;Eulerian-Eulerian&#8221; Model","link":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/fluidised-bed-drying-simulation-tfm-eulerian-eulerian-model\/"}],"acf":[],"custom_fields":[{"0":{"_bbp_forum_id":["27796"],"_bbp_topic_id":["462638"],"_bbp_subscription":["719699"],"_bbp_author_ip":[null],"_bbp_last_reply_id":["0"],"_bbp_last_active_id":["462638"],"_bbp_last_active_time":["2026-08-14 14:28:26"],"_bbp_reply_count":["0"],"_bbp_reply_count_hidden":["0"],"_bbp_engagement":["1"],"_bbp_likes_count":["0"],"_btv_view_count":["11"],"application":["FLUENT"],"emailnotification":[null],"_bbp_topic_status":["unanswered"]},"test":"20161987student-curtin-edu-au"}],"_links":{"self":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/topics\/462638","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\/462638\/revisions"}],"wp:attachment":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/media?parent=462638"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}