Note that while COMSOL employees may participate in the discussion forum, COMSOL software users who are on-subscription should submit their questions via the Support Center for a more comprehensive response from the Technical Support team. listed if standards is not an option). However, in my version, this option is not available (second photo attached). The goal of COMSOL Access is to provide a forum for you to communicate effectively with COMSOL as well as your colleagues within the multiphysics simulation community. Discussion Closed This discussion was created more than 6 months ago and has been closed. 1 Reply, Please login with a confirmed email address before reporting spam. you can use infinite elements. These rules are subject to change. -- Hence the Q variable (or q0_htgh internally) enters directly thermal power onto the boundary, while the "h" is proportional to the temperature difference (in K) of (Tinf-T) and T is the temperature you are solving for, so Tinf yould be your constant blood temperature, then h should be scaled to take into account . . Hi, can I give a absorbing boundary condition for a transient heat transfer problem. In order to make this an efficient and pleasant experience for you and other members of COMSOL Access, we ask that you follow a few rules and guidelines. rgds This periodicity can be continuous (the default) or anti-periodic and can control which of the dependent variables that the. Whilst the heat source is active the model heats, then it holds at the max temperature instead of dissipating the heat. That boundary condition accounts directly for heat loss from the solid through conduction and the fluid flow that results accounts for convection. Posted May 11, 2022, 8:53 p.m. EDT 0 Replies . You agree that you will not use your COMSOL Access account in violation of any applicable export control laws. In the tutorial (@ 11:49) the narrator assigns a "Surface-to-Ambient Radiation" boundary condition on the outer surface of the model (screen shot attached). Posted Jul 29, 2020, 12:37 a.m. GMT+2 How to find the boundary equation setting in the new versions 4.4 How to calculate the normal heat flux on a boundary - COMSOL I have tried all the possibilities but still I am not able to get the solution. It works well, except for the boundary conditions. Veryst Engineering Your Discussion has gone 30 days without a reply. Does the nitf node of COMSOL account for this loss? For example, you may have a tube in which the helium will flow through and inside that tube you will have your heated metal bar. However, in my problem the solid is under laser heating (consider as a volumetric heat generation based on Beer-Lambert law)in which i am defining optical properties for solid as well as for fluid such that fluid light absorption characteristic is greater than that of solid. Implementation of Periodic Boundary Condition | COMSOL - YouTube model heat convection between the tissue and blood I want to use on interior boundaries between the blood vessel the "heat flux discontinuity" boundary condition. App . Hi all Format your post in a legible manner. The IP address of all posts is recorded to aid in enforcing these conditions. Boundary condition for heat transfer. by the way you know about this book: http://www.comsol.com/academic/books/imtp/ You agree to comply with all rules applicable to each service you access through your COMSOL Access account. listed if standards is not an option). How to Make Boundary Conditions Conditional in Your Simulation - COMSOL Heat Transfer In my simualtion the thin film is irradiated by a laser beam, and the substrate is transparent to the wavelenght. COMSOL imposes temperature continuity at the fluid-structure boundary in a conjugate heat transfer problem. It is difficult to read posts that are written entirely in uppercase or lowercase. Engaging in any activity in violation of these COMSOL Access rules and guidelines may lead to you being immediately and permanently banned from COMSOL Access. Energies | Free Full-Text | The Forced Convection Analysis of Water Hence, they will not be held liable. You agree that you will not otherwise use your COMSOL Access account to violate or to assist anyone in violating any law. Modelling Heat Transfer from Fluid Channel in COMSOL? The passing of the heat air to the surface of the solid boundary caused heat and mass transfer at the same time resulting to some degree of heat loss. Hi Yeal Please login with a confirmed email address before reporting spam . you can use infinite elements. When registering for COMSOL Access, you agree to provide your complete and truthful information for all fields requested on your COMSOL Access account registration page. There is no need for a different thermal boundary condition there. "The heat flux can only be use for external boundaries. Ivar Kjelberg COMSOL Multiphysics(r) fan, "retired" but still part time CSEM SA (CH) Send . Good luck However, I am having some problems because the boundaries of the grains are inactive (Attached picture). I am using comsol 5.3a version I have tried the open boundary as well as symmetry conditions but in both cases there seems to be no conduction outside of the model. The simulation for the heat transfer is quiet good but the not in the mass transport. Hi. Send Private Message Flag post as spam. Nagi Elabbasi I need to impose a user defined boundary condition at the surface of the solid which is in contact with the coolant. Its fine that comsol itself taking care of interface boundary condition as heat loss from the solid. Nagi Elabbasi my model is solid with heat flux on the upper face and fluid moving under the lower face , I used Conjugate heat transfer Boundary condition for heat transfer - COMSOL Multiphysics We investigated the dynamics of nanofluid and heat transfer in a three-dimensional circular annular using the turbulence model and energy equations. It worked well when there is only bioheat physics, but when i use . Jonathan Perez. The time-dependent solver result (for your reference) is attached herewith. You represent and warrant that you are not subject to any comprehensive sanction or embargo by the U.S. or any other country, nor are you identified on any list maintained by the U.S. government that identifies persons for which the U.S. maintains restrictions. Try to catch typos. Please login with a confirmed email address before reporting spam . comsol heat transfer boundary conditions - Vibrantmotion much better if you upload your file for the other members to comment and have their suggestions. My model is similar to the tutorial here. Heat transfer in solids boundary conditions - comsol.fr Learn about these updates and more below. Use correct punctuation. In order to evaluate how to derive values in the Results section, I have followed the Heat sink tutorial included in COMSOL 4.2a and once I get the results of the simulation, I calculate the Surface Integration of the Total normal heat flux (nitf.ntflux) on surfaces 2, 3, 4 . All content is provided "as is" without warranty of any kind, express or implied, including without limitation, warranties of merchantability, noninfringement, design, operation, and fitness for a particular purpose, and the entire risk as to the quality and performance of the programs is with you. You acknowledge that all posts made to these forums express the views and opinions of the author and not the administrators, moderators, or webmaster (except for posts by these people). COMSOL imposes temperature continuity at the fluid-structure boundary in a conjugate heat transfer problem. Please read the discussion forum rules before posting. Modeling Heat Transfer with Comsol | Physics Forums What does it mean? Hence the Q variable (or q0_htgh internally) enters directly thermal power onto the boundary, while the "h" is proportional to the temperature difference (in K) of (Tinf-T) and T is the temperature you are solving for, so Tinf yould be your constant blood temperature, then h should be scaled to take into account the liquid solid exchange, but perhaps next step to take into account the blood flow, or total volume passing through, as the blood temperature might not manage to take/give all the heat, unaffected, if you have a sever feber, but I would propose not to use non-linear terms to start with. The data agrees with the Sherwood and Blasius correlations, however. You can fix this by pressing 'F12' on your keyboard, Selecting 'Document Mode' and choosing 'standards' (or the latest version Posted Dec 21, 2009, 2:36 p.m. EST The heat flux through internal boundaries can be automatically computed. Thanks. rgds You can fix this by pressing 'F12' on your keyboard, Selecting 'Document Mode' and choosing 'standards' (or the latest version Custom heat transfer boundary condition - comsol.fr hello. Here are some important guidelines of language: By submitting content to the forums, you hereby grant COMSOL a nonexclusive, royalty-free, perpetual, worldwide, and unrestricted license to reproduce, publicly display, publicly distribute, and prepare derivative works of the content. The Periodic Condition node adds a periodic boundary condition. listed if standards is not an option). [/QUOTE] Note that while COMSOL employees may participate in the discussion forum, COMSOL software users who are on-subscription should submit their questions via the Support Center for a more comprehensive response from the Technical Support team. Heat transfer in solids boundary conditions - COMSOL Multiphysics If you still need help with COMSOL and have an on-subscription license, please visit our Support Center for help. Anup, Hi Anup, I think I am mis-using a boundary condition but I am not sure. Heat Transfer & Phase Change To start a new discussion with a link back to this one, click here. There is no need for a different thermal boundary condition there. COMSOL imposes temperature continuity at the fluid-structure boundary in a conjugate heat transfer problem. Battery Design Module Updates - COMSOL 6.1 Release Highlights Posted May 12, 2022, 2:53 a.m. GMT+2 You just need to add the volumetric heat source to fluid and solid domains separately. Is there any other way to do this so that the heat loss can be included in the analysis? Am I doing it correctly? 0 Replies, Please login with a confirmed email address before reporting spam. 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