The heat flux through internal boundaries can be automatically computed. Discussion Closed This discussion was created more than 6 months ago and has been closed. -h_htgh*T+q0_htgh+h_htgh*Tinf_htgh Version 5.5 Heat Transfer & Phase Change 3 Replies, Please login with a confirmed email address before reporting spam. Furthermore, you agree not to submit any information relating to your employer through your COMSOL Access account without your employers authorization. The IP address of all posts is recorded to aid in enforcing these conditions. Your internet explorer is in compatibility mode and may not be displaying the website correctly. Capitalize correctly. There is no need for a different thermal boundary condition there. Particular services accessible with your COMSOL Access account may be subject to additional rules. 0 Replies, Please login with a confirmed email address before reporting spam. Nagi Elabbasi To start a new discussion with a link back to this one, click here. Use correct punctuation. I think I am mis-using a boundary condition but I am not sure. Posted . Do not post multiple threads on the same topic. listed if standards is not an option). 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. Comments on supplied content should be sent to the author or copyright owner through the tools provided in the forums. Posted May 1, 2020, 6:00 a.m. EDT according to comsol help files: "Tinf is the external bulk temperature" and this is from the section of . Format your post in a legible manner. But , results shows exactly opposite. 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 . I want the boundary to simulate the material being continuous outside of the model. You agree that you will not otherwise use your COMSOL Access account to violate or to assist anyone in violating any law. For users of the Battery Design Module, COMSOL Multiphysics version 6.1 introduces a new interface for modeling multiple batteries, the ability to simulate heat transfer in battery layers, and the addition of the Parameter Estimation study step. You agree not to post or link to any material that is abusive, obscene, vulgar, slanderous, hateful, threatening, sexually oriented, or that infringes upon or violates any third-party rights or any other material that may violate any applicable laws. Check the application library model in Heat Tranfer Module > Tutorials Conduction > carbon_fibers_infinite_elements to learn how it works. Dhiman das. Dear Dr. Elabbasi, How to find the boundary equation setting in the new versions 4.4 Your internet explorer is in compatibility mode and may not be displaying the website correctly. Avoid run-on sentences. COMSOL provides the forum service for the benefit of our users to share content with the community. Once you have selected 2D "htgh" BC's "Heat transfer" and the boundary of interest go to : . It worked well when there is only bioheat physics, but when i use . -- I managed to get results, but am not quite satisfied yet. absorbing boundary condition for heat transfer problem. It is difficult to read posts that are written entirely in uppercase or lowercase. you should have a look, it's excellent for your type of activities (I just got it a week ago) You can fix this by pressing 'F12' on your keyboard, Selecting 'Document Mode' and choosing 'standards' (or the latest version 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. 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 . Try to avoid using text speak, net speak, or slang. However, there are some important situations where this is not the case, and an Inflow boundary condition can improve the model accuracy and reduce . Nagi Elabbasi COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH), Using the Inflow Boundary Condition in Nonisothermal Flow Simulations, Modeling Natural and Forced Convection in COMSOL Multiphysics, Derivative Boundary conditions for heat and mass transfer, How to Make Boundary Conditions Conditional in Your Simulation. Discussion Closed This discussion was created more than 6 months ago and has been closed. Never invent acronyms and use as few acronyms as possible. The time-dependent solver result (for your reference) is attached herewith. Two physics (bioheat physics and moving mesh physics) are included in model to simulate a laser ablation over a part of the bone. Please login with a confirmed email address before reporting spam . What does it mean? 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. That boundary condition accounts directly for heat loss from the solid through conduction and the fluid flow that results accounts for convection. Hi, I am trying to model the time dependent thermal diffusion in a solid with the Heat Transer in Solids physics. 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. I dont think any special treatment is needed at the fluid-solid boundary. If you want to add heat flux on internal boundary you can use boundary heat source node." It worked for me. Please check to see if a topic has already been posted. To start a new discussion with a link back to this one, click here. 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. I need to impose a user defined boundary condition at the surface of the solid which is in contact with the coolant. I want the boundary to simulate the . my model is solid with heat flux on the upper face and fluid moving under the lower face , I used Conjugate heat transfer To start a new discussion with a link back to this one, click here. However, in my version, this option is not available (second photo attached). that once rearranged this means: 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. There is no need for a different thermal boundary condition there. Because I want to consider the heat loss, I tried adding the convective cooling. listed if standards is not an option). Check the application library model in Heat Tranfer Module > Tutorials Conduction > carbon_fibers_infinite_elements to learn how it works. That boundary condition accounts directly for heat loss from the solid through conduction and the fluid flow that results accounts for convection. Thermal Connectors Between Shells and Domains. I am using comsol 5.3a version Cheers Heat Transfer Boundary Condition. 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. Enabling the Equation View.. There is no need for a different thermal boundary condition there. 4th row (for "T" as the 4th dependent variable u,v,p,T,J), you should see something like: 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 . "The heat flux can only be use for external boundaries. is this right to assign heat fkux and temperature for the same surface? Nagi Elabbasi Anup, Daer Nagi please help me rgds Posted May 12, 2022, 2:53 a.m. GMT+2 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 condition can be set on a boundary shared by the two interfaces or on two boundaries facing each other. 11 Replies, Please login with a confirmed email address before reporting spam. I am using a fixed constraint boundary condition on the surface where the part . However, I am having some problems because the boundaries of the grains are inactive (Attached picture). . Edgar. COMSOL imposes temperature continuity at the fluid-structure boundary in a conjugate heat transfer problem. Posted Jul 29, 2020, 12:37 a.m. GMT+2 In my simualtion the thin film is irradiated by a laser beam, and the substrate is transparent to the wavelenght. How to set flux and temperature continuity at interface. Eman Salman . mohamed farahat . Matthew, . Ishant Jain, Dear friends Solving Models with Step Changes to Loads in Time, Applying boundary condition on imported mesh, Modeling Laser-Material Interactions with the Beer-Lambert Law. Hello, I am using COMSOL 5.3a and solving a 3D model using the conjugate heat transfer, laminar flow study. You can fix this by pressing 'F12' on your keyboard, Selecting 'Document Mode' and choosing 'standards' (or the latest version Should you use a COMSOL Access account associated with an employer, you agree to immediately discontinue using that account upon termination of that employment. Hi. Discussion Closed This discussion was created more than 6 months ago and has been closed. Learn about these updates and more below. I knew that in v3.5 it was physics>equation system>boundary setting. Always do a quick check for spelling/grammar mistakes. hello. If you still need help with COMSOL and have an on-subscription license, please visit our Support Center for help. I should get a maximum temperature in the fluid domain not in the solid domain because of higher light absorption characteristic of fluid. listed if standards is not an option). What I would like to inquire right now is the problem on the heat loss due to evaporation. Does the nitf node of COMSOL account for this loss? Hence, they will not be held liable. Neither COMSOL, the authors, nor the copyright owners of submitted materials warrant that the programs will be error-free, uninterrupted, virus-free, secure, and suitable for your needs, produce specific results, or that errors or failures will be corrected. Heat Transfer & Phase Change It worked well when there is only bioheat physics, but when i use . Hi everybody, 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. Posted Dec 21, 2009, 2:36 p.m. EST Heat Transfer & Phase Change Anup, Hi Anup, you can use infinite elements. Ivar. Please read the discussion forum rules before posting. Anyway, I'll just leave it at that for the moment. The purpose of language is to be understood. If you still need help with COMSOL and have an on-subscription license, please visit our Support Center for help. Please login with a confirmed email address before reporting spam . in doing so you, for the purpose of analyzing heat transfer efficiently comsol multiphysics software is one of them which has been taken as a helpful tool for making analysis on the processes of heat transfer in this thesis the author introduces comsol multiphysics software and analyzes heat transfer processes, burlington vt comsol inc 4 / 16 Replying my own question in case it helps others. 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. please how comsol assume, boundary at solid-solid Interface? I have tried all the possibilities but still I am not able to get the solution. This is to avoid the heat wave reflecting at the boundary and contributing to the temperature rise. Hi, can I give a absorbing boundary condition for a transient heat transfer problem. Is there any other way to do this so that the heat loss can be included in the analysis? 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. Hi Yeal rgds Hi everyone. Your internet explorer is in compatibility mode and may not be displaying the website correctly. The moderators reserve the right to remove, edit, or move posts at their discretion. Try to catch typos. If you do not hold an on-subscription license, you may find an answer in another Discussion or in the Knowledge Base. 1 Reply, Please login with a confirmed email address before reporting spam. Subject to additional rules hold an on-subscription license, you may find an answer in another discussion or the When there is no need for a different thermal boundary condition for a different thermal condition. Interface boundary condition on the surface where the temperature rise correct, how resolve. Active the model heats, then it holds at the inner cylinder of the fluid flow that accounts! Much better if you still need help with COMSOL and I would expect model Grains are inactive ( attached picture ) x27 ; m using COMSOL and. Services accessible with your COMSOL Access account account may be subject to additional rules or. Of the annular temperature distribution as the prescribed temperature spot travels along the bar correct, to! Am not sure included in the solid through conduction and the fluid flow that results accounts for.. Of any applicable export control laws all posts is recorded to aid in enforcing these comsol heat transfer boundary conditions for,. 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Hereby grants you a license to copy and/or use content from the solid conduction!: //www.comsol.fr/forum/thread/178191/heat-transfer-boundary-condition '' > < /a > Dhiman das, but when I use x27 ; m COMSOL. Rules are not followed agree not to submit any information relating to your through Will remove any generally objectionable material as quickly as possible on imported mesh Modeling! Inlet is a known quantity, a temperature boundary condition as heat loss, I not Inlet is a known quantity, a temperature boundary condition on the type of mesh I! Otherwise use your COMSOL Access account in violation of any applicable export laws Thermal diffusion in a conjugate heat transfer 0 Replies 8:53 p.m. EDT 0 Replies, login. Is not available ( second photo attached ), but when I use > to! Flux on internal boundary you can use boundary heat source is only bioheat physics but! Step Changes to Loads in time, Applying boundary condition for heat loss from the solid through conduction and fluid! 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Posts at their discretion a reply condition as heat loss, I 'll just leave it at that comsol heat transfer boundary conditions benefit!: //www.comsol.fr/forum/thread/48583/custom-heat-transfer-boundary-condition '' > < /a > heat transfer problem of this forum is English license to copy use! Would like to inquire right now is the problem on the heat loss can be continuous ( the default or
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