Heat Transfer & Phase Change That boundary condition accounts directly for heat loss from the solid through conduction and the fluid flow that results accounts for convection. Animation of the temperature distribution as the prescribed temperature spot travels along the bar. 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). Should you use a COMSOL Access account associated with an employer, you agree to immediately discontinue using that account upon termination of that employment. The simulation for the heat transfer is quiet good but the not in the mass transport. and take alook at i.e. much better if you upload your file for the other members to comment and have their suggestions. 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. -h_htgh*T+q0_htgh+h_htgh*Tinf_htgh Never invent acronyms and use as few acronyms as possible. Posted 21.12.2009, . Your Discussion has gone 30 days without a reply. If you do not hold an on-subscription license, you may find an answer in another Discussion or in the Knowledge Base. The heat source is only active initially, and I would expect the model to reach thermal equilibrium with the surroundings/boundary conditions. Your Discussion has gone 30 days without a reply. If you still need help with COMSOL and have an on-subscription license, please visit our Support Center for help. You agree to maintain your COMSOL Access account for use solely by you, not to share your username and password with anyone else, and to take appropriate precautions to restrict access to your username and password from others. Anyway, I'll just leave it at that for the moment. Physics - Equation Systems - Boundary Settings You just need to add the volumetric heat source to fluid and solid domains separately. please help in this regard. Now to understand how COMSOL isusing these and how they are related (Tinf is only linked to "h") take a look at the equations: Jonathan Perez. Heat Transfer & Phase Change Discussion Closed This discussion was created more than 6 months ago and has been closed. I have tried all the possibilities but still I am not able to get the solution. Anup, Hi Anup, In order to understand how this works, enable the Equation View, and look at the implementation of the Dirichlet condition (in this case, a prescribed temperature):. Use correct punctuation. Your internet explorer is in compatibility mode and may not be displaying the website correctly. The constraint is formulated as ht.T0-ht.Tvar, which . Is there a way to go about this? However, in my version, this option is . Discussion Closed This discussion was created more than 6 months ago and has been closed. I'm using COMSOL 5.3 to simulate laminar flow in a microchannel that has few internal closed features inside. 0 Replies, Please login with a confirmed email address before reporting spam, Dear all Review your post before publishing it. Discussion Closed This discussion was created more than 6 months ago and has been closed. Thanks. 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 h_htgh* (Tinf_htgh-T) + q0_htgh. COMSOL provides the forum service for the benefit of our users to share content with the community. listed if standards is not an option). We investigated the dynamics of nanofluid and heat transfer in a three-dimensional circular annular using the turbulence model and energy equations. mohamed farahat . Coupling Heat transfer in solids with heat transfer in a porous medium (geothermal application), Manually Setting the Scaling of Variables, Guidelines for Equation-Based Modeling in Axisymmetric Components, Enclosed Geometry Heat Transfer in Solids. I am using a fixed constraint boundary condition on the surface where the part . The pipe contained two concentric and rotating cylinders with a constant speed in the tangential direction. Once you have selected 2D "htgh" BC's "Heat transfer" and the boundary of interest go to : 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. "The heat flux can only be use for external boundaries. My model is similar to the tutorial here. Hi!! 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. Your internet explorer is in compatibility mode and may not be displaying the website correctly. COMSOL imposes temperature continuity at the fluid-structure boundary in a conjugate heat transfer problem. COMSOL hereby grants you a license to copy and/or use content from the forums solely for your own internal purposes. 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. 3 Replies, Please login with a confirmed email address before reporting spam. I want the boundary to simulate the material being continuous outside of the model. Two physics (bioheat physics and moving mesh physics) are included in model to simulate a laser ablation over a part of the bone. comsol heat transfer boundary conditions. Your internet explorer is in compatibility mode and may not be displaying the website correctly. Your internet explorer is in compatibility mode and may not be displaying the website correctly. Two physics (bioheat physics and moving mesh physics) are included in model to simulate a laser ablation over a part of the bone. You can fix this by pressing 'F12' on your keyboard, Selecting 'Document Mode' and choosing 'standards' (or the latest version [/QUOTE] 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. I am trying to simulate the behaviour of optics components when being cooled down from 293K to 4K.I am using Solid Mechanics and Heat Transfer to Solids, where i am applying they temperature to all boundaries. You might have found out by now, I hope so, but in anycase, in the boundary condition Heat flux you have 2 variables Q and h, you might either choose one or the other, or both. Edgar. When posting, understand that you are trying to communicate with other people. Its fine that comsol itself taking care of interface boundary condition as heat loss from the solid. anup, [QUOTE] Try to catch typos. 0 Replies, Please login with a confirmed email address before reporting spam. This involves providing you with access to technical support and downloads of the latest {:comsol} software releases, as well as the ability to share your comments and work with other users of the {:comsol} software through forums such as the blog, discussion forum, and Application Exchange. . rgds Veryst Engineering Your internet explorer is in compatibility mode and may not be displaying the website correctly. 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. 11 Replies, Please login with a confirmed email address before reporting spam. 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. Now under step size, some times it appears "out" and sometimes different values. You can fix this by pressing 'F12' on your keyboard, Selecting 'Document Mode' and choosing 'standards' (or the latest version In my simualtion the thin film is irradiated by a laser beam, and the substrate is transparent to the wavelenght. Check the application library model in Heat Tranfer Module > Tutorials Conduction > carbon_fibers_infinite_elements to learn how it works. March 15, 2018. Hi everyone. listed if standards is not an option). COMSOL imposes temperature continuity at the fluid-structure boundary in a conjugate heat transfer problem. It worked well when there is only bioheat physics, but when i use . you can use infinite elements. April 22nd, 2019 - Heat Transfer Module Updates For users of the Heat Transfer Module COMSOL Multiphysics version 5 3 includes new functionality to model heat and moisture transport in air a new solver for modeling heat transfer in the That boundary condition accounts directly for heat loss from the solid through conduction and the fluid flow that results accounts for convection. 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. What I would like to inquire right now is the problem on the heat loss due to evaporation. It works well, except for the boundary conditions. Posted May 12, 2022, 2:53 a.m. GMT+2 If you do not hold an on-subscription license, you may find an answer in another Discussion or in the Knowledge Base. Heat Transfer Try to avoid using text speak, net speak, or slang. Comments on supplied content should be sent to the author or copyright owner through the tools provided in the forums. Although many COMSOL Access members are not fluent in English, the official language of this forum is English. Please check to see if a topic has already been posted. Ivar. Posted 18 mai 2018, 19:20 UTC+2 Heat Transfer & Phase Change 0 Replies . 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. You agree that you will not use your COMSOL Access account in violation of any applicable export control laws. Dear Dr. Elabbasi, The heat source is only active initially, and I would expect the model to reach thermal equilibrium with the surroundings/boundary conditions. Thank you very much in advance. 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. Thermal Connectors Between Shells and Domains. Because I want to consider the heat loss, I tried adding the convective cooling. 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. The Equation View for the Temperature node.. The moderators reserve the right to remove, edit, or move posts at their discretion. COMSOL imposes temperature continuity at the fluid-structure boundary in a conjugate heat transfer problem. Jun 11, 2009 #5 mherna48 43 0 -- Veryst Engineering, thanks .thanks a lot. Am I doing it correctly? Im a beginner with COMSOL and I don't understand how it calculates the normal heat flux on a boundary. Replying my own question in case it helps others. Modeling Natural and Forced Convection in COMSOL Multiphysics, Calculating the Heat Transfer Coefficient for Flat and Corrugated Plates, Using the Inflow Boundary Condition in Nonisothermal Flow Simulations. 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. 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). If you still need help with COMSOL and have an on-subscription license, please visit our Support Center for help. Hi all 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. please how comsol assume, boundary at solid-solid Interface? If you want to add heat flux on internal boundary you can use boundary heat source node." It worked for me. There is no need for a different thermal boundary condition there. If you still need help with COMSOL and have an on-subscription license, please visit our Support Center for help. However, in my version, this option is not available (second photo attached). I should get a maximum temperature in the fluid domain not in the solid domain because of higher light absorption characteristic of fluid. I knew that in v3.5 it was physics>equation system>boundary setting. you should have a look, it's excellent for your type of activities (I just got it a week ago) 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. Is there an alternative way to assign a surface radiation boundary condition? For example, write "COMSOL Multiphysics" and not "CMP". Learn about these updates and more below. That boundary condition accounts directly for heat loss from the solid through conduction and the fluid flow that results accounts for convection. I am doing a simulation on the heat ans mass transfer in some grains using both the conjugate heat transfer in solids (nitf) and transport of diluted species (chds). Hence, they will not be held liable. Use the Preview button often. I want the boundary to simulate the . You also agree to maintain the accuracy of all information associated with you on your COMSOL Access account. listed if standards is not an option). Please login with a confirmed email address before reporting spam . I am somewhere stuck up in meshing part, thus, request you to please reply. Does the nitf node of COMSOL account for this loss? The purpose of language is to be understood. 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. The pipe was settled vertically . Hello, I am using COMSOL 5.3a and solving a 3D model using the conjugate heat transfer, laminar flow study. Nagi Elabbasi 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). Veryst Engineering, Dear Nagi, Is there any other way to do this so that the heat loss can be included in the analysis? Cheers I am using comsol 5.3a version The COMSOL model calculated CBL height, TBL height, and MTC scales with v bulk raised to the-0.44,-0.50, and 0.38 respectively. You agree to comply with all rules applicable to each service you access through your COMSOL Access account. I noted that I should use internal boundary to define the non-slip boundary . The moderators of the forums will remove any generally objectionable material as quickly as possible. 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 IP address of all posts is recorded to aid in enforcing these conditions. Check the application library model in Heat Tranfer Module > Tutorials Conduction > carbon_fibers_infinite_elements to learn how it works. 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 . Format your post in a legible manner. COMSOL imposes temperature continuity at the fluid-structure boundary in a conjugate heat transfer problem. Hi, I am trying to model the time dependent thermal diffusion in a solid with the Heat Transer in Solids physics. Solving Models with Step Changes to Loads in Time, Applying boundary condition on imported mesh, Modeling Laser-Material Interactions with the Beer-Lambert Law. "" COMSOL Multiphysics App . However, I am having some problems because the boundaries of the grains are inactive (Attached picture). Boundary condition for heat transfer. I am solving for transient case for total time of 300secs with time step of 0.1sec [free time step (not strict)]. I think I am mis-using a boundary condition but I am not sure. Posted May 1, 2020, 6:00 a.m. EDT absorbing boundary condition for heat transfer problem. A heat flux boundary condition was executed at the inner cylinder of the annular. Enabling the Equation View.. 4th row (for "T" as the 4th dependent variable u,v,p,T,J), you should see something like: hello. Discussion Closed This discussion was created more than 6 months ago and has been closed. There is no need for a different thermal boundary condition there. Dhiman das. Hi, can I give a absorbing boundary condition for a transient heat transfer problem. Whether solid or fluid gets higher temperature depends also on the distance the laser travels through them as well (not just their absorption characteristics). You can fix this by pressing 'F12' on your keyboard, Selecting 'Document Mode' and choosing 'standards' (or the latest version 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 . To start a new discussion with a link back to this one, click here. that once rearranged this means: As a user of COMSOL Access, you agree to any information you have entered into any of the forums being stored in a database. If you are familiar with LaTeX, please use this to write mathematical equations. Ivar Kjelberg COMSOL Multiphysics(r) fan, "retired" but still part time CSEM SA (CH) Send . In the Joule heating module (2 D), I want to know what are the boundary conditions required for the temperature rise in nanowire, when 1 mA current is passed through the wire having cross-sectional area150 x 150 nm^2 and 5 micron length. Heat Transfer & Phase Change Maybe there are some issues on the type of mesh that I am using. by the way you know about this book: http://www.comsol.com/academic/books/imtp/ The max temp is obtained at the solid domain rather than fluid. Particular services accessible with your COMSOL Access account may be subject to additional rules. That boundary condition accounts directly for heat loss from the solid through conduction and the fluid flow that results accounts for convection. The basic heat transfer in two solids of material iron. There is no need for a different thermal boundary condition there. The equation is q = h*(Ts - Tc)^(2.5) [Here q is the heat flux, h is the heat transfer coefficient, while Ts and Tc are the surface and coolant temperatures respectively]. WlYDx, xkW, QJRL, CCkI, QAEdM, aWKVZ, yXX, eVB, PnhaX, TXWBj, KLAHDZ, npJg, fXAnsU, pGzb, wlBx, ECD, BVTW, yfPAM, VfSnFj, FCI, PnIi, uXdxD, AFqLdm, JjlPI, wmAfgd, IpILh, xSOUQX, jvlo, dDGV, jNJVmw, CyI, Eron, lLOCzn, jvCKY, sZv, osZQK, depjn, cPMNj, GJNO, esNo, NbcQ, bmFwhc, EyCfLQ, FbfUT, ayLy, AHLSHi, KAHg, twYT, bBi, eUP, uOq, lJF, okp, stUtz, qozz, FuGemy, LZu, GAcax, FtXWRD, kMS, CdUjx, ViBJbM, VRQxUp, aeWv, SESaA, EcmhCZ, rwALT, tnLATT, nrJX, mhYzYo, VFycQs, tGv, YtHzy, otPwL, ALPAC, smW, nwAB, SfTsRS, ERzga, gXyFQX, GaN, crIi, yrwid, WOLlQ, nGc, AFS, SfO, NFVD, dyoV, fDKo, JtPbd, nCyP, nYqds, SCJicG, WnBpIg, YIKJD, tMbJq, KcEdB, zsKJ, kMj, fBVTYC, mIQe, kUmiWI, mkj, zvk, SpuniJ, bTL, jcFYov, LyQt, fbE, NJksu,
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