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#1 |
Member
Yann Guyot
Join Date: Feb 2019
Posts: 37
Rep Power: 7 ![]() |
Dear All,
I am wondering if some of you use openFoam 7 to solve a case involving solarLoad. I am looking for some tutorials for such applications. Thanks a lot in advance Yann |
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#2 |
Member
Fabian Friberg
Join Date: Dec 2020
Posts: 31
Rep Power: 5 ![]() |
As far as I know OF7 doesn't have a model for solar load, only OFv2012. I'm running a case using that model.
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#3 |
Member
Yann Guyot
Join Date: Feb 2019
Posts: 37
Rep Power: 7 ![]() |
Dear Lumpor,
Do you know why such solver as been removed from newest version of OpenFoam? Do you mind sharing your case with us here? Thanks a lot |
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#4 |
Member
Fabian Friberg
Join Date: Dec 2020
Posts: 31
Rep Power: 5 ![]() |
Dear Yann,
I quickly searched on google and found a thread where you discussed the solarLoad model one year ago. The one you discussed is a part of the openfoam.com version (latest version openfoamv2012, which stands for december 2020, not year 2012), which is the same one that I'm using. It has never been a part of the openfoam.org architecture. I'm new to CFD so I'm not entirely sure about everything but I'll try my best to not give any false information. My case isn't really finished yet, I'm still trying to tune the parameters. But here are my 0/T, radiationProperties and boundaryRadiationPreperties files: T: Code:
dimensions [0 0 0 1 0 0 0]; internalField uniform 283; boundaryField { top { type symmetryPlane; } ground { // type fixedValue; // value uniform 296; //type zeroGradient; type externalWallHeatFluxTemperature; mode coefficient; Ta uniform 283; h 20; kappaMethod fluidThermo; kappa none; qr qr; value uniform 283; } front { type empty; } back { type empty; } left_in { type cyclic; } right_out { type cyclic; } upwindWall { // type fixedValue; // value uniform 296; // type zeroGradient; type externalWallHeatFluxTemperature; mode coefficient; Ta uniform 294; h 20; thicknessLayers ( 0.15 ); kappaLayers ( 0.25 ); kappaMethod fluidThermo; kappa none; qr qr; value uniform 283; } downwindWall { // type fixedValue; // value uniform 403; // type zeroGradient; type externalWallHeatFluxTemperature; mode coefficient; Ta uniform 294; h 20; thicknessLayers ( 0.15 ); kappaLayers ( 0.25 ); kappaMethod fluidThermo; kappa none; qr qr; value uniform 283; } upwindRoof { // type fixedValue; // value uniform 296; //type zeroGradient; type externalWallHeatFluxTemperature; mode coefficient; Ta uniform 294; h 20; thicknessLayers ( 0.15 ); kappaLayers ( 0.25 ); kappaMethod fluidThermo; kappa none; qr qr; value uniform 283; } downwindRoof { // type fixedValue; // value uniform 296; //type zeroGradient; type externalWallHeatFluxTemperature; mode coefficient; Ta uniform 294; h 20; thicknessLayers ( 0.15 ); kappaLayers ( 0.25 ); kappaMethod fluidThermo; kappa none; qr qr; value uniform 283; } } Code:
".*" { type transparent; wallAbsorptionEmissionModel { type multiBandAbsorption; emissivity (1 1); absorptivity (0 0); }; } //////////////////// upwindWall { type opaqueDiffusive; //fd 0.2; // 0: all specular 1: all diffusive wallAbsorptionEmissionModel { type multiBandAbsorption; absorptivity (0.2 0.3); emissivity (0.2 0.3); }; } downwindWall { type opaqueDiffusive; //fd 0.2; // 0: all specular 1: all diffusive wallAbsorptionEmissionModel { type multiBandAbsorption; absorptivity (0.2 0.3); emissivity (0.2 0.3); }; } upwindRoof { type opaqueDiffusive; wallAbsorptionEmissionModel { type multiBandAbsorption; absorptivity (0.2 0.3); emissivity (0.2 0.3); }; } downwindRoof { type opaqueDiffusive; wallAbsorptionEmissionModel { type multiBandAbsorption; absorptivity (0.2 0.3); emissivity (0.2 0.3); }; } ground { type opaqueDiffusive; wallAbsorptionEmissionModel { type multiBandAbsorption; absorptivity (0.2 0.3); emissivity (0.2 0.3); }; } Code:
radiation on; radiationModel solarLoad; solarLoadCoeffs { sunDirectionModel sunDirTracking; sunTrackingUpdateInterval 500; skyCloudCoverFraction 0.01; localStandardMeridian 1; // GMT offset (hours) startDay 180; // day of the year startTime 14; // time of the day (hours decimal) longitude 12.0; // longitude (degrees) latitude 58.0; // latitude (degrees) // Grid orientation gridUp (0 0 1);//001 gridEast (0.9 -0.1 0);//010 // Energy spectrum spectralDistribution (2 1); sunLoadModel sunLoadFairWeatherConditions; // Fair Weather Conditions Model Constants. // Calculate beta from the Solar calculator or input A 500; // Apparent solar irradiation at air mass m = 0 B 0.142064516129; // Atmospheric extinction coefficient // Ground reflectivity groundReflectivity 0.2; // Solar diffusivity constants C 0.058064516129; // Model constant // Radiative flux coupling flags wallCoupled true; // Couple through Qr wall patches (default false) // Reflecting rays useReflectedRays false; reflecting { nPhi 10; nTheta 10; } absorptionEmissionModel none; scatterModel none; sootModel none; } // Number of flow iterations per radiation iteration solverFreq 100; absorptionEmissionModel none; scatterModel none; sootModel none; I tried to combine the solarLoad with a view factor model, but couldn't get it to work ![]() If you have any specific questions I can try to answer them. I've done some modifying inside the solarLoad library so I know a bit how it works at a lower level. Best regards, Fabian Last edited by lumpor; March 23, 2021 at 07:04. |
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#5 |
Member
Yann Guyot
Join Date: Feb 2019
Posts: 37
Rep Power: 7 ![]() |
Thank you very much, I actually had no idea about this 2 versions (indeed, i thought 2012 was for the year). So there is two major release, the ESI release and the Foundation releas, both are up to date.
I will check about them both, Thanks a lot Yann |
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#6 |
Member
Fabian Friberg
Join Date: Dec 2020
Posts: 31
Rep Power: 5 ![]() |
Yup, I myself was also very confused by it. Took me several days to figure out I was using the wrong OF version.
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#7 |
Senior Member
Mark Olesen
Join Date: Mar 2009
Location: https://olesenm.github.io/
Posts: 1,714
Rep Power: 40 ![]() ![]() |
At least when the v2106 comes out, there shouldn't be any confusion about its age.
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#8 | |
Senior Member
Mark Olesen
Join Date: Mar 2009
Location: https://olesenm.github.io/
Posts: 1,714
Rep Power: 40 ![]() ![]() |
Quote:
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#9 |
Member
Fabian Friberg
Join Date: Dec 2020
Posts: 31
Rep Power: 5 ![]() |
Ah I see. I'll edit it.
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#10 |
New Member
Abbes
Join Date: Apr 2022
Posts: 5
Rep Power: 4 ![]() |
hello every one,
i'm a new OpenFoam User ( i actually use OpenFOAM-v2006 with a graphic user interface for my master thesis) i want to do a natural ventilation simulation in a house exposed to solar radiation i began with simulating an external flow over building with solar load ( with BuoyantSimpleFoam Solver) to get the external temperature but it gives very high temperature ( about 500 K) which is not reasonable. is this because there is no radiation model ? then i switched to ChtMultiRegionSimpleFoam with two Region solid and fluid but it doesn't work it crashes from the start my questions are: - how to simulate this type of cases to get reasonable temperature. - what a solver to use for this case - did ChtMultiRegionSimpleFoam support Solar load on OpenFoam v2006 (june 2020). - if you have any clue or tutorial that can help me for solarload application please help i'm lost i can't find any tutorial or a paper for this. please find attached some pictures of my case ( for BuoyantSimpleFoam) Regards Abbes |
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#11 | |||
Member
Fabian Friberg
Join Date: Dec 2020
Posts: 31
Rep Power: 5 ![]() |
Quote:
1. While it's more realistic to simulate heat loss using radiation, I ended up simply utilizing boundary conditions to keep the temperature low. Here's are two excerpts from my thesis: Quote:
Quote:
https://www.overleaf.com/read/mtntmznmtrqv 2. I made solar radiation work using rhoReactingFoam (which I used due to my case including chemical reactions). I think ChtMultiRegionSimpleFoam is a good choice for you, if you can make it work. The multiregion ones are quite difficult though. 3. One of the solarload tutorials uses it doesn't it? I think the one with trees. Then there was one in a car that was quite useful to me, and then there's one using ChtMultiRegionFoam with a cube in the middle. 4. Recalling from memory there were 3 or so tutorials utilizing solar radiation. The grep command is your friend. Other than that, the files posted earlier in this thread and my thesis, I don't know of any resources, sorry :/ (For boundary conditions, the book Boundary Conditions - OpenFOAM-4.1 by NEXTFOAM ain't bad) |
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#12 | |
New Member
Abbes
Join Date: Apr 2022
Posts: 5
Rep Power: 4 ![]() |
Quote:
i'm a beginner user of OF, i will see your thesis for more information. i just find the tutorials that you talk about i will chek it to understand how they did for such kind a case, it will help me for sure. -if i understood well, you didn't use radiation model and A is it the incident solar radiation ( from Radiation properties) ? Ta is the ambiant temperature defined in BC 0/T e - for my case the q is set to flux, i will try to set it to coefficient and see the difference. -for me i didn't define a wall tickness ( left at 0) maybe because of this i got high temperature ( there is a part of flux that can be conducted through the walls), i assume that you considered the wall thickness. is it the kappaLayers and thicknessLayers. that give condictivity and thickness for every layers? and also because the surfaces emissivity and absortivity=1 of all, that makes them absorb all the solar radiation ( i actually tried to reduce emissivity and absortivity to 0.5, the temperature had decreased about 100K to 200K. thank you again, you really gave me some clues, i'll read your thesis, I'll come back to you, if I have questions please find joined T, U, Radiations and boundaryRadiationProperties which explain if you will have any observations. please,excuse me for my english. Ragards Abbes |
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#13 | ||||
Member
Fabian Friberg
Join Date: Dec 2020
Posts: 31
Rep Power: 5 ![]() |
Hi, sorry for the late reply
Quote:
Quote:
Quote:
If you don't have any walls, it would then be 1/1=1. Quote:
thank you again, you really gave me some clues, i'll read your thesis, I'll come back to you, if I have questions please find joined T, U, Radiations and boundaryRadiationProperties which explain if you will have any observations. Abbes[/QUOTE] I had a quick check and didn't see anything that looked too bad. But once again I'm far from an expert, sorry :P I'll attach the final version of my files if you're interested, some of the values should be updated from my earlier post. Good luck! I know how hard it can be with limited documentation on the resources you're using. boundaryRadiationProperties.txt radiationProperties.txt T.txt |
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#14 |
New Member
Abbes
Join Date: Apr 2022
Posts: 5
Rep Power: 4 ![]() |
thank you so much, i really appreciate your help
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