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Problem with chtMultiregionFoam radiation boundary condition 

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August 19, 2015, 06:48 
Problem with chtMultiregionFoam radiation boundary condition

#1 
Member
baran
Join Date: Aug 2014
Posts: 45
Rep Power: 10 
Greeting all!!!
I have a simple case as follows...in OF 2.4 1. Cavity with heater inside 2. Surrounding this cavity some insulation is there So I run the radiation case(with view factor model) in chtMultiregionFoam(transient) with interface boundary condition of solid and air.. Code:
type compressible::turbulentTemperatureCoupledBaffleMixed; value uniform 300; Tnbr T; kappa fluidThermo; kappaName none; Code:
Region: fluid Courant Number mean: 0.009927002 max: 0.29967996 Region: fibrothal_in Diffusion Number mean: 5.0662336e08 max: 3.0645162e07 Region: solid_bricks Diffusion Number mean: 3.3063735e08 max: 1.7757998e07 Region: unifrax_out Diffusion Number mean: 1.0011137e07 max: 3.0843423e07 deltaT = 0.0010946195 Time = 356.6388 Solving for fluid region fluid diagonal: Solving for rho, Initial residual = 0, Final residual = 0, No Iterations 0 DILUPBiCG: Solving for Ux, Initial residual = 0.00025637481, Final residual = 4.407068e09, No Iterations 2 DILUPBiCG: Solving for Uy, Initial residual = 0.00027934907, Final residual = 9.510753e09, No Iterations 2 DILUPBiCG: Solving for Uz, Initial residual = 0.0002301347, Final residual = 1.7324477e09, No Iterations 2 DILUPBiCG: Solving for h, Initial residual = 3.1476392e05, Final residual = 7.3471181e08, No Iterations 1 Min/max T:313.58391 1118 GAMG: Solving for p_rgh, Initial residual = 8.5854497e05, Final residual = 9.4845113e08, No Iterations 7 GAMG: Solving for p_rgh, Initial residual = 3.5173418e06, Final residual = 5.4325282e08, No Iterations 3 GAMG: Solving for p_rgh, Initial residual = 8.6238562e07, Final residual = 3.8513529e08, No Iterations 2 diagonal: Solving for rho, Initial residual = 0, Final residual = 0, No Iterations 0 time step continuity errors (fluid): sum local = 6.074565e10, global = 6.3652211e13, cumulative = 2.197283e07 GAMG: Solving for p_rgh, Initial residual = 1.0315776e06, Final residual = 3.9160376e08, No Iterations 2 GAMG: Solving for p_rgh, Initial residual = 1.669925e07, Final residual = 2.9482081e08, No Iterations 1 GAMG: Solving for p_rgh, Initial residual = 6.8532497e08, Final residual = 6.8532497e08, No Iterations 0 diagonal: Solving for rho, Initial residual = 0, Final residual = 0, No Iterations 0 time step continuity errors (fluid): sum local = 1.080931e09, global = 4.0250703e14, cumulative = 2.1972834e07 Solving for solid region fibrothal_in DICPCG: Solving for h, Initial residual = 1.2940158e06, Final residual = 1.3251284e12, No Iterations 1 DICPCG: Solving for h, Initial residual = 1.7071703e12, Final residual = 1.7071703e12, No Iterations 0 Min/max T:min(T) [0 0 0 1 0 0 0] 300 max(T) [0 0 0 1 0 0 0] 640.55258 Solving for solid region solid_bricks DICPCG: Solving for h, Initial residual = 1.0267441e06, Final residual = 4.8127074e13, No Iterations 1 DICPCG: Solving for h, Initial residual = 8.4350547e13, Final residual = 8.4350547e13, No Iterations 0 Min/max T:min(T) [0 0 0 1 0 0 0] 300 max(T) [0 0 0 1 0 0 0] 458.84315 Solving for solid region unifrax_out DICPCG: Solving for h, Initial residual = 9.9373252e07, Final residual = 9.9373252e07, No Iterations 0 DICPCG: Solving for h, Initial residual = 9.9373252e07, Final residual = 9.9373252e07, No Iterations 0 Min/max T:min(T) [0 0 0 1 0 0 0] 300 max(T) [0 0 0 1 0 0 0] 303.89972 ExecutionTime = 133423.49 s ClockTime = 136999 s Region: fluid Courant Number mean: 0.0099269187 max: 0.29966461 Region: fibrothal_in Diffusion Number mean: 5.0662347e08 max: 3.0645172e07 Region: solid_bricks Diffusion Number mean: 3.3063735e08 max: 1.7757998e07 Region: unifrax_out Diffusion Number mean: 1.0011137e07 max: 3.0843423e07 deltaT = 0.0010946195 Time = 356.6399 Solving for fluid region fluid diagonal: Solving for rho, Initial residual = 0, Final residual = 0, No Iterations 0 DILUPBiCG: Solving for Ux, Initial residual = 0.00025636135, Final residual = 4.3780302e09, No Iterations 2 DILUPBiCG: Solving for Uy, Initial residual = 0.00027935499, Final residual = 1.0088861e08, No Iterations 2 DILUPBiCG: Solving for Uz, Initial residual = 0.00023013524, Final residual = 1.6871542e09, No Iterations 2 DILUPBiCG: Solving for h, Initial residual = 3.1473979e05, Final residual = 7.3570805e08, No Iterations 1 Min/max T:313.58441 1118 GAMG: Solving for p_rgh, Initial residual = 8.5834205e05, Final residual = 9.5254497e08, No Iterations 7 GAMG: Solving for p_rgh, Initial residual = 3.5163029e06, Final residual = 5.4570072e08, No Iterations 3 GAMG: Solving for p_rgh, Initial residual = 8.6202952e07, Final residual = 3.8610652e08, No Iterations 2 diagonal: Solving for rho, Initial residual = 0, Final residual = 0, No Iterations 0 time step continuity errors (fluid): sum local = 6.0899296e10, global = 6.481879e13, cumulative = 2.1972769e07 GAMG: Solving for p_rgh, Initial residual = 1.0315463e06, Final residual = 3.9050125e08, No Iterations 2 GAMG: Solving for p_rgh, Initial residual = 1.6693103e07, Final residual = 2.9416253e08, No Iterations 1 GAMG: Solving for p_rgh, Initial residual = 6.8558156e08, Final residual = 6.8558156e08, No Iterations 0 diagonal: Solving for rho, Initial residual = 0, Final residual = 0, No Iterations 0 time step continuity errors (fluid): sum local = 1.081336e09, global = 3.652917e14, cumulative = 2.1972773e07 Solving for solid region fibrothal_in DICPCG: Solving for h, Initial residual = 1.2940145e06, Final residual = 1.3250951e12, No Iterations 1 DICPCG: Solving for h, Initial residual = 1.7071583e12, Final residual = 1.7071583e12, No Iterations 0 Min/max T:min(T) [0 0 0 1 0 0 0] 300 max(T) [0 0 0 1 0 0 0] 640.55404 Solving for solid region solid_bricks DICPCG: Solving for h, Initial residual = 1.0267414e06, Final residual = 4.812706e13, No Iterations 1 DICPCG: Solving for h, Initial residual = 8.4350791e13, Final residual = 8.4350791e13, No Iterations 0 Min/max T:min(T) [0 0 0 1 0 0 0] 300 max(T) [0 0 0 1 0 0 0] 458.84273 Solving for solid region unifrax_out DICPCG: Solving for h, Initial residual = 9.9373296e07, Final residual = 9.9373296e07, No Iterations 0 DICPCG: Solving for h, Initial residual = 9.9373296e07, Final residual = 9.9373296e07, No Iterations 0 Min/max T:min(T) [0 0 0 1 0 0 0] 300 max(T) [0 0 0 1 0 0 0] 303.89975 ExecutionTime = 133424 s ClockTime = 137000 s Code:
type compressible::turbulentTemperatureRadCoupledMixed; value uniform 300; Tnbr T; kappa fluidThermo; QrNbr none; Qr Qr; kappaName none; Code:
solvers { rho { solver PCG; preconditioner DIC; tolerance 1e7; relTol 0; } rhoFinal { $rho; tolerance 1e7; relTol 0; } p_rgh { solver GAMG; tolerance 1e7; relTol 0; smoother GaussSeidel; cacheAgglomeration true; nCellsInCoarsestLevel 10; agglomerator faceAreaPair; mergeLevels 1; } p_rghFinal { $p_rgh; tolerance 1e7; relTol 0; } "(UhkomegaepsilonR)" { solver PBiCG; preconditioner DILU; tolerance 1e7; relTol 0.1; } "(UhkomegaepsilonR)Final" { $U; tolerance 1e7; relTol 0; } } PIMPLE { momentumPredictor on; nCorrectors 2; nNonOrthogonalCorrectors 2; } relaxationFactors { fields { rho 0.1; p_rgh 0.1; } equations { "h.*" 0.1; "U.*" 0.1; "(kepsilonR)" 0.1; G 0.1; "ILambda.*" 0.1; Qr 0.1; } } Code:
ddtSchemes { default Euler; } gradSchemes { default cellLimited Gauss linear 1; // Gauss linear; } divSchemes { default none; div(phi,U) Gauss upwind; div(phi,k) Gauss upwind; div(phi,K) Gauss linear; // Gauss upwind; div(phi,epsilon) Gauss upwind; div(phi,h) Gauss upwind; div(phi,omega) Gauss upwind; div(phi,R) Gauss upwind; div(R) Gauss linear; div(Ji,Ii_h) Gauss linearUpwind grad(U); div((muEff*dev2(T(grad(U))))) Gauss linear; } laplacianSchemes { default none; laplacian(rhorAUf,p_rgh) Gauss linear limited 0.333; laplacian(muEff,U) Gauss linear limited 0.333; laplacian((rho*(1A(U))),p_rgh) Gauss linear limited 0.333; laplacian(alphaEff,h) Gauss linear limited 0.333; laplacian(DepsilonEff,epsilon) Gauss linear limited 0.333; laplacian(DkEff,k) Gauss linear limited 0.333; laplacian(DomegaEff,omega) Gauss linear limited 0.333; laplacian(DREff,R) Gauss linear limited 0.333; laplacian(gammaRad,G) Gauss linear limited 0.333; } interpolationSchemes { default linear; } snGradSchemes { default limited 0.333; } fluxRequired { default no; p_rgh; } Code:
Maximum numbers of iterations exceeded Apart from this bc remaining thing is same for two cases...Is there is a problem with this boundary condition..?? Please suggest something... 

August 20, 2015, 09:01 

#2 
Senior Member
Alex
Join Date: Oct 2013
Posts: 337
Rep Power: 20 
Hi baran,
You did good in providing as much information as you could. However, maybe more information might be needed in order to figure out what is going wrong in your case. For instance, you should upload the log file of the run that crashed in order to be able to start guessing things... For how long has it been runing? In the last cases I run where radaitive heat transfer was taken into account I found out that the balance on patches was somewhat critical in the first time steps. It was due to the sudden variation of the gradients at patches when radiation was computed. However, I never faced this problem with the turbulentTemperatureRadCoupledMixed patch type, but I had some similar issue with thermalBaffle1D and externalWallHeatFluxTemperature instead. The solution to avoid getting a crashed run was to implement a relaxation factor method to prevent the already mentioned problem of gradient variation. You should take a look into the code of these BC's in order to understand what I am talking about, maybe something like that may be usefull. Nevertheless, I recall that I never had this problem with the turbulentTemperatureRadCoupledMixed patch type... Have you used any of the other mentioned patch types in your simulation? Another advice I give you is that you should try to visualize with paraview the thermal distribution in the last time step before the run crashed. By doing that you could be able to find out what cells are causing the trouble. After that you can start guessing what is going wrong with more accuracy. I hope my advices will come in handy to you. Best regards, Alex _______________________ Quick update: I worked with chtMultiRegionSimpleFoam solver and radiation was solved with fvDOM method in my case.
__________________
Web site where I present my Master's Thesis: foamingtime.wordpress.com The case I talk about in this site was solved with chtMultiRegionSimpleFoam solver and involves radiation. Some basic tutorials are also resolved step by step in the web. If you are interested in these matters, you are invited to come in! Last edited by zfaraday; August 20, 2015 at 09:03. Reason: Quick update added 

August 20, 2015, 10:29 

#3  
Member
baran
Join Date: Aug 2014
Posts: 45
Rep Power: 10 
This is the log file of that case....from where it is started diverging...
Quote:
Last edited by baran_foam; August 20, 2015 at 10:30. Reason: modify 

August 20, 2015, 15:30 

#4 
Retired Super Moderator
Bruno Santos
Join Date: Mar 2009
Location: Lisbon, Portugal
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Greetings to all!
@baran_foam: Since you sent me a PM and I spent some time trying to imagine/diagnose this issue, my best guess is that there is no heat being released by the region "solid_bricks", which is why it ends up overheating and crashing the simulation, because the temperature range falls out of the working range of the polynomials for the material properties. Beyond that, you should follow Alex's suggestion, specially the one about looking at the results in ParaView. Best regards, Bruno
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August 24, 2015, 02:17 

#5 
Member
baran
Join Date: Aug 2014
Posts: 45
Rep Power: 10 
Greeting All!!!
@bruno ....thanks for your reply....and I will check that issue... @Alex... thanks for your valuable suggestion... 1. for bc in heating element surface I have used uniformFixedValue 2. for outer wall I have used Code:
type externalWallHeatFluxTemperature; kappa solidThermo; Ta uniform 303; h uniform 10; kappaName none; value uniform 300; can you kindly explain what kind of problem you faced with externalWallHeatFluxTemperature bc? I have to check other things as you told and let you know wheather any other issue is there or not... Regards, Baran 

August 24, 2015, 09:54 

#6 
Senior Member
Alex
Join Date: Oct 2013
Posts: 337
Rep Power: 20 
Hi baran,
You can check youself the problem I faced here. What OF version are you using? If you use 2.3.x or 2.4.x you can fix it by downloading the fixes via github and recompile it. The fix consists of a relaxation factor implemented for the Qr field so that you only need to specify a couple of fields more in the BC specification. By the way, in the BC specification you attached you din't have Qr defined and you need to define it in order to take radiation into account in the boundaries... Hope it helps! Alex
__________________
Web site where I present my Master's Thesis: foamingtime.wordpress.com The case I talk about in this site was solved with chtMultiRegionSimpleFoam solver and involves radiation. Some basic tutorials are also resolved step by step in the web. If you are interested in these matters, you are invited to come in! 

August 26, 2015, 08:21 

#7 
Member
baran
Join Date: Aug 2014
Posts: 45
Rep Power: 10 
Dear Alex,
my OF version is 2.4.x This same case I have run in fluent to compare the two result . As thermal conductivity is very low of this solid zone. Wheather I add radiation at the outer wall does not have any effect. Thermal conductivity of bricks is 0.15 . I want to ask another question..that..if I am applying viewfactor model but wall bc is like convection case then viewfactor effect is come into consideration? Regards, baran 

August 31, 2015, 07:02 

#8 
Member
baran
Join Date: Aug 2014
Posts: 45
Rep Power: 10 
Greeting all!!!
This is mesh quality of my geometry...I hope this is not made any problem... Code:
Create polyMesh for time = 0 Enabling all (cell, face, edge, point) topology checks. Enabling all geometry checks. Time = 0 Mesh stats points: 1116300 faces: 3270406 internal faces: 3191462 cells: 1076978 faces per cell: 6 boundary patches: 10 point zones: 0 face zones: 13 cell zones: 4 Overall number of cells of each type: hexahedra: 1076978 prisms: 0 wedges: 0 pyramids: 0 tet wedges: 0 tetrahedra: 0 polyhedra: 0 Checking topology... Boundary definition OK. Cell to face addressing OK. Point usage OK. Upper triangular ordering OK. Face vertices OK. Topological cell zipup check OK. Faceface connectivity OK. Number of regions: 1 (OK). Checking patch topology for multiply connected surfaces... Patch Faces Points Surface topology Bounding box he_surface 13720 13736 ok (closed singly connected) (0.247 0.251 0.272) (0.917 0.941 1.202) w_right_side_ref 5952 6111 ok (nonclosed singly connected) (2.6999174e24 0.15 0.212) (5.2351103e16 1.036 1.352) w_left_side_ref 5952 6111 ok (nonclosed singly connected) (1.164 0.15 0.212) (1.164 1.036 1.352) w_back_ref 12288 12513 ok (nonclosed singly connected) (0 0.15 1.352) (1.164 1.036 1.502) w_brick_bot 3256 3500 ok (nonclosed singly connected) (0.217 9.5154073e16 0.212) (0.947 9.5707519e16 1.352) w_bot_ref 7104 7499 ok (nonclosed singly connected) (0 1.1571817e15 0.212) (1.164 0.15 1.502) w_door1 2588 2676 ok (nonclosed singly connected) (0.332 0.356 0.1) (0.832 0.85600003 0.05) w_door2 696 870 ok (nonclosed singly connected) (0.332 0.356 0.05) (0.832 0.85600003 0) w_bricks 17028 17343 ok (nonclosed singly connected) (0 1.1571817e15 0) (1.164 1.186 0.212) w_top_ref 10360 10553 ok (nonclosed singly connected) (0 1.036 0.212) (1.164 1.186 1.502) Checking geometry... Overall domain bounding box (0 1.1571817e15 0.1) (1.164 1.186 1.502) Mesh (nonempty, nonwedge) directions (1 1 1) Mesh (nonempty) directions (1 1 1) Boundary openness (3.2928793e15 2.2620737e15 7.0567305e15) OK. Max cell openness = 3.3154974e16 OK. Max aspect ratio = 13.162501 OK. Minimum face area = 6.5776377e06. Maximum face area = 0.00064648215. Face area magnitudes OK. Min volume = 8.3282847e08. Max volume = 7.9145335e06. Total volume = 2.0928022. Cell volumes OK. Mesh nonorthogonality Max: 69.14912 average: 8.4597446 Nonorthogonality check OK. Face pyramids OK. Max skewness = 0.66268921 OK. Coupled point location match (average 0) OK. Face tets OK. Min/max edge length = 0.0016666666 0.032313618 OK. All angles in faces OK. Face flatness (1 = flat, 0 = butterfly) : min = 0.99388226 average = 0.99999605 All face flatness OK. Cell determinant (wellposedness) : minimum: 0.028461416 average: 4.6877314 Cell determinant check OK. Concave cell check OK. Face interpolation weight : minimum: 0.10005566 average: 0.49007212 Face interpolation weight check OK. Face volume ratio : minimum: 0.11131699 average: 0.9662018 Face volume ratio check OK. Mesh OK. Can you suggest what might be the reason?? From the discussion of our previous case it is observed that case is diverging for radiation case...in bricks zone(thermal conductivity0.15 J/kg K) So I change the thermal conductivity of bricks from 0.15 to 10. Then run the same case with radiation bc.... Then case is diverging in other zone..fibrothal(thermal conductivity is around 0.15 J/kg K)...So is there is any problem with this radiation bc or radiation to handle high T with small thermal conductivity of insulation.. Please suggest something...mostly this problem is not involve with any mesh issue...??? I have attached the log file for the later case below... Code:
Region: fluid Courant Number mean: 0.0198761 max: 0.29878319 Region: fibrothal_in Diffusion Number mean: 5.3692836e08 max: 3.868369e07 Region: solid_bricks Diffusion Number mean: 2.453461e06 max: 1.317393e05 Region: unifrax_out Diffusion Number mean: 1.0442085e07 max: 3.2171136e07 deltaT = 0.0011417394 Time = 132.83673 Solving for fluid region fluid diagonal: Solving for rho, Initial residual = 0, Final residual = 0, No Iterations 0 DILUPBiCG: Solving for Ux, Initial residual = 7.8428474e05, Final residual = 2.3160953e08, No Iterations 1 DILUPBiCG: Solving for Uy, Initial residual = 5.9872307e05, Final residual = 2.1848024e08, No Iterations 1 DILUPBiCG: Solving for Uz, Initial residual = 8.1347697e05, Final residual = 1.7257565e08, No Iterations 1 DILUPBiCG: Solving for h, Initial residual = 1.3754107e05, Final residual = 1.8032295e09, No Iterations 1 Min/max T:306.56532 939 GAMG: Solving for p_rgh, Initial residual = 0.004153507, Final residual = 8.7413984e08, No Iterations 10 GAMG: Solving for p_rgh, Initial residual = 8.9189776e06, Final residual = 8.0399224e08, No Iterations 4 GAMG: Solving for p_rgh, Initial residual = 2.1315608e06, Final residual = 7.7674832e08, No Iterations 2 diagonal: Solving for rho, Initial residual = 0, Final residual = 0, No Iterations 0 time step continuity errors (fluid): sum local = 6.4079763e11, global = 8.4405831e13, cumulative = 1.0816831e07 GAMG: Solving for p_rgh, Initial residual = 7.9826171e07, Final residual = 3.8468735e08, No Iterations 2 GAMG: Solving for p_rgh, Initial residual = 2.8369056e07, Final residual = 4.4607049e08, No Iterations 1 GAMG: Solving for p_rgh, Initial residual = 1.209402e07, Final residual = 2.6745305e08, No Iterations 1 diagonal: Solving for rho, Initial residual = 0, Final residual = 0, No Iterations 0 time step continuity errors (fluid): sum local = 2.2064599e11, global = 8.3155456e15, cumulative = 1.0816832e07 Solving for solid region fibrothal_in DICPCG: Solving for h, Initial residual = 4.8433956e06, Final residual = 5.6555918e12, No Iterations 1 DICPCG: Solving for h, Initial residual = 5.846885e12, Final residual = 5.846885e12, No Iterations 0 Min/max T:min(T) [0 0 0 1 0 0 0] 300 max(T) [0 0 0 1 0 0 0] 823.55181 Solving for solid region solid_bricks DICPCG: Solving for h, Initial residual = 5.3780627e06, Final residual = 1.8628724e10, No Iterations 1 DICPCG: Solving for h, Initial residual = 1.9739328e10, Final residual = 1.9739328e10, No Iterations 0 Min/max T:min(T) [0 0 0 1 0 0 0] 300.00584 max(T) [0 0 0 1 0 0 0] 390.0248 Solving for solid region unifrax_out DICPCG: Solving for h, Initial residual = 3.1120483e06, Final residual = 3.4748384e12, No Iterations 1 DICPCG: Solving for h, Initial residual = 3.5734963e12, Final residual = 3.5734963e12, No Iterations 0 Min/max T:min(T) [0 0 0 1 0 0 0] 300 max(T) [0 0 0 1 0 0 0] 317.42316 ExecutionTime = 48515.92 s ClockTime = 49698 s Region: fluid Courant Number mean: 0.019876 max: 0.29877615 Region: fibrothal_in Diffusion Number mean: 5.3692908e08 max: 3.8683897e07 Region: solid_bricks Diffusion Number mean: 2.453461e06 max: 1.317393e05 Region: unifrax_out Diffusion Number mean: 1.0442085e07 max: 3.2171136e07 deltaT = 0.0011417394 Time = 132.83787 Solving for fluid region fluid diagonal: Solving for rho, Initial residual = 0, Final residual = 0, No Iterations 0 DILUPBiCG: Solving for Ux, Initial residual = 7.8490734e05, Final residual = 2.314818e08, No Iterations 1 DILUPBiCG: Solving for Uy, Initial residual = 5.9735226e05, Final residual = 2.1923582e08, No Iterations 1 DILUPBiCG: Solving for Uz, Initial residual = 8.1540717e05, Final residual = 1.7182041e08, No Iterations 1 DILUPBiCG: Solving for h, Initial residual = 1.3757046e05, Final residual = 1.804325e09, No Iterations 1 LU Back substitute C matrix.. Min/max T:306.56544 939 GAMG: Solving for p_rgh, Initial residual = 0.0041498473, Final residual = 9.054912e08, No Iterations 9 GAMG: Solving for p_rgh, Initial residual = 8.3165628e06, Final residual = 7.0594986e08, No Iterations 4 GAMG: Solving for p_rgh, Initial residual = 2.032543e06, Final residual = 6.9336629e08, No Iterations 2 diagonal: Solving for rho, Initial residual = 0, Final residual = 0, No Iterations 0 time step continuity errors (fluid): sum local = 5.7201248e11, global = 9.3147623e13, cumulative = 1.0816739e07 GAMG: Solving for p_rgh, Initial residual = 7.6577489e07, Final residual = 9.7339006e08, No Iterations 1 GAMG: Solving for p_rgh, Initial residual = 2.8026848e07, Final residual = 5.1413822e08, No Iterations 1 GAMG: Solving for p_rgh, Initial residual = 1.298081e07, Final residual = 2.9943948e08, No Iterations 1 diagonal: Solving for rho, Initial residual = 0, Final residual = 0, No Iterations 0 time step continuity errors (fluid): sum local = 2.4703296e11, global = 6.8827074e13, cumulative = 1.081667e07 Solving for solid region fibrothal_in DICPCG: Solving for h, Initial residual = 4.8426671e06, Final residual = 5.6623743e12, No Iterations 1 DICPCG: Solving for h, Initial residual = 4.4247984e11, Final residual = 4.4247984e11, No Iterations 0 Min/max T:min(T) [0 0 0 1 0 0 0] 168.02419 max(T) [0 0 0 1 0 0 0] 823.54449 Solving for solid region solid_bricks DICPCG: Solving for h, Initial residual = 5.3882983e06, Final residual = 1.8640842e10, No Iterations 1 DICPCG: Solving for h, Initial residual = 3.0063655e10, Final residual = 3.0063655e10, No Iterations 0 Min/max T:min(T) [0 0 0 1 0 0 0] 300.00584 max(T) [0 0 0 1 0 0 0] 390.07683 Solving for solid region unifrax_out DICPCG: Solving for h, Initial residual = 3.1120344e06, Final residual = 3.4748206e12, No Iterations 1 DICPCG: Solving for h, Initial residual = 3.5760929e12, Final residual = 3.5760929e12, No Iterations 0 Min/max T:min(T) [0 0 0 1 0 0 0] 300 max(T) [0 0 0 1 0 0 0] 317.42353 ExecutionTime = 48516.76 s ClockTime = 49698 s Region: fluid Courant Number mean: 0.019875904 max: 0.29876907 Region: fibrothal_in Diffusion Number mean: 5.369298e08 max: 3.8684106e07 Region: solid_bricks Diffusion Number mean: 2.453461e06 max: 1.317393e05 Region: unifrax_out Diffusion Number mean: 1.0442085e07 max: 3.2171136e07 deltaT = 0.0011417394 Time = 132.83901 Solving for fluid region fluid diagonal: Solving for rho, Initial residual = 0, Final residual = 0, No Iterations 0 DILUPBiCG: Solving for Ux, Initial residual = 7.8363917e05, Final residual = 2.3111003e08, No Iterations 1 DILUPBiCG: Solving for Uy, Initial residual = 5.9808245e05, Final residual = 2.181205e08, No Iterations 1 DILUPBiCG: Solving for Uz, Initial residual = 8.1303226e05, Final residual = 1.7190079e08, No Iterations 1 DILUPBiCG: Solving for h, Initial residual = 1.3769818e05, Final residual = 1.8025345e09, No Iterations 1 Min/max T:34.638404 939 GAMG: Solving for p_rgh, Initial residual = 0.0041635193, Final residual = 8.7220279e08, No Iterations 18 GAMG: Solving for p_rgh, Initial residual = 3.0025266e05, Final residual = 8.3696645e08, No Iterations 7 GAMG: Solving for p_rgh, Initial residual = 6.9780425e06, Final residual = 9.4629866e08, No Iterations 3 diagonal: Solving for rho, Initial residual = 0, Final residual = 0, No Iterations 0 time step continuity errors (fluid): sum local = 7.8066502e11, global = 1.0715968e11, cumulative = 1.0815598e07 GAMG: Solving for p_rgh, Initial residual = 2.6392854e06, Final residual = 8.7769725e08, No Iterations 2 GAMG: Solving for p_rgh, Initial residual = 9.0381004e07, Final residual = 4.9359257e08, No Iterations 2 GAMG: Solving for p_rgh, Initial residual = 3.9857535e07, Final residual = 5.3627197e08, No Iterations 1 diagonal: Solving for rho, Initial residual = 0, Final residual = 0, No Iterations 0 time step continuity errors (fluid): sum local = 4.4241536e11, global = 2.0258428e12, cumulative = 1.0815801e07 Solving for solid region fibrothal_in DICPCG: Solving for h, Initial residual = 4.8427064e06, Final residual = 5.6629409e12, No Iterations 1 DICPCG: Solving for h, Initial residual = 1.9117983e11, Final residual = 1.9117983e11, No Iterations 0 Min/max T:min(T) [0 0 0 1 0 0 0] 34.64088 max(T) [0 0 0 1 0 0 0] 823.55061 Solving for solid region solid_bricks DICPCG: Solving for h, Initial residual = 5.3881957e06, Final residual = 1.8640995e10, No Iterations 1 DICPCG: Solving for h, Initial residual = 1.9768437e10, Final residual = 1.9768437e10, No Iterations 0 Min/max T:min(T) [0 0 0 1 0 0 0] 300.00584 max(T) [0 0 0 1 0 0 0] 390.07814 Solving for solid region unifrax_out DICPCG: Solving for h, Initial residual = 3.1120205e06, Final residual = 3.4748029e12, No Iterations 1 DICPCG: Solving for h, Initial residual = 3.5713957e12, Final residual = 3.5713957e12, No Iterations 0 Min/max T:min(T) [0 0 0 1 0 0 0] 300 max(T) [0 0 0 1 0 0 0] 317.42391 ExecutionTime = 48517.36 s ClockTime = 49699 s Region: fluid Courant Number mean: 0.019875807 max: 0.29875958 Region: fibrothal_in Diffusion Number mean: 5.3693051e08 max: 3.8684315e07 Region: solid_bricks Diffusion Number mean: 2.453461e06 max: 1.317393e05 Region: unifrax_out Diffusion Number mean: 1.0442085e07 max: 3.2171136e07 deltaT = 0.0011417394 Time = 132.84016 Solving for fluid region fluid diagonal: Solving for rho, Initial residual = 0, Final residual = 0, No Iterations 0 DILUPBiCG: Solving for Ux, Initial residual = 8.1108496e05, Final residual = 2.5818077e08, No Iterations 1 DILUPBiCG: Solving for Uy, Initial residual = 6.134127e05, Final residual = 2.4355749e08, No Iterations 1 DILUPBiCG: Solving for Uz, Initial residual = 8.5046122e05, Final residual = 1.9803553e08, No Iterations 1 DILUPBiCG: Solving for h, Initial residual = 1.3767232e05, Final residual = 1.8025597e09, No Iterations 1 Min/max T:168.04889 939 GAMG: Solving for p_rgh, Initial residual = 0.0041488398, Final residual = 9.7922006e08, No Iterations 16 GAMG: Solving for p_rgh, Initial residual = 2.5548778e05, Final residual = 8.2376033e08, No Iterations 7 GAMG: Solving for p_rgh, Initial residual = 6.7243635e06, Final residual = 5.251697e08, No Iterations 4 diagonal: Solving for rho, Initial residual = 0, Final residual = 0, No Iterations 0 time step continuity errors (fluid): sum local = 4.3325191e11, global = 5.3072732e12, cumulative = 1.0816332e07 GAMG: Solving for p_rgh, Initial residual = 1.8993958e06, Final residual = 6.9772195e08, No Iterations 2 GAMG: Solving for p_rgh, Initial residual = 6.1908036e07, Final residual = 8.0077444e08, No Iterations 1 GAMG: Solving for p_rgh, Initial residual = 2.4772369e07, Final residual = 4.5438216e08, No Iterations 1 diagonal: Solving for rho, Initial residual = 0, Final residual = 0, No Iterations 0 time step continuity errors (fluid): sum local = 3.7486014e11, global = 1.2021921e12, cumulative = 1.0816452e07 Solving for solid region unifrax_out DICPCG: Solving for h, Initial residual = 3.1120066e06, Final residual = 3.4747852e12, No Iterations 1 DICPCG: Solving for h, Initial residual = 3.5740577e12, Final residual = 3.5740577e12, No Iterations 0 Min/max T:min(T) [0 0 0 1 0 0 0] 300 max(T) [0 0 0 1 0 0 0] 317.42429 ExecutionTime = 48517.93 s ClockTime = 49700 s Region: fluid Courant Number mean: 0.019875723 max: 0.29875153 Region: fibrothal_in Diffusion Number mean: 5.3693123e08 max: 3.8684525e07 Region: solid_bricks Diffusion Number mean: 2.453461e06 max: 1.317393e05 Region: unifrax_out Diffusion Number mean: 1.0442085e07 max: 3.2171136e07 deltaT = 0.0011417394 Time = 132.8413 Solving for fluid region fluid diagonal: Solving for rho, Initial residual = 0, Final residual = 0, No Iterations 0 DILUPBiCG: Solving for Ux, Initial residual = 7.8970139e05, Final residual = 2.3571827e08, No Iterations 1 DILUPBiCG: Solving for Uy, Initial residual = 6.0058436e05, Final residual = 2.2336877e08, No Iterations 1 DILUPBiCG: Solving for Uz, Initial residual = 8.2795778e05, Final residual = 1.7421106e08, No Iterations 1 DILUPBiCG: Solving for h, Initial residual = 1.3770425e05, Final residual = 1.8043668e09, No Iterations 1 Min/max T:35.535871 939 GAMG: Solving for p_rgh, Initial residual = 0.0041525003, Final residual = 8.3978618e08, No Iterations 16 GAMG: Solving for p_rgh, Initial residual = 2.0716891e05, Final residual = 8.414588e08, No Iterations 6 GAMG: Solving for p_rgh, Initial residual = 5.9691193e06, Final residual = 6.361722e08, No Iterations 4 diagonal: Solving for rho, Initial residual = 0, Final residual = 0, No Iterations 0 time step continuity errors (fluid): sum local = 5.2482977e11, global = 1.8655448e12, cumulative = 1.0816265e07 GAMG: Solving for p_rgh, Initial residual = 1.6250719e06, Final residual = 7.813847e08, No Iterations 2 GAMG: Solving for p_rgh, Initial residual = 4.7865432e07, Final residual = 6.8283963e08, No Iterations 1 GAMG: Solving for p_rgh, Initial residual = 1.8631846e07, Final residual = 3.5284387e08, No Iterations 1 diagonal: Solving for rho, Initial residual = 0, Final residual = 0, No Iterations 0 time step continuity errors (fluid): sum local = 2.9109187e11, global = 2.3103795e13, cumulative = 1.0816242e07 Solving for solid region fibrothal_in DICPCG: Solving for h, Initial residual = 4.8424178e06, Final residual = 5.6627448e12, No Iterations 1 DICPCG: Solving for h, Initial residual = 7.5644313e12, Final residual = 7.5644313e12, No Iterations 0 Min/max T:min(T) [0 0 0 1 0 0 0] 35.538367 max(T) [0 0 0 1 0 0 0] 823.55579 Solving for solid region solid_bricks DICPCG: Solving for h, Initial residual = 5.3879905e06, Final residual = 1.864035e10, No Iterations 1 DICPCG: Solving for h, Initial residual = 1.9767345e10, Final residual = 1.9767345e10, No Iterations 0 Min/max T:min(T) [0 0 0 1 0 0 0] 300.00584 max(T) [0 0 0 1 0 0 0] 390.08076 Solving for solid region unifrax_out DICPCG: Solving for h, Initial residual = 3.1119927e06, Final residual = 3.4747675e12, No Iterations 1 DICPCG: Solving for h, Initial residual = 3.5731187e12, Final residual = 3.5731187e12, No Iterations 0 Min/max T:min(T) [0 0 0 1 0 0 0] 300 max(T) [0 0 0 1 0 0 0] 317.42467 ExecutionTime = 48518.51 s ClockTime = 49700 s Region: fluid Courant Number mean: 0.019875633 max: 0.29874413 Region: fibrothal_in Diffusion Number mean: 5.3693195e08 max: 3.8684734e07 Region: solid_bricks Diffusion Number mean: 2.453461e06 max: 1.317393e05 Region: unifrax_out Diffusion Number mean: 1.0442085e07 max: 3.2171136e07 deltaT = 0.0011417394 Baran 

September 1, 2015, 19:37 

#9 
Senior Member
Alex
Join Date: Oct 2013
Posts: 337
Rep Power: 20 
Ok baran,
I guess that you are still using externalWallHeatFluxTemperature BC... If so, update your source code with the latest patches and corrections (in case you haven't done it for the last 3 months or so... If you installed OF 2.4.x less than 3 months ago it shouldn't be necessary...). Once you have uploaded it and recompiled it try using a similar specification for external boundaries to this one: Code:
myPatch { type externalWallHeatFluxTemperature; kappa fluidThermo; q uniform 1000; Ta uniform 300.0; h uniform 10.0; thicknessLayers (0.1 0.2 0.3 0.4); kappaLayers (1 2 3 4); value uniform 300.0; kappaName none; Qr Qr; relaxation 1; // try with lower values, using 1 will make no difference. Maybe 0.1 would do the trick... } Hope it helps. Best regards, Alex
__________________
Web site where I present my Master's Thesis: foamingtime.wordpress.com The case I talk about in this site was solved with chtMultiRegionSimpleFoam solver and involves radiation. Some basic tutorials are also resolved step by step in the web. If you are interested in these matters, you are invited to come in! 

September 4, 2015, 08:31 

#10 
Member
baran
Join Date: Aug 2014
Posts: 45
Rep Power: 10 
Dear Alex,
I have changed the outer wall bc of externalWallHeatFluxTemperature as it is already available in of2.4 ... Code:
{ type externalWallHeatFluxTemperature; kappa solidThermo; //q uniform 1000; Ta uniform 300.0; h uniform 10.0; //thicknessLayers (0.1 0.2 0.3 0.4); //kappaLayers (1 2 3 4); value uniform 300.0; kappaName none; Qr Qr; relaxation 1; } fvSolution... Code:
solvers { h { solver PCG; preconditioner DIC; tolerance 1e06; relTol 0.1; } hFinal { $h; tolerance 1e06; relTol 0; } } PIMPLE { nNonOrthogonalCorrectors 2; } Code:
ddtSchemes { default Euler; } gradSchemes { default Gauss linear; } divSchemes { default none; } laplacianSchemes { default none; laplacian(alpha,h) Gauss linear limited 0.333; } interpolationSchemes { default linear; } snGradSchemes { default limited 0.333; } fluxRequired { default no; } Code:
Region: fluid Courant Number mean: 0.011803868 max: 0.29978066 Region: fibrothal_in Diffusion Number mean: 5.984852e08 max: 3.6395751e07 Region: solid_bricks Diffusion Number mean: 4.325115e08 max: 2.3223831e07 Region: unifrax_out Diffusion Number mean: 1.2271976e07 max: 3.7808866e07 deltaT = 0.00134182 Time = 61.349217 Solving for fluid region fluid diagonal: Solving for rho, Initial residual = 0, Final residual = 0, No Iterations 0 DILUPBiCG: Solving for Ux, Initial residual = 0.00020252946, Final residual = 1.0480067e08, No Iterations 2 DILUPBiCG: Solving for Uy, Initial residual = 0.00022700634, Final residual = 4.9277215e09, No Iterations 2 DILUPBiCG: Solving for Uz, Initial residual = 0.00021673457, Final residual = 8.2935081e09, No Iterations 2 DILUPBiCG: Solving for h, Initial residual = 7.0113698e05, Final residual = 5.4885426e10, No Iterations 2 Min/max T:314.12367 753 GAMG: Solving for p_rgh, Initial residual = 0.0011703758, Final residual = 8.8669323e08, No Iterations 6 GAMG: Solving for p_rgh, Initial residual = 4.657791e06, Final residual = 5.7582968e08, No Iterations 3 GAMG: Solving for p_rgh, Initial residual = 1.1551078e06, Final residual = 4.3470744e08, No Iterations 2 diagonal: Solving for rho, Initial residual = 0, Final residual = 0, No Iterations 0 time step continuity errors (fluid): sum local = 3.9981212e10, global = 2.0513208e11, cumulative = 1.7388678e08 GAMG: Solving for p_rgh, Initial residual = 1.3509646e06, Final residual = 7.2930855e08, No Iterations 2 GAMG: Solving for p_rgh, Initial residual = 2.5230028e07, Final residual = 5.9736719e08, No Iterations 1 GAMG: Solving for p_rgh, Initial residual = 1.1260898e07, Final residual = 4.3606164e08, No Iterations 1 diagonal: Solving for rho, Initial residual = 0, Final residual = 0, No Iterations 0 time step continuity errors (fluid): sum local = 4.0105979e10, global = 3.4002934e11, cumulative = 1.7422681e08 Solving for solid region fibrothal_in DICPCG: Solving for h, Initial residual = 1.3847821e05, Final residual = 1.3047331e11, No Iterations 1 DICPCG: Solving for h, Initial residual = 1.3725991e11, Final residual = 1.3725991e11, No Iterations 0 DICPCG: Solving for h, Initial residual = 1.3725991e11, Final residual = 1.3725991e11, No Iterations 0 Min/max T:min(T) [0 0 0 1 0 0 0] 300 max(T) [0 0 0 1 0 0 0] 611.48428 Solving for solid region solid_bricks DICPCG: Solving for h, Initial residual = 1.0430615e05, Final residual = 6.5189609e12, No Iterations 1 DICPCG: Solving for h, Initial residual = 9.8068229e12, Final residual = 9.8068229e12, No Iterations 0 DICPCG: Solving for h, Initial residual = 9.8068229e12, Final residual = 9.8068229e12, No Iterations 0 Min/max T:min(T) [0 0 0 1 0 0 0] 300 max(T) [0 0 0 1 0 0 0] 666.81513 Solving for solid region unifrax_out DICPCG: Solving for h, Initial residual = 2.4035529e05, Final residual = 1.605035e11, No Iterations 1 DICPCG: Solving for h, Initial residual = 1.544039e09, Final residual = 1.544039e09, No Iterations 0 DICPCG: Solving for h, Initial residual = 1.544039e09, Final residual = 1.544039e09, No Iterations 0 Min/max T:min(T) [0 0 0 1 0 0 0] 300 max(T) [0 0 0 1 0 0 0] 300.03595 ExecutionTime = 16126.77 s ClockTime = 16559 s Region: fluid Courant Number mean: 0.011803874 max: 0.29977296 Region: fibrothal_in Diffusion Number mean: 5.9848554e08 max: 3.6395834e07 Region: solid_bricks Diffusion Number mean: 4.325115e08 max: 2.3223831e07 Region: unifrax_out Diffusion Number mean: 1.2271976e07 max: 3.7808866e07 deltaT = 0.00134182 Time = 61.350559 Solving for fluid region fluid diagonal: Solving for rho, Initial residual = 0, Final residual = 0, No Iterations 0 DILUPBiCG: Solving for Ux, Initial residual = 0.0002025609, Final residual = 1.1910169e08, No Iterations 2 DILUPBiCG: Solving for Uy, Initial residual = 0.00022700465, Final residual = 4.884998e09, No Iterations 2 DILUPBiCG: Solving for Uz, Initial residual = 0.00021670343, Final residual = 8.4535848e09, No Iterations 2 DILUPBiCG: Solving for h, Initial residual = 7.0106796e05, Final residual = 5.5296829e10, No Iterations 2 LU Back substitute C matrix.. Min/max T:314.12101 753 GAMG: Solving for p_rgh, Initial residual = 0.0011700388, Final residual = 7.9481395e08, No Iterations 6 GAMG: Solving for p_rgh, Initial residual = 4.6523857e06, Final residual = 5.1471481e08, No Iterations 3 GAMG: Solving for p_rgh, Initial residual = 1.1486924e06, Final residual = 4.0637e08, No Iterations 2 diagonal: Solving for rho, Initial residual = 0, Final residual = 0, No Iterations 0 time step continuity errors (fluid): sum local = 3.7375369e10, global = 4.3799329e12, cumulative = 1.7427061e08 GAMG: Solving for p_rgh, Initial residual = 1.3509856e06, Final residual = 6.9778436e08, No Iterations 2 GAMG: Solving for p_rgh, Initial residual = 2.5777917e07, Final residual = 5.2959357e08, No Iterations 1 GAMG: Solving for p_rgh, Initial residual = 1.065836e07, Final residual = 3.6159249e08, No Iterations 1 diagonal: Solving for rho, Initial residual = 0, Final residual = 0, No Iterations 0 time step continuity errors (fluid): sum local = 3.3257513e10, global = 3.1279595e11, cumulative = 1.745834e08 Solving for solid region fibrothal_in DICPCG: Solving for h, Initial residual = 1.3848359e05, Final residual = 1.3046006e11, No Iterations 1 DICPCG: Solving for h, Initial residual = 1.5699743e11, Final residual = 1.5699743e11, No Iterations 0 DICPCG: Solving for h, Initial residual = 1.5699743e11, Final residual = 1.5699743e11, No Iterations 0 Min/max T:min(T) [0 0 0 1 0 0 0] 300 max(T) [0 0 0 1 0 0 0] 611.4786 Solving for solid region solid_bricks DICPCG: Solving for h, Initial residual = 1.0418483e05, Final residual = 6.5202524e12, No Iterations 1 DICPCG: Solving for h, Initial residual = 2.4807543e09, Final residual = 2.4807543e09, No Iterations 0 DICPCG: Solving for h, Initial residual = 2.4807543e09, Final residual = 2.4807543e09, No Iterations 0 Min/max T:min(T) [0 0 0 1 0 0 0] 289.72511 max(T) [0 0 0 1 0 0 0] 649.88563 Solving for solid region unifrax_out DICPCG: Solving for h, Initial residual = 2.4034686e05, Final residual = 1.6049802e11, No Iterations 1 DICPCG: Solving for h, Initial residual = 1.6219618e09, Final residual = 1.6219618e09, No Iterations 0 DICPCG: Solving for h, Initial residual = 1.6219618e09, Final residual = 1.6219618e09, No Iterations 0 Min/max T:min(T) [0 0 0 1 0 0 0] 300 max(T) [0 0 0 1 0 0 0] 300.03596 ExecutionTime = 16127.5 s ClockTime = 16560 s Region: fluid Courant Number mean: 0.011803878 max: 0.29976523 Region: fibrothal_in Diffusion Number mean: 5.9848588e08 max: 3.6395917e07 Region: solid_bricks Diffusion Number mean: 4.325115e08 max: 2.3223831e07 Region: unifrax_out Diffusion Number mean: 1.2271976e07 max: 3.7808866e07 deltaT = 0.00134182 Time = 61.351901 Solving for fluid region fluid diagonal: Solving for rho, Initial residual = 0, Final residual = 0, No Iterations 0 DILUPBiCG: Solving for Ux, Initial residual = 0.000202575, Final residual = 1.1953834e08, No Iterations 2 DILUPBiCG: Solving for Uy, Initial residual = 0.00022699901, Final residual = 4.9589681e09, No Iterations 2 DILUPBiCG: Solving for Uz, Initial residual = 0.00021670665, Final residual = 8.6043666e09, No Iterations 2 DILUPBiCG: Solving for h, Initial residual = 7.0163301e05, Final residual = 5.5663264e10, No Iterations 2 Min/max T:289.72512 753 GAMG: Solving for p_rgh, Initial residual = 0.0011745932, Final residual = 9.461503e08, No Iterations 23 GAMG: Solving for p_rgh, Initial residual = 1.3703751e05, Final residual = 9.2266387e08, No Iterations 5 GAMG: Solving for p_rgh, Initial residual = 3.2030153e06, Final residual = 7.2234752e08, No Iterations 3 diagonal: Solving for rho, Initial residual = 0, Final residual = 0, No Iterations 0 time step continuity errors (fluid): sum local = 6.6436148e10, global = 1.1345981e10, cumulative = 1.75718e08 GAMG: Solving for p_rgh, Initial residual = 2.1936572e06, Final residual = 7.8329574e08, No Iterations 3 GAMG: Solving for p_rgh, Initial residual = 5.4352731e07, Final residual = 9.250977e08, No Iterations 1 GAMG: Solving for p_rgh, Initial residual = 2.3308027e07, Final residual = 5.8853582e08, No Iterations 1 diagonal: Solving for rho, Initial residual = 0, Final residual = 0, No Iterations 0 time step continuity errors (fluid): sum local = 5.4130436e10, global = 5.585416e11, cumulative = 1.7515946e08 Solving for solid region fibrothal_in DICPCG: Solving for h, Initial residual = 1.3847885e05, Final residual = 1.3045515e11, No Iterations 1 DICPCG: Solving for h, Initial residual = 1.3991418e11, Final residual = 1.3991418e11, No Iterations 0 DICPCG: Solving for h, Initial residual = 1.3991418e11, Final residual = 1.3991418e11, No Iterations 0 Min/max T:min(T) [0 0 0 1 0 0 0] 300 max(T) [0 0 0 1 0 0 0] 611.48274 Solving for solid region solid_bricks DICPCG: Solving for h, Initial residual = 1.0418394e05, Final residual = 6.519972e12, No Iterations 1 DICPCG: Solving for h, Initial residual = 9.8457579e12, Final residual = 9.8457579e12, No Iterations 0 DICPCG: Solving for h, Initial residual = 9.8457579e12, Final residual = 9.8457579e12, No Iterations 0 Min/max T:min(T) [0 0 0 1 0 0 0] 289.71756 max(T) [0 0 0 1 0 0 0] 649.89343 Solving for solid region unifrax_out DICPCG: Solving for h, Initial residual = 2.4034443e05, Final residual = 1.6049873e11, No Iterations 1 DICPCG: Solving for h, Initial residual = 1.6956056e09, Final residual = 1.6956056e09, No Iterations 0 DICPCG: Solving for h, Initial residual = 1.6956056e09, Final residual = 1.6956056e09, No Iterations 0 Min/max T:min(T) [0 0 0 1 0 0 0] 300 max(T) [0 0 0 1 0 0 0] 300.03596 ExecutionTime = 16127.98 s ClockTime = 16561 s I can't understand why suddenly there is low temperature in solid_bricks....please suggest something... Regards, Baran 

December 17, 2019, 18:36 

#11 
New Member
Dániel Bakonyi
Join Date: Dec 2019
Location: Budapest, Hungary
Posts: 2
Rep Power: 0 
Dear all,
I am currenlty facing what seems to be the same problem. I am using OF 7 and chtMultiRegionFoam and I am trying to simulate the inside of a furnace where a bunch of solid pans are stacked on each other. My setup is steadyState and it runs just fine without radiation. My settings are based mostly on the OF6 MultiRegionHeaterRadiation tutorial. However, as soon as I introduce radiation to the model it crashes in a few iterations with the a negative initial temperature error, or because the max number of iterations is exceeded by the h solver (if I try to constarin T with limitTemperature in the solid). fluid region thermal and radiation properties: Code:
thermoType { type heRhoThermo; mixture pureMixture; transport polynomial; thermo hPolynomial; equationOfState icoPolynomial; specie specie; energy sensibleEnthalpy; } ... radiation on; riadaitionModel P1; solverFreq 1; absorptionEmissionModel constant; constantCoeffs { absorptivity 0.07; emissivity 0.037; E 0; } scatterModel none; sootModel none; Code:
thermoType { type heSolidThermo; mixture pureMixture; transport constIso; thermo hConst; equationOfState rhoConst; specie specie; energy sensibleEnthalpy; } mixture { specie { molWeight 28; } equationOfState { rho 1380; } transport { kappa 1; } thermodynamics { Hf 0; Cp 900; } } ... radiation on; radiationModel opaqueSolid; absorptionEmissionModel constant; constantCoeffs { absorptivity 0; emissivity 0.9; E 0; } Code:
ddtSchemes { default steadyState; } gradSchemes { default Gauss linear; } divSchemes { default none; div(phi,U) bounded Gauss upwind; div(phi,h) bounded Gauss upwind; div(phi,epsilon) bounded Gauss upwind; div(phi,k) bounded Gauss upwind; div(phi,K) bounded Gauss linear; div(phiv,p) Gauss upwind; div(((rho*nuEff)*dev2(T(grad(U))))) Gauss linear; } laplacianSchemes { default Gauss linear uncorrected; } interpolationSchemes { default linear; } snGradSchemes { default uncorrected; } ... solvers { ... "G.*" { solver PCG; preconditioner DIC; tolerance 1e5; relTol 0.1; } ... } relaxationFactors { fields { "rho.*" 1.0; "p_rgh.*" 0.7; } equations { "U.*" 0.3; "h.*" 0.7; "k.*" 0.7; "epsilon.*" 0.7; "G" 0.7; } } Code:
ddtSchemes { default steadyState; } gradSchemes { default Gauss linear; } divSchemes { default none; } laplacianSchemes { default none; laplacian(alpha,h) Gauss linear uncorrected; } interpolationSchemes { default linear; } snGradSchemes { default uncorrected; } Code:
//T BC for the extrenal walls of the furnace { type externalWallHeatFluxTemperature; mode coefficient; h uniform 8; Ta constant 1000; value $internalField; kappaLayers (0.5); thicknessLayers (0.25); kappaMethod fluidThermo; qr qr; } //T BC for the faces of the solid regions in the middle of the fluid { type compressible::turbulentTemperatureRadCoupledMixed; Tnbr T; kappaMethod fluidThermo; qrNbr none; qr qr; value $internalField; } //G for the external walls { type MarshakRadiation; emissivityMode lookup; emissivity uniform 0.9; value $internalField; } //G for the internal walls { type MarshakRadiation; emissivityMode solidRadiation; emissivity uniform 0.9; value $internalField; } Code:
{ type compressible::turbulentTemperatureRadCoupledMixed; Tnbr T; kappaMethod solidThermo; qrNbr qr; qr none; value $internalField; } I checked the results with ParaView as suggested earlier in this thred. Everything is fine before the radiation is added and then the problem is with the solid region not with the extrenal walls. When I plot the temperature for the surface_to_fluid patches they start to diverge in the negative direction from the temperature in the fluid_to_solid patches at the same place. the r field plotted on the same surafces is negative where this happens. https://app.box.com/s/bhz1wlgcgt3iobxfnnuu35z5poibi0hk https://app.box.com/s/rqgmuf541vw8ta88fnqftcipjquwfxdg and finally the temprature gets negative in the edges of the solid region before everything goes to hell: https://app.box.com/s/8mwikreoznywcdtnnayjrh3175lttehs The solid regions is loosing thermal energy and I dont know why. I have read several of zfaraday's posts about radiation modeling but there is no relaxation option for the turbuelntTemepratureRadCoupledMixed bc that I can find. Is there something obviously wrong in my setup? I am completely stuck, so any help would be greatly appreciated! Dear Baran, I know it has been quite a while, but have you found asolution for your problem? Last edited by Daniel Bakonyi; December 18, 2019 at 08:30. 

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