I am trying to simulate a cubesat subsystem and I made a simplified model to start with. Is made by two separate meshes, the first representing the solar panel, and the second the subsystem. Solar panel receiving, radiation from the sun and radiates out the energy. Part of the energy is radiated in the subsystem. In the real scenario the subsystem will be covers with panels from every direction plus there are fluxes on the other sides too (reflection from earth surface and earth's IR radiation), and some heat generation from the subsystem components. the system is as follows:

The sun radiation boundary condition is applied in this surface

And the radiation is "coming out" from those surfaces

Heat equation is:

Code: Select all

```
Solver 1
Equation = Heat Equation
Procedure = "HeatSolve" "HeatSolver"
Variable = Temperature
Exec Solver = Always
Stabilize = True
Bubbles = False
Lumped Mass Matrix = False
Optimize Bandwidth = True
Steady State Convergence Tolerance = 1.0e-5
Nonlinear System Convergence Tolerance = 1.0e-7
Nonlinear System Max Iterations = 20
Nonlinear System Newton After Iterations = 3
Nonlinear System Newton After Tolerance = 1.0e-3
Nonlinear System Relaxation Factor = 1
Linear System Solver = Iterative
Linear System Iterative Method = BiCGStab
Linear System Max Iterations = 500
Linear System Convergence Tolerance = 1.0e-10
BiCGstabl polynomial degree = 2
Linear System Preconditioning = ILU0
Linear System ILUT Tolerance = 1.0e-3
Linear System Abort Not Converged = False
Linear System Residual Output = 10
Linear System Precondition Recompute = 1
End
```

And the two boundary conditions:

Code: Select all

```
Boundary Condition 1
Target Boundaries(1) = 8
Name = "Flux"
Heat Flux = 100
End
```

Code: Select all

```
Boundary Condition 2
Target Boundaries(3) = 3 4 7
Name = "Radiation"
Radiation Boundary Open = True
Radiation = Diffuse Gray
External Temperature = 100
Emissivity = 0.8
End
```

Code: Select all

```
RadiationFactors: Computing radiation factors for heat transfer
RadiationFactors: ----------------------------------------------------
RadiationFactors: Total number of Radiation Surfaces 3834 out of 5856
RadiationFactors: Computing factors...
RadiationFactors: View factors filling (%) 2.2434E+01
RadiationFactors: Solution: 26 % done
RadiationFactors: Solution: 65 % done
RadiationFactors: Minimum Gebhardt factors sum 0.0000E+00
RadiationFactors: Maximum Gebhardt factors sum 4.0921E-01
RadiationFactors: Maximum share of omitted factors 0.0000E+00
RadiationFactors: Gebhardt factors filling (%) 4.4828E+01
RadiationFactors: Gebhardt factors determined (s) 3.3956E+01
RadiationFactors: All done time (s) 3.3956E+01
RadiationFactors: ----------------------------------------------------
malloc(): invalid size (unsorted)
Program received signal SIGABRT: Process abort signal.
Backtrace for this error:
#0 0x7fafe57b2cb1 in ???
#1 0x7fafe57b1e75 in ???
#2 0x7fafe55e846f in ???
#3 0x7fafe55e83eb in ???
#4 0x7fafe55c7898 in ???
#5 0x7fafe563238d in ???
#6 0x7fafe563a4db in ???
#7 0x7fafe563d283 in ???
#8 0x7fafe563f448 in ???
#9 0x7fafe5bac4e5 in __listmatrix_MOD_list_getmatrixentry
at /home/streamserver/Documents/elmerfem/fem/src/ListMatrix.F90:476
#10 0x7fafe5bac6fe in __listmatrix_MOD_list_addmatrixindexes
at /home/streamserver/Documents/elmerfem/fem/src/ListMatrix.F90:456
#11 0x7fafe5c19561 in __elementutils_MOD_makelistmatrix
at /home/streamserver/Documents/elmerfem/fem/src/ElementUtils.F90:658
#12 0x7fafe5c1c14e in __elementutils_MOD_creatematrix
at /home/streamserver/Documents/elmerfem/fem/src/ElementUtils.F90:1646
#13 0x7fafe5cded0c in __mainutils_MOD_addequationbasics
at /home/streamserver/Documents/elmerfem/fem/src/MainUtils.F90:1513
#14 0x7fafe5ef8502 in addsolvers
at /home/streamserver/Documents/elmerfem/fem/src/ElmerSolver.F90:1105
#15 0x7fafe5f04331 in elmersolver_
at /home/streamserver/Documents/elmerfem/fem/src/ElmerSolver.F90:398
#16 0x563ddd60a3cd in solver
at /home/streamserver/Documents/elmerfem/fem/src/Solver.F90:57
#17 0x563ddd60a13e in main
at /home/streamserver/Documents/elmerfem/fem/src/Solver.F90:34
```

https://cloud.libre.space/s/CqnBnoPdzfzHdpg

Thanks in advance