[hswzzz]

Hello,

I tried to simulate natural convection of water.

One of boundary conditions is 'heat flux'

//*****************************************//
object T;
dimensions [0 0 0 1 0 0 0];

internalField uniform 370.15;

boundaryField
{
heater
{
type compressible::turbulentHeatFluxTemperature;
heatSource flux;
q uniform 600000000;
kappa fluidThermo;
kappaName none;
Qr none;
value uniform 373.15;
}
...
}
//*****************************************//

Water properties are like below

FoamFile
{
version 2.0;
format ascii;
class dictionary;
location "constant";
object thermophysicalProperties.water;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

thermoType
{
type heRhoThermo;
mixture pureMixture;
transport const;
thermo hConst;
equationOfState perfectFluid;
specie specie;
energy sensibleEnthalpy;
}

mixture
{
specie
{
nMoles 1;
molWeight 18;
}
equationOfState
{
R 3000;
rho0 1027;
}
thermodynamics
{
Cp 4195;
Hf 0;
}
transport
{
mu 3.645e-04;
Pr 2.289;
}
}


When I check my log file .. the maximum and minimum rho is too high.
What can be the problem?



//*****************************************//
Time = 999

DILUPBiCG: Solving for h, Initial residual = 2.01931e-05, Final residual = 7.45851e-08, No Iterations 1
GAMG: Solving for p_rgh, Initial residual = 9.94268e-05, Final residual = 9.33105e-07, No Iterations 2
time step continuity errors : sum local = 0.000207754, global = -1.76408e-09, cumulative = -8.32725e-08
rho max/min : 2103.45 2012.94
DILUPBiCG: Solving for omega, Initial residual = 2.73581e-05, Final residual = 1.06548e-06, No Iterations 1
DILUPBiCG: Solving for k, Initial residual = 0.000215976, Final residual = 1.02418e-05, No Iterations 1
ExecutionTime = 4779.7 s ClockTime = 4813 s

Time = 1000

DILUPBiCG: Solving for h, Initial residual = 2.01858e-05, Final residual = 7.45415e-08, No Iterations 1
GAMG: Solving for p_rgh, Initial residual = 9.92196e-05, Final residual = 9.55777e-07, No Iterations 2
time step continuity errors : sum local = 0.000213729, global = -8.23112e-10, cumulative = -8.40956e-08
rho max/min : 2103.45 2012.94
DILUPBiCG: Solving for omega, Initial residual = 2.73423e-05, Final residual = 1.06513e-06, No Iterations 1
DILUPBiCG: Solving for k, Initial residual = 0.000215784, Final residual = 1.02308e-05, No Iterations 1
ExecutionTime = 4787.59 s ClockTime = 4821 s
//*****************************************//

[ssss]

You are using a heat flux of 600MW/m2, so the temperature should increase a lot and maybe there are some oscillations in the fields due to enormous gradient in the boundary, do you see any problem with paraFoam?

[hswzzz]

and my boundary condition..
- heater: heat flux 60kW/cm2 >> I will fix it
- bottom: zeroGradient
- side: zeroGradient
- top: *fixedValue 353K...(I think... there is energy inlet(heater), so need to energy out let)

[hswzzz]

I fixed the heat flux value. (600MW/m2 to 60kW/m2)
Rho value still is weird...

Starting time loop

Time = 1

DILUPBiCG: Solving for h, Initial residual = 0.999996, Final residual = 0.0168399, No Iterations 1
GAMG: Solving for p_rgh, Initial residual = 0.999993, Final residual = 0.00707171, No Iterations 6
time step continuity errors : sum local = 0.0283311, global = 9.8679e-16, cumulative = 9.8679e-16
rho max/min : 1027.09 1027.09
DILUPBiCG: Solving for omega, Initial residual = 1, Final residual = 0.000236418, No Iterations 1
DILUPBiCG: Solving for k, Initial residual = 1, Final residual = 0.00022971, No Iterations 1
ExecutionTime = 10.16 s ClockTime = 10 s

Time = 2

DILUPBiCG: Solving for h, Initial residual = 0.0798506, Final residual = 0.00138049, No Iterations 1
GAMG: Solving for p_rgh, Initial residual = 0.851577, Final residual = 0.00649395, No Iterations 6
time step continuity errors : sum local = 0.0526224, global = 6.31048e-11, cumulative = 6.31057e-11
rho max/min : 1951.39 1918.25
DILUPBiCG: Solving for omega, Initial residual = 0.29705, Final residual = 0.00455358, No Iterations 2
DILUPBiCG: Solving for k, Initial residual = 0.1462, Final residual = 0.00819619, No Iterations 1
ExecutionTime = 15.93 s ClockTime = 16 s

Time = 3

DILUPBiCG: Solving for h, Initial residual = 0.024874, Final residual = 0.000482555, No Iterations 1
GAMG: Solving for p_rgh, Initial residual = 0.753727, Final residual = 0.00524751, No Iterations 5
time step continuity errors : sum local = 0.017461, global = -5.93504e-11, cumulative = 3.75537e-12
rho max/min : 2043.82 2007.21
DILUPBiCG: Solving for omega, Initial residual = 0.177789, Final residual = 0.00253689, No Iterations 2
DILUPBiCG: Solving for k, Initial residual = 0.0855762, Final residual = 0.00619617, No Iterations 1
ExecutionTime = 21.43 s ClockTime = 22 s

Time = 4

DILUPBiCG: Solving for h, Initial residual = 0.0138778, Final residual = 0.000347565, No Iterations 1
GAMG: Solving for p_rgh, Initial residual = 0.416069, Final residual = 0.00284978, No Iterations 6
time step continuity errors : sum local = 0.00732328, global = -2.89873e-11, cumulative = -2.52319e-11
rho max/min : 2053.06 2016.06
DILUPBiCG: Solving for omega, Initial residual = 0.0994206, Final residual = 0.00140649, No Iterations 2
DILUPBiCG: Solving for k, Initial residual = 0.0575307, Final residual = 0.00440156, No Iterations 1
ExecutionTime = 27.11 s ClockTime = 28 s