[vigii]

Hi All,

I'm trying to assign heat flux to wall. Can anyone help me in defining the heatflux of 1000 W/m2 to wall.

Thanks in Advance.

Regards,
Vigii

[jishnuhari25]

You can give heat flux to wall by giving your wall patch name value as "fixedValue" instead of zeroGradient in Temperature 0-file. and then as value 1000/K;
K thermal conductivity of wall...Hope you got my point.For any further clarifications, your are alwayts welcome. I can help to my best

[jishnuhari25]

Somewhat like this::::::

wall
{
type fixedGradient;
value uniform xxxxxx;
}

xxxxxxx = 1000/thermal conductivity of the wall

[vigii]

Thanks for your help.

I have to define 1000 W/m2 flux on wall and K, thermal conductivity aluminum wall (205 W/mK) or Should I take thermal conductivity of air?.

If its aluminum, Then my temperature gradient is 1000/205?.

Regards,
Vigii

[rapierrz]

Hi vigii,

I think it's better that you implement wall temperature gradient with

groovyBC :

type groovyBC;

variables "q=1000;";

gradientExpression "q/K or q/oldTime(K)";

[rapierrz]

Originally Posted by vigii

Thanks for your help.

I have to define 1000 W/m2 flux on wall and K, thermal conductivity aluminum wall (205 W/mK) or Should I take thermal conductivity of air?.

If its aluminum, Then my temperature gradient is 1000/205?.

Regards,
Vigii

if your domain is a solid ,K is solid thermal conductivity;

if you want calculate the heat transfer coefficient near the wall that is fixed

you should take thermal conductivity of air.

see you want conduction or convection heat transfer.

[vigii]

Please look into the attached T File.

boundaryField
{
    topWall1
    {
        type            zeroGradient;
    }
	
    topWall2
    {
        type            zeroGradient;
    }

	roughWall
    {
	type 				fixedValue;
	value				uniform 4.8780;
    }
	
    bottomWall
    {
        type            zeroGradient;
    }

    inlet
    {
        type        	fixedValue;
        value      		uniform 292.15;
    }

    outlet
    {
        type            zeroGradient;
    }

    frontAndBackPlanes
    {
        type            empty;
    }
}

Please help me to assign Heat flux of 1000 W/m2 to roughWall.

[rapierrz]

if your K is fixed;

roughWall
{
type fixedGradient;
gradient uniform 1000/K;
}

if K is variable you must use of groovyBc.

[vigii]

This is not helping me.

[jherb]

Have a look at the turbluentHeatFluxTemperature boundary condition. (Do you have a turbulent flow inside your channel?)

https://github.com/OpenFOAM/OpenFOAM...luxTemperature

[jmdf]

You should specify in a better way what you intend to do.

Because if it's an external wall you use externalWallHeatFluxTemperature boundary and define a fixed heat flux. Link

If it's a non external wall, never tried it, but the suggestion from jherb should be a good solution.

Have a look at the turbluentHeatFluxTemperature boundary condition. (Do you have a turbulent flow inside your channel?)

https://github.com/OpenFOAM/OpenFOAM...luxTemperature

[calf.Z]

Originally Posted by jmdf

You should specify in a better way what you intend to do.

Because if it's an external wall you use externalWallHeatFluxTemperature boundary and define a fixed heat flux. Link

If it's a non external wall, never tried it, but the suggestion from jherb should be a good solution.

If kappa is not constant in fluid, should kappaMethod:fluidThermo be not suitable for constant heat flux q?