Convective Heat Transfer

[ysg519]

I am setting up a convective heat transfer interaction in abaqus. My model has a flat Alumina surface at a certain temperature (greater than ambient temp) exposed to atmosphere. I am not sure as to
1. what value to input for the Film Coeffecient (Flat Alumina surface)
2. What expression should I use in the Expression Field. Is this expression merely the direction in which the convection takes place? Please help. Thanks

 

[ysg519]

I have come across the convective heat transfer coeff value for air as between 10 - 100 (W/m2K) . That range seems like a big range any ideas as to how to narrow down that range?

 

[corus]

There are simplified expression for natural convection to air from vertical and horizontal surfaces but these are related to the delta T to the power 0.25 or 0.333. It's better if you can put these temperature dependent values in as a table rather than as a subroutine, but either way is acceptable. For horizontal plates facing upwards the expression is h=0.38 x delta T^0.25 (see McAdams)

corus