Is a Convection Coefficient of 37 Indicative of Free Convection?

[3wash]

Dear all

I got a value of 37 for h ( convection heat transfer )

Does it consider as free or natural convection heat transfer coefficient?

Thanks in advance !

And Sorry its not a Homework problem :)

 

[RTW69]

What is the application. English or SI units. More information would be helpful.

 

[Mech_Engineer]

Your question is difficult to answer without more informtation, but as a general rule free convection is driven by differential density due temperature difference in a fluid and forced convection is driven by some external means (for example a fan).

 

[chaos_zzy]

For nature convection heat transfer coefficient h =10w/m^2-k(including radiation)
For force convection, h range is more large, however you can take 25w/m^2-k for coarse estimate.

 

[Mech_Engineer]

For nature convection heat transfer coefficient h =10w/m^2-k(including radiation)
For force convection, h range is more large, however you can take 25w/m^2-k for coarse estimate.

Where exactly do these estimates come from? Without citing a source they're gibbereish and can't be used; especially since they don't take into account anything regarding fluid properties, geometry, etc.

 

[chaos_zzy]

Thanks for Mech's remind. The listed value is for air cooling.
Acctually the precise h value needs detailed information such as shape, fluid, ambient condition. Normally i use CFD software to calculate.
However, the listed value can be used for draft esimated and may answer the raised question.