convection heat transfer coefficient

[etorres]

Hi all,
I want to evaluate convection heat loss for a short cylinder but all correlations are said to be valid for long cylinder (Churchill and Chu, etc). Does anybody know to what extent a cylinder can be considered short or long and so typical correlations can provide a goog estimation for it?
Thanks in advance

 

[abeltio]

i would consider long if L/D>20 and 2D away from the ends...



saludos.
a.