Heat transfer coefficient for convection

Heat transfer coefficient for convection in channel acc. Heinhold eq. 18.18 to 18.20

Symbol
$\alpha_{sa}$
Unit
W/K/m$^2$
Formulae
$1.08 k_{sa_{2}} \left(\frac{\Delta \theta_{s}}{D_{o} k_{sa}}\right)^{0.25} + \frac{0.0185 k_{sa_{1}}}{D_{o} k_{sa}}$
Related
$D_{o}$