Consider air flowing in a small-diameter steel tube. Graph the Nusselt number associated with fully devel- oped laminar flow with constant surface heat flux for tube diameters ranging from 1 µ,m D 1 mm. Evaluate air properties at T = 350 K and atmospheric pressure. The thermal and momentum accommodation coefficients are at = 0.92 and ap = 0.87, respectively. Compare the Nusselt number you calculate to the value provided in Equation 8.53, NuD = 4.36.