Chapter 24, Problem 53P

For fluid flow over a surface, the heat flux to the surface can be computed as

$J=-k\frac{dT}{dy}$

Where $J=\text{heat flux }\left({\text{W/m}}^2\right)$, $k=\text{thermal conductivity }\left(\text{W/m}\cdot \text{K}\right)$, $T=\text{temperature }\left(\text{K}\right)$, and $y=\text{distance}$ normal to the surface (m). The following measurements are made for air flowing over a flat plate that is 200 cm long and 50 cm wide:

y, cm	0	1	3	5
T, K	900	480	270	200

If $k=0.028$ $\text{J/s}\cdot \text{m}\cdot \text{K}$, (a) determine the flux at the surface and (b) the heat transfer in watts. Note that $\text{1J}=\text{W }\cdot \text{s}$.