Experiments have been conducted to determine local heat transfer coefficients for flow perpendicular to a long, isothermal

Question:

Experiments have been conducted to determine local heat transfer coefficients for flow perpendicular to a long, isothermal bar of rectangular cross section. The bar is of width c, parallel to the flow, and height d, normal to the flow. For Reynolds numbers in the range 104

Nu = hd Ik = CRe, Pr3 Face cld Front 0.674 0.33 < cld s 1.33 1/2 Side 0.33 0.153 2/3 Side 1.33 0.107 2/3 Back 0.33 0.174

Determine the value of the average heat transfer coefficient for the entire exposed surface (that is, averaged over all four faces) of a c = 40-mm wide, d = 30-mrn tall rectangular rod. The rod is exposed to air in Cross-flow at V = 10 m/s, T∞ = 300 K. Provide a plausible explanation of the relative values of the face-averaged heat transfer coefficients on the front side and back faces.