Consider using the experimental methodology of Problem 4.70 to determine the convection coefficient distribution about an airfoil of complex shape.

Accounting for conduction in the metal sheathing and radiation losses to the large surroundings, determine the convection heat transfer coefficients at the locations shown. The surface locations at which the temperatures are measured are spaced 2 mm apart. The thickness of the metal sheathing is t = 20 μm, the volumetric generation rate is q20 X 10⁶ W/m³, the sheathing’s thermal conductivity is k = 25 W/m
· K, and the emissivity of the painted surface is ε = 0.98. Compare your results to cases where (i) both conduction along the sheathing and radiation are neglected, and (ii) when only radiation is neglected.

Data From Problem 4.70

Consider Problem 4.69. An engineer desires to measure  the surface temperature of the thin sheathing by painting  it black (ε = 0.98) and using an infrared measurement device to nonintrusively determine the surface temperature distribution. Predict the temperature distribution of the painted surface, accounting for radiation heat transfer with large surroundings at T_sur = 25C.

Transcribed Image Text:

Air T = 25°C 2 30 Tsur = 25°C 5 6 7 8 9 10 11 12 13. 14 Insulation 15 28 27 26 25 24 23 22 21 20 19 18 17 29 Metal sheathing 16