Chapter 1, Problem 1.43P

Heat is transferred by radiation and convection betweenthe inner surface of the nacelle of the wind turbine ofExample 1.3 and the outer surfaces of the gearbox andgenerator. The convection heat (lux associated withthe gearbox and the generator may be describedby ${q^{″}}_{conv.gb}=h\left(T_{gb}-T_{\infty }\right)$ and ${q^{″}}_{conv.gen}=h\left(T_{gen}-T_{\infty }\right)$ ,respectively, where the ambient temperature $T_{\infty }=T_s$ (which is the nacelle temperature) and $h=40\text{W}/{\text{m}}^{\text{2}}\cdot \text{K}$ .The outer surfaces of both the gearbox and the generatorare characterized by an emissivity of $\in \text{=0}\text{.9}$ . If the surface areas of the gearbox and generator are $A_{gb}=6{\text{m}}^2$ and $A_{gen}=4{\text{m}}^2$ , respectively, determine their surfacetemperatures.