Question

A long cylindrical black surface fuel rod of diameter 25 mm is shielded by a surface concentric to the rod. The shield has diameter of 50 mm, and its outer surface is exposed to surrounding air at 300 K with a convection heat transfer coefficient of 15 W/m2.K. Inner and outer surfaces of the shield have an emissivity of 0.05, and the gap between the fuel rod and the shield is a vacuum. If the shield maintains a uniform temperature of 335 K, determine the surface temperature of the fuel rod

Answer 1

surface temp of fuel rod = 678.85 K

Step-by-step explanation:

Given data :

D1 = 25 mm

D2 = 50 mm

T2 = 335 k

T∞ = 300 k

hconv = 0.15 w/m^2.k

ε2 = 0.05

ε1 = 1

Determine energy at Q23

Q23 = Qconv + Qrad

attached below is the detailed solution

Insert given values into equation 1 attached below to obtain the surface temperature of the fuel rod ( T1 )