A 1200-W iron is left on the iron board with its base exposed to ambient air at 26°C. The base plate of the iron has a thickness of L = 0.5 cm, base area of A = 150 cm², and thermal conductivity of k = 18 W/m · K. The inner surface of the base plate is subjected to uniform heat flux generated by the resistance heaters inside. The outer surface of the base plate whose emissivity is ε = 0.7, loses heat by convection to ambient air with an average heat transfer coefficient of h = 30 W/m² · K as well as by radiation to the surrounding surfaces at an average temperature of T_surr = 295 K. Disregarding any heat loss through the upper part of the iron,

(a) Express the differential equation and the boundary conditions for steady one-dimensional heat conduction through the plate,

(b) Obtain a relation for the temperature of the outer surface of the plate by solving the differential equation,

(c) Evaluate the outer surface temperature.

Transcribed Image Text:

नि 0 Iron base plate L h 00 Tsurr X