Question

The wall of a furnace consists of
a sheet metal (em=3 mm, km=14
W/mK), an insulator (eisn=3 cm, kins=0.5
W/mK) and another sheet metal like the
first. If the interior temperature is
250ºC and the ambient temperature 25ºC, calculate the
power dissipated to the outside and the
temperature of the internal plate when the
emissivity of the inner surface is
0.9, the inner film coefficient 15
W/m2K and the temperature of the sheet
external 42ºC

Answer 1

First,by FOURIERS law find power dissipated using formula of conduction in slab

then by using formula of NEWTONS cooling law find temp of inner plate