A rod of diameter D = 25 mm and thermal conductivity of 60 W/m·Kprotrudes from a furnace with a wall temperature of 200ºC. The rodis welded to the furnace wall and is used as a hangar forinstrumentation cables. To avoid damaging the cables, the surfacetemperature of last 100 mm of the rod must be kept below 100ºC. Theambient air temperature is 25ºC and the convection coefficient is15 W/m2K. (a) Write the finite-difference equation for an internalnode with ?x = 2 mm. (b) Write the finite difference equation forthe node at the fin tip.
