A long 15 cm diameter shaft of stainless steel (K = 14.9 W/mK), ρ = 7900 kg/m3 C = 477 J/kgK and α = 3.95 × 10-6 m2/s is at a uniform temperature of 450 °C. The shaft is allowed to cool slowly in a chamber at 150°C with heat transfer coefficient of h = 85 W/m2K. Calculate the temperature (℃) at the end of 25 min after the cooling starts.
Use (θ0 = 0.49 at Bi-1 = 2.337 and Fo = 1.053) and (θ0 = 0.88 at Bi-1 = 4.672 and Fo = 1.053)Enter numerical value using the virtual keypad. Round off where necessary.