A semi-infinite aluminium cylinder (k = 237 W/m K, = 9.71 10–6 m2/s) of diameter 20 cm is initially at a uniform temperature of 200°C. The cylinder is now placed in water at 15°C where heat transfer...

A semi-infinite aluminium cylinder (k = 237 W/m K,

= 9.71

10^–6
m²/s) of diameter 20 cm is initially at a uniform temperature of 200°C. The cylinder is now placed in water at 15°C where heat transfer takes place by convection with h = 120 W/m²
K. Determine the temperature at the centre of the cylinder 15 cm from the end surface 5 min after the start of cooling.