Discuss the following:
Q: A very thick slab with thermal diffusivity 5.6 x 10-6 m2/s and thermal conductivity 20 W/m · K is initially at a uniform temperature of 325°C. Suddenly, the surface is exposed to a coolant at 15°C for which the convection heat transfer coefficient is 100 W/m2 · K.
(a) Determine temperatures at the surface and at a depth of 45 mm after 3 min have elapsed.
(b) Compute and plot temperature histories (0 < t="">< 300="" s)="" at="" x="0" and="" x="45" mm="" for="" the="" following="" parametric="" variations:="" (i)="" a="5.6" x="" 10-7,="" 5.6="" x="" 10-6,="" and="" 5.6="" x="" 10-5="" m2/s;="" and="" (ii)="" k="2," 20,="" and="" 200="" w/m="" ·="" k.="">