Pb. 11.5 (O. Levenspiel)
The thermal properties of a sand pile are to be evaluated by quickly pouring a
bucketful of hot sand into a long 12-cm-i.d. aluminum pipe which is
immersed in water at 20 ºC. An axial thermocouple reads 140 ºC just after
the sand is poured in, 32 ºC after 100 min, and 25 ºC after 135 min.
From this information, evaluate the thermal conductivity and thermal
diffusivity of the sand pile.