A small stirred tank used for batch crystallization of an antibiotic gave satisfactory results when the 10-cm turbine was operated at 550 r/min. The tank was 30 cm in diameter with an average depth of 40 cm, and contained four baffles. 

(a) What was the power input per unit volume for the small tank? (Give as kW/m³ and hp/100 gal.)

(b) What stirrer speed is needed for a similar tank 2 m in diameter if P/V is kept constant? 

(c) For constant P/V, what is the change in maximum shear rate on scaling up to the large tank?