In a pilot plant, a viscous oil is being cooled from 200 to 110°C in a 1.0-in. jacketed pipe with water flowing in the jacket at an average temperature of 30°C. To get greater cooling of the oil, it has been suggested that the exchanger be replaced with one having a greater inside diameter (1.5 in.) but the same length. 

(a) If the oil is in laminar flow in the 1.0-in. pipe, what change in exit temperature might result from using the larger exchanger? 

(b) Repeat part (a), assuming the oil is in turbulent flow.