B) In a shell-and-tube heat exchanger, 10000 kg/h water flowing in the pipes is heated from 16C to 84C by means of the hot machine oil flowing by the casing. The oil enters the body in a single pass at a temperature of 160 C and exits at a temperature of 94 C. The average heat transfer coefficient of the oil is 400 W/m2K. The water flows in 11 brass pipes with an inner diameter of 22.9 mm and an outer diameter of 25.4 mm, and each pipe makes four passes in the body. Assuming fully developed flow for water flow, find the required pipe length in one pass? (at 400 K temperature for brass: k=137 W/mK, for water: 323 K temperature =998,1 kg/m3 , k=0,643 W/mK, cp=4182 J/kgK, =548x10-6 Pa.s, Pr=3,56)