5. To reduce its viscosity, an oil is heated from 40C to 120C using a shell-and- tube heat exchanger. The oil flows in the shell at a rate of 83,000 kg h1 a) Using the information below, determine the number of tubes in this heat exchanger [3 marks) b) Calculate the ideal cross-flow heat transfer coefficient on the shell side. Use Appendix Q5 as well as the information given below. The viscosity correction may be ignored, so you may use the correlation Nu = ln Re Pr0.33 [17 marks) DATA Heat exchanger properties Exchanger design: U-tube Shell passes: 1 Total heat transfer area (outer surface area of all tubes combined): 312.0 m2 Tube length: 6.10 m Baffle type: segmented Shell inside diameter to baffle spacing ratio: 5 Tube outside diameter: 25.4 mm Tube pattern: square, with pitch-to-diameter ratio 1.25 Tube bundle diameter: 0.960 m Properties of the oil at 80C Density: 790 kg m Viscosity: 5.2 x 10-N m2 Specific heat capacity: 2070 J kg K1 Thermal conductivity: 0.14 W m-K-1 Total marks = 20