4) (45pts) Shell-and-Tube Heat Exchanger to Pasteurize Milk A shell-and-tube heat exchanger (1 shell pass, 4 tube passes) operated in counter-current mode is used to pasteurize liquid milk. Milk at 20C enters a 316 stainless steel tube (1/2",12 gage) at a volumetric flowrate of 6.0L/min. and must exit at 70C. The heating fluid is water which enters on the shell side at 100C and exits at 70C. The shell-side convective heat transfer coefficient (hshell) can be taken to be 500W/m2K. The overall heat transfer coefficient (U) mustbe calculated (not from a Table). The problem is to determine the required heat transfer area. Given: Properties: kss( stainless steel )=17.3W/mKhshell=500W/m2K Milk: The properties of milk can be taken as the same as those of water at the correct temperature. Tube: 1/2 inch, 12 gage tubing: i.d. =0.282(7.2103m); o.d. =0.5(1.27102m); tw=0.109 (2.77103m) To simplify calculation you may assume Ai=Ao (thin-wall approximation) (a) (10pts) Sketch and completely label the process, including inlet and outlet streams. State all assumptions and include given information. (b) (10pts) Determine temperature for physical properties and calculate Re. (c) (13pts) Choose the appropriate correlation, determine hi, and calculate the overall heat transfer coefficient (U) Identify the most important resistance term. (d) (12pts) Use the overall heat transfer design equation with the proper correction factor (F) to determine the required heat transfer area (A). 1) Sketch and Label the physical problem. 2) List ALL the Given information. 3) Clearly state your Assumptions 4) Indicate Figures, Tables, and correlations used to solve problems. 5) Show all work, including UNITS. *NOTE: In using Appendix use closest temperature. No need to interpolate. *