Design a heat exchanger to pasteurize milk by steam in a dairy plant. Milk is to flow through a bank of $1\mathrm{.}2-$cm$-$ internal$-$diameter tubes while steam condenses outside the tubes at $1$ atm. Milk is to enter the tubes at $4$ degree C$,$ and it is to be heated to $72$ degree C at a rate of $15$ L$/$s$.$ Making reasonable assumptions, you are to specify the tube length and the number of tubes, and the pump for the heat exchanger.