A shell-and-tube heat exchanger is made of two standard steel tubes, as shown in Fig. 9.13. The outer tube has an OD of 718 in and the OD for the inner tube is 1/2 in. Each tube has a wall thickness of 0.049 in. Calculate the required ratio of the volume flow rate in the shell to that in the tube if the average velocity of flow is to be the same in each.
