Water stream (density 994 kg/m3) is fed to the shell side of a shell and tube heat exchanger in a mass flow rate of 655.6 t/h. The inner diameter of the shell is 45 cm, it contains 77 tubes of diameter 25/30 mm. Give the linear velocity at the shell side in m/s.

Also 1- Explain for me how you find the Diameter of the tube side

2- What it means diameter 25/30 mm