Double-pipe heat exchanger. This type of heat exchanger is composed of concentric pipes, with hot water flowing in the inner pipe while cold water flows in the annulus between the inner pipe wall and outer pipe wall. Hot water enters the inner pipe with a volumetric flow rate of 8 L/min, while cold water enters the annular space with a volumetric flow rate of 6 L/min. The inner pipe has an outer pipe diameter of 0.0127 m and wall thickness of 0.00076 m. The outer pipe has an outer pipe diameter of 0.0190 m and wall thickness of 0.00124 m.
1) What is the average velocity of the hot water stream?
2) What is the average velocity of the cold water stream?