The wind tunnel in the Mississippi State University Thermal and Fluid Dynamics Laboratory has a cooling water loop which is used to control the tunnel operating temperature. The loop is shown in Fig. P4-13. The water temperature is controlled by continuously dumping hot water and mixing in cool water from the plant water system.
The heat exchanger is composed of 22 copper tubes, each of which is! in. in diameter by 20 ft long and contains two close-pattern return bends. The inlet and exit frontal areas are both 72 square inches. The expansion and contraction loss coefficients for inlet and outlet headers should be based on sudden expansion/contraction and hydraulic diameters. The headers are 2 in. by 36 in. and are fed by 2-in. pipes. All pipes and fittings are copper BWG 14. The water temperature is typically 80°F.
Ignoring the dump and dump system, select a pump for this system which will deliver 25 gpm.