For the pump and piping system of Prob. 14–39E, plot the required pump head H_required (ft of water column) as a function of volume flow rate V̇(gpm). On the same plot, compare the available pump head H_available versus V̇, and mark the operating point. Discuss.

Data from Problem 14–39E

A water pump is used to pump water from one large reservoir to another large reservoir that is at a higher elevation. The free surfaces of both reservoirs are exposed to atmospheric pressure, as sketched in Fig. P14–39E. The dimensions and minor loss coefficients are provided in the figure. The pump’s performance is approximated by the expression H_available = H₀ – aV̇², where the shutoff head H₀ = 125 ft of water column, coefficient a = 2.50 ft/gpm², available pump head H_available is in units of feet of water column, and capacity V̇ is in units of gallons per minute (gpm). Estimate the capacity delivered by the pump.

FIGURE P14–39E

Transcribed Image Text:

22-21 = 22.0 ft (elevation difference) D 1.20 in (pipe diameter) KL, entrance = 0.50 (pipe entrance) = 2.0 (valve 1) = 6.8 (valve 2) KL, valve 1 KL, valve 2 KL. elbow = 0.34 (each elbow-there are 3) KL, exit = 1.05 (pipe exit) L=124 ft (total pipe length) 8 = 0.0011 in (pipe roughness) V₁=0 Reservoir 22- 22-21 Valve 1 Z1 <-D Pump Reservoir V/₂=0 Valve 2