Look at figure below and use. Water (50°F) flows at 250 gpm through the pipe system at the bottom of this page. All piping is four inch (4") diameter cast iron. The distance between points A and B along the open flow path is 500 ft. Calculate the total head loss between points Aand B. Assume A and Bare at the same elevation. Use the following minor loss coefficients for the fittings:
Fitting Minor Loss Coefficient
Open Valve 0.20
90° Smooth Bend 0.35 (r/d = 1)
0.19 (r/d = 2)
0.16 (r/d = 4)
0.21 (r/d = 6)
0.28 (r/d = 8)
0.30 (r/d = 10)
Tee? 0.6 (Straight-through flow)
1.8 (Side-Outlet Flow)
90° Elbow 0.30
A town is installing a new 10" main to carry drinking water. The only section remaining to be installed is a segment through the middle of town. However, the excavators discover an archaeological site. The town decides to split the main into two sections, each looping around the site and reconnecting at the other end. The mayor decrees that "the velocity in each branch around the site shall be equal". The town lays 800 feet of 6" pipe to the north of the site and connects to the 10" main leading away from town. However, the town then finds out there is no more 6" pipe. Anywhere. The only pipe available is 8" pipe. The contractor, noting that "shall" is a legally binding term when a contract is signed, must lay the proper amount of 8" pipe such that the velocity in the two branches is the same. Determine: a) the length of 8" pipe required, b) if instead, 800 feet of 8" pipe is laid parallel to the 6" pipe, the minor loss coefficient, K, for a valve that must be placed in the 8" line to exactly cause the velocities in the two pipes to balance. Assume for purposes of solving this problem that turbulent flow exists and the resistance coefficients, f, for the 6" pipe and 8' pipe are 0.023 and 0.019, respectively.