CE 230-Engineering Fluid Mechanics Lecture # 31-32 Minor losses Characteristic curve of a pump Parallel pipes

Components of head loss Losses due to friction along the length of the pipe call MAJOR LOSS Losses at localized regions like inlets, outlets, bends.. CALL MINOR LOSS

Example 10.9 Find the elevation of the left reservoir given: D=15 cm Q= 0.028 m3/s ν = 4x10-5 m2/s S=0.9

Characteristic curve of a pump The head produced by a pump will depend on the discharge rate varying from maximum value when there is no flow and decreasing as Q increases. The nature of this variation is unique for every pump and is usually supplied by the manufacturer as a curve called the characteristic curve of the pump.

Characteristic curve of a pump If we place a pump of known c.c. in a pipe line and want to determine the head required from the pump apply the energy equation we could get an equation for hp hp will be a function of Q (system curve)

Example 10.11 Find the flow rate of water. The pump has the shown c.c. f=0.015 hp=30+127Q2

Flow in parallel pipes How much will flow in pipe 1 and 2? Key concept is the head difference between ant two junctions in the same regardless of the path.

Pipe networks Water distribution system Hardy cross method Iterative procedure CE delta hL=0