fluid_mechanics

Problems 457
120 m of 0.30-m-diameter
cast-iron pipe
F I G U R E P8.91
T
Diffuser
1 m
20 m
the flowrate passing between the tanks? Assume the friction factor
to be equal to 0.02 and minor losses to be negligible.
† 8.96 Gasoline is unloaded from the tanker truck shown in
Fig. P8.96 through a 4-in.-diameter rough-surfaced hose. This is a
“gravity dump” with no pump to enhance the flowrate. It is claimed
that the 8800-gallon capacity truck can be unloaded in 28 minutes.
Do you agree with this claim? Support your answer with appropriate
calculations.
*8.92 In some locations with very “hard” water, a scale can build
up on the walls of pipes to such an extent that not only does the
roughness increases with time, but the diameter significantly decreases
with time. Consider a case for which the roughness and diameter
vary as e 0.02 0.01t mm, D 50 (1 0.02t) mm,
where t is in years. Plot the flowrate as a function of time for t 0
to t 10 years if the pressure drop per 12 m of horizontal pipe remains
constant at ¢p 1.3 kPa.
8.93 Water flows from the nozzle attached to the spray tank shown
in Fig. P8.93. Determine the flowrate if the loss coefficient for the
nozzle (based on upstream conditions) is 0.75 and the friction factor
for the rough hose is 0.11.
Nozzle diameter
= 7.5 mm
F I G U R E P8.96
Midstate Gasoline
8.97 The pump shown in Fig. P8.97 delivers a head of 250 ft to
the water. Determine the power that the pump adds to the water.
The difference in elevation of the two ponds is 200 ft.
K Lexit
= 1.0
p = 150 kPa
Pump
0.80 m
40°
D = 15 mm
= 1.9 m
K Lvalve
= 5.0
K Lent
= 0.8
K Lelbow
= 1.5
Pipe length = 500 ft
Pipe diameter = 0.75 ft
Pipe roughness = 0
F I G U R E P8.93
8.94 When the pump shown in Fig. P8.94 adds 0.2 horsepower to
the flowing water, the pressures indicated by the two gages are
equal. Determine the flowrate.
Length of pipe between gages 60 ft
Pipe diameter 0.1 ft
Pipe friction factor 0.03
Filter loss coefficient 12
Filter
Pump
F I G U R E P8.97
8.98 Water flows through two sections of the vertical pipe shown
in Fig. P8.98. The bellows connection cannot support any force in
the vertical direction. The 0.4-ft-diameter pipe weighs 0.2 lbft, and
the friction factor is assumed to be 0.02. At what velocity will the
force, F, required to hold the pipe be zero?
Free jet
F
F I G U R E P8.94
8.95 Water is pumped between two large open tanks as shown in
Fig. P8.95. If the pump adds 50 kW of power to the fluid, what is
f = 0.020
Pipe weighs
0.20 lb/ft
D = 0.40 ft
Bellows
Water
Pump
Diameter
D m = 0.5 m
V
F I G U R E P8.98
Pipe length = 600 m
F I G U R E P8.95
8.99 Water is circulated from a large tank, through a filter, and back
to the tank as shown in Fig. P8.99. The power added to the water by
the pump is 200 ft # lbs. Determine the flowrate through the filter.