fluid_mechanics

Problems 459
Elevation = 20 m
D = 0.08 m
= 200 m
f = 0.020
Elevation = 60 m
F I G U R E P8.112
D = 0.10 m
= 200 m
f = 0.015
D = 0.08 m
= 400 m
f = 0.020
Elevation = 0
8.113 (See Fluids in the News article titled “Deepwater pipeline,”
Section 8.5.2.) Five oil fields, each producing an output of Q barrels
per day, are connected to the 28-in.-diameter “main line pipe”
(A– B–C) by 16-in.-diameter “lateral pipes” as shown in Fig.
P8.113. The friction factor is the same for each of the pipes and
elevation effects are negligible. (a) For section A– B determine the
ratio of the pressure drop per mile in the main line pipe to that in
the lateral pipes. (b) Repeat the calculations for section B–C.
Q Lateral Q
Q
A B C
Main line Q
Q
F I G U R E P8.113
†8.114 As shown in Fig. P8.114, cold water (T 50 F) flows
from the water meter to either the shower or the hot water heater.
In the hot water heater it is heated to a temperature of 150 F. Thus,
with equal amounts of hot and cold water, the shower is at a comfortable
100 F. However, when the dishwasher is turned on, the
shower water becomes too cold. Indicate how you would predict
this new shower temperature (assume the shower faucet is not adjusted).
State any assumptions needed in your analysis.
8.116 A 2-in.-diameter orifice plate is inserted in a 3-in.-diameter
pipe. If the water flowrate through the pipe is 0.90 cfs, determine
the pressure difference indicated by a manometer attached to the
flow meter.
8.117 Air to ventilate an underground mine flows through a large
2-m-diameter pipe. A crude flowrate meter is constructed by placing
a sheet metal “washer” between two sections of the pipe. Estimate
the flowrate if the hole in the sheet metal has a diameter of 1.6 m and
the pressure difference across the sheet metal is 8.0 mm of water.
8.118 Water flows through a 40-mm-diameter nozzle meter in a
75-mm-diameter pipe at a rate of 0.015 m 3 s. Determine the pressure
difference across the nozzle if the temperature is (a) 10 °C,
or (b) 80 °C.
8.119 Air at 200 °F and 60 psia flows in a 4-in.-diameter pipe at
a rate of 0.52 lbs. Determine the pressure at the 2-in.-diameter
throat of a Venturi meter placed in the pipe.
8.120 A 2.5-in.-diameter flow nozzle is installed in a 3.8-in.-
diameter pipe that carries water at 160 °F. If the air–water
manometer used to measure the pressure difference across the meter
indicates a reading of 3.1 ft, determine the flowrate.
8.121 A 0.064-m-diameter nozzle meter is installed in a 0.097 m-
diameter pipe that carries water at 60 °C. If the inverted air–water
U-tube manometer used to measure the pressure difference across
the meter indicates a reading of 1 m, determine the flowrate.
8.122 Water flows through the Venturi meter shown in
Fig. P8.122. The specific gravity of the manometer fluid is 1.52.
Determine the flowrate.
6 in.
2 in.
3 in.
SG = 1.52
F I G U R E P8.122
8.123 Water flows through the orifice meter shown in Fig. P8.123
at a rate of 0.10 cfs. If d 0.1 ft, determine the value of h.
Q
Shower
Hot
Dishwasher
h
Cold
Water meter
Hot water heater
Q
2 in.
d
F I G U R E P8.123
F I G U R E P8.114
Section 8.6 Pipe Flowrate Measurement (Also see Lab
Problem 8.127.)
8.115 Obtain a photograph/image of a flowrate measurement device.
Print this photo and write a brief paragraph that describes the
measurement range of the device.
8.124 Water flows through the orifice meter shown in Fig. P8.123
such that h 1.6 ft with d 1.5 in. Determine the flowrate.
8.125 The scale reading on the rotameter shown in Fig. P8.125
and Video V8.14 (also see Fig. 8.46) is directly proportional to the
volumetric flowrate. With a scale reading of 2.6 the water bubbles
up approximately 3 in. How far will it bubble up if the scale reading
is 5.0?