For numbers 19 to 21: A liquid having a density of 801 kg/m3 and a viscosity 1.49x10-3 Pa- s is flowing through a horizontal straight pipe of a velocity of 4.57 m/s. The commercial steel pipe is 1 ½ in nominal pipe size, schedule 40. For a length of a pipe of 61 m, do as follows: 19. Calculate the friction loss. a. 491 J/kg b. 350 J/kg c. 126 J/kg d. 278 J/kg 20. For smooth tube of the same inside diameter, calculate the friction loss. a. 410 J/kg b. 350 J/kg c. 100 J/kg d. 280 J/kg 21. What is the percent reduction of the F for the smooth tube? a. 21% b. 13% c. 42% d. 34%

19. b. 350 J/kg 20. d. 280 J/kg 21. a. 21%

MOMENTUM TRANSFER Flashcards by John Clavines Edradan

Convert 15.14 poises to kinematic viscosity in square feet per second
if the liquid has a specific gravity of 0.964.

a. 0.0169 ft2
/s
b. 0.0258 ft2
/s
c. 0.0333 ft2
/s
d. 0.0421 ft2
/s

a. 0.0169 ft2
/s

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The viscosity of a gas

a. decreases with increase in temperature
b. increases with increase in temperature
c. is independent of temperature
d. is independent of pressure for very high pressure intensities

b. increases with increase in temperature

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A piston of diameter 70.00 mm moves inside a cylinder of diameter
70.10 mm. Determine the percent decrease in force necessary to
move the piston when the lubricant warms from 0 to 1200C. Values
of μ for the lubricant are 0.01820 Pa-s at 00C and 0.00206 Pa-s at
1200C.

a. 72%
b. 89%
c. 63%
d. 55%

b. 89%

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The dimensionless number that characterizes the flows of fluid in a
conduit.

a. Nusselt number
b. Peclet number
c. Grashof number
d. Reynolds number

d. Reynolds number

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Turbulent flow generally occurs for cases involving

a. viscous fluid
b. very narrow passages for capillary tube
c. very slow motions
d. none of these

d. none of these

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Water at 800F at 10 ft/s through a 6 inches sch 40 steel pipe with
length of 1000 ft. The Reynolds number is

a. 330 000
b. 260 000
c. 550 000
d. 830 000

c. 550 000

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For numbers 7 to 8:
In an air pipeline, the flow has the following conditions at section 1:
250C, 1.8 bar, 15 m/s velocity, and 50 mm inside diameter of pipe.
At section 2 the conditions are: 250C, 1.3 bar, and 75 mm inside
diameter of pipe.

Calculate the mass flow rate of air.

a. 0.062 kg/s
b. 0.034 kg/s
c. 0.051 kg/s
d. 0.075 kg/s

Determine the velocity at the section 2.

a. 6.4 m/s
b. 7.5 m/s
c. 9.2 m/s
d. 3.3 m/s

a. 0.062 kg/s
c. 9.2 m/s

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Water flows through an 8 in (ID=7.981 in) steel pipe at an average
velocity of 6 ft/s. Downstream the pipe splits into an 8-in main and a
2 in (ID=2.067 in) bypass pipes. If the velocity in the bypass is twice
the velocity of the main pipe, calculate the volumetric flowrate in the
main pipe in ft3
/s.

a. 1.84
b. 2.31
c. 3.05
d. 4.69

a. 1.84

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Water at 200C enters an inclined 1-inch ID where the upstream point
is at 10 psig. The downstream point is ½ inch ID and 40 ft below the
upstream point where the water discharges at 30 gpm to the
atmosphere. What is the friction in ft of water?

a. 10.2
b. 8.6
c. 28.1
d. 45.2

c. 28.1

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Water at 200C is pumped at a constant rate of 9 m3
/h from a large
reservoir resting on the floor to the open top of an experimental
absorption tower. The point of discharges is 5 m above the floor, and
the frictional losses in the 50 mm pipe from the reservoir to the tower
amount to 2.5 J/kg. At what height in the reservoir must the water
level be kept if the pump can develop only 0.1 kW?

a. 2.50 m
b. 1.26 m
c. 3.84 m
d. 0.77 m

b. 1.26 m

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For numbers 12 to 13:
A pump draws 69.1 gal/min of a liquid solution having a density of
114.8 lb/ft3
from an open storage feed tank of large cross sectional
area through a 3-inch sch40 suction line. The pump discharges its
flow through a 2-inch sch40 line to an open overhead tank. The end
of the discharge line is 50 ft above the level of the liquid in the feed
tank. The friction losses in the piping system are 10 ft-lbf/lb.

What pressure must the pump develop?

a. 35 psi
b. 29 psi
c. 48 psi
d. 10 psi

What is the horsepower of the pump if the efficiency is 65%? The
flow is turbulent.

a. 3 hp
b. 7 hp
c. 5 hp
d. 2 hp

c. 48 psi
a. 3 hp

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For an ideal fluid flow, the Reynolds number is

a. 2100
b. 100
c. zero
d. infinity

d. infinity

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In a nozzle flow, the inlet conditions are P1=365 kPa gage and
D1=100 mm and the outlet conditions are P2=0 kPa gage and D2=50
mm. Find the flow rate and neglect viscous effects. The fluid is water.

a. 0.032 m3
/s
b. 0.055 m3
/s
c. 0.019 m3
/s
d. 0.028 m3
/s

b. 0.055 m3
/s

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In a certain chemical plant, the carbonate solution used in the
absorption tower is pumped continuously from the bottom of the lye
storage tank through a standard 4 in. pipe and then through sprays
head at the top of the scrubber. The depth of solution in the storage
tank is 10 ft and the vertical distance from the spray head to the
bottom of the tank is 110 ft.
In a test on this equipment the following data were obtained:
Rate of flow 200 gpm
Density 68.9 lb/ft3
Friction drop from tank to spray head 15 ft-lbf/lb
Gage pressure on spray head 5 psi
Power input to pump 14 hp
Calculate the efficiency of the pump.

a. 60%
b. 75%
c. 50%
d. 65%

c. 50%

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A water storage tank supplies water into a factory. Water is supplied
to the tank through a booster pump installed in the water line. The
theoretical pump horsepower required is 3.25 hp. What is the
monthly operating cost of the pump, if electrical power cost on the
average is P 3.73/kWh? The pump is 65% efficient and operates for
12 hours a day.

a. P 3300
b. P 7000
c. P 5000
d. P 9000

c. P 5000

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Water is stored in an elevated reservoir. To generate power, water
flows from this reservoir down through a large conduit to a turbine
and then through a similar-sized conduit. At a point in the conduit
89.5 m above the turbine, the pressure is 172.4 kPa, and a level 5 m
below the turbine, the pressure is 89.6 kPa. The water flow rate is
0.800 m3
/s. The output of the shaft of the turbine is 658 kW. The
water density is 1000 kg/m3
. If the efficiency of the turbine in
converting the mechanical energy given up by the fluid to the turbine
shaft is 89 %, calculate the friction loss in the turbine in J/g.

a. 97 J/kg
b. 85 J/kg
c. 81 J/kg
d. 76 J/kg

b. 85 J/kg

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For numbers 19 to 21:
A liquid having a density of 801 kg/m3 and a viscosity 1.49x10-3 Pa-
s is flowing through a horizontal straight pipe of a velocity of 4.57
m/s. The commercial steel pipe is 1 ½ in nominal pipe size, schedule 40. For a length of a pipe of 61 m, do as follows:

Calculate the friction loss.

a. 491 J/kg
b. 350 J/kg
c. 126 J/kg
d. 278 J/kg

For smooth tube of the same inside diameter, calculate the friction
loss.

a. 410 J/kg
b. 350 J/kg
c. 100 J/kg
d. 280 J/kg

What is the percent reduction of the F for the smooth tube?

a. 21%
b. 13%
c. 42%
d. 34%

b. 350 J/kg
d. 280 J/kg
a. 21%

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For numbers 22 to 23:
A steel pipe having an inside diameter of 13.25 inches is to be
designed to carry 48 000 bbl of oil per 24 hour day from a mid-
continent field to a refinery 580 miles from the source. The difference
in elevation of the two ends of the line is negligible. At an average
temperature involved, the oil has an absolute viscosity of 50
centipoises and a specific gravity of 0.87.

Calculate the horsepower required to overcome friction in the pipe
line.

a. 5100 hp
b. 1600 hp
c. 3800 hp
d. 4200 hp

Since the maximum allowable pressure in any section of the line is
650 psi, it will be necessary to insert additional pumping stations at
suitable intervals along the pipe line. What is the smallest number of
pumping stations required?

a. 15
b. 10
c. 7
d. 5

a. 5100 hp
b. 10

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What is the hydraulic diameter of a rectangular duct with dimensions
6 inches by 12 inches?

a. 8 inches
b. 10 inches
c. 10.63 inches
d. 11.86 inches

a. 8 inches

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The hydraulic diameter of concentric annular space where 1-in OD
pipe is located inside a 2-in ID pipe is

a. 1 in
b. 1.5 in
c. pi/4 in
d. 2 in

a. 1 in

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Water is flowing at a rate of 80 gpm through 50 ft of an annular
conduit made of ½ in and 1 ¼ in schedule 40 steel pipe. What is the
pressure drop in the 50 ft? Assume as average properties, a density
of 62.3 lb/ft3 and a viscosity of 0.88 centipoise.

a. 110 psia
b. 125 psia
c. 115 psia
d. 150 psia

d. 150 psia

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The pressure after the pump in a 6-inch inside diameter smooth pipe
conducting water is 20 psia. The water is discharged at an open tank
100 ft from the pump. Calculate the rate of discharge of water in ft3
/s.

a. 2.5
b. 5.8
c. 1.6
d. 3.6

d. 3.6

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A pump discharges ethanol at 380C into a smooth tube of 50 mm ID
at a gage pressure of 280 kPa. This pipe is 40 m long (total
equivalent length) and supplies ethanol at a gage pressure of 140
kPa to a reactor. What is the volumetric flow rate of ethanol to the
reactor? There is negligible change in elevation between the pump
and reactor. ρ = 820 kg/m3 and μ = 0.9 cP.

a. 0.01 m3
/s

b. 0.03 m3
/s
c. 0.02 m3
/s
d. 0.04 m3
/s

a. 0.01 m3
/s

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Water flowing at 2.27 m3
/hr at 320 K is pumped through a 40 mm ID
pipe, through a length of 150 m in a horizontal direction, and up
through a vertical height of 10 m. In the pipe there is a control valve,
equivalent to 200 pipe diameters, and other pipe fittings equivalent
to 60 pipe diameters. Also in the line is a heat exchanger across
which the head lost is 1.5 m water. Assume that the main pipe has a
roughness of 0.2 mm What power must be supplied to the pump if it
is 60 percent efficient?

a. 97 W
b. 188 W
c. 136 W
d. 205 W

c. 136 W

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For numbers 30 to 31: A cooling water pump is operating at a speed of 2800 rpm. Its flow rate is 1000 gal/min at a head of 160 ft. 30. What is the power requirement of the pump? a. 10 kW b. 30 kW c. 20 kW d. 40 kW 31. If the pump speed is increased to 5000 rpm, determine the new power requirement. a. 47 kW b. 133 kW c. 80 kW d. 170 kW

30. b. 30 kW 31. d. 170 kW

32. When a fluid flows through a reducer in a piping system, the velocity at the outlet end is _ the velocity at the inlet. a. less than b. more than c. the same as d. one-half

b. more than

33. For pipes that must be broken at intervals for maintenance, the connector used should be a/an a. union b. reducer c. tee d. elbow

a. union

34. Which valve is used accurately to regulate the flow of liquids and gases at low flow rates? a. needle valve b. check valve c. ball valve d. globe valve

a. needle valve

35. Calculate the radius of capillary tube in mm, such that it is a flow of a viscous fluid . Kinematic viscosity 0.000043 m2 /s Length of tube 50.2 cm Mass flow rate 0.003 kg/s Density of fluid 955 kg/m3 Pressure drop 4.77 atm a. 0.32 b. 0.18 c. 0.75 d. 0.45

c. 0.75

36. Methane at 60 0F is flowing at a steady mass rate through a steel main having an inside diameter of 12 inches. The absolute pressure drops from 40 atm to 20 atm, in a length of 500 miles substantially horizontal pipe. Calculate the hourly rate of flow expressed as ft3 measured at 600F and normal barometric pressure. a. 650000 cfh b. 380000 cfh c. 520000 cfh d. 440000 cfh

a. 650000 cfh

37. Nitrogen gas is flowing through a 4” sch40 steel pipe at 25 0C. The flow rate is 7.4 x10-2 kg/s and the flow is assumed isothermal. The pipe is 3000 m long and the inlet pressure is 200 kPa abs. What is the outlet pressure? a. 189 kPa b. 155 kPa c. 170 kPa d. 146 kPa

a. 189 kPa

For numbers 38 to 39: Calculate the theoretical adiabatic horsepower to compress 1000 cfm of helium from standard atmospheric pressure and 800F to 200 psig, 38. In a single stage. a. 308 hp b. 228 hp c. 210 hp d. 546 hp 39. In 2 stages. a. 308 hp b. 228 hp c. 210 hp d. 546 hp

38. a. 308 hp 39. b. 228 hp

Nitrogen is to be compressed in four stages from 14.7 psia to 3500 psig. What would be the pressure in the third stage? a. 894 psia b. 227 psia c. 753 psia d. 561 psia

a. 894 psia

41. A pitot tube with U-tube water manometer is attached to a horizontal pipe of 4 in inside diameter. If the manometer reading is 15 in, determine the volumetric flowrate, in gpm, of oil in the pipe. The pitot opening is placed at the center of the pipe. The oil has a specific gravity of 0.84 and a viscosity of 0.0336 lb/ft-s. a. 77 b. 55 c. 32 d. 94

a. 77

42. Which of the following is not true? a. A pump will operate safely if its NPSH is greater than zero. b. Fans and blowers are used to transport gases. c. Pumps and blowers increase the mechanical energy of the fluid. d. The power loss due to friction in a venturi meter is greater than in an orifice meter.

d. The power loss due to friction in a venturi meter is greater than in an orifice meter.

43. Which statement is not true? a. Potential flow is a flow of compressible fluids with no shear. b. Rotameters are variable-head meters. c. There are 8 schedule numbers in used for standard pipes. d. Roughness has no appreciable effect on the friction factor when flow is laminar.

c. There are 8 schedule numbers in used for standard pipes.

44. A sharp-edged circular orifice is to be used to measure the flowrate of water at 200C (ρ = 1000 kg/m3 , μ = 1 mPa-s) in a pipeline with an internal diameter of 250 mm. The orifice diameter is 50 mm. The reading of a mercury manometer at the throat tap position is 242 mm. Calculate the flowrate in L/s. a. 5.85 L/s b. 6.64 L/s c. 7.11 L/s d. 9.27 L/s

d. 9.27 L/s

45. A sharp edged orifice meter is to be fabricated to measure water flowing at a rate not exceed 1200 cfh, with a differential head of 30 inHg. What orifice diameter in inches is required if D2/D1=1/5? a. 1.5 b. 1.0 c. 2.0 d. 2.5

a. 1.5

ADDITIONAL PROBLEM 1. The water output of a purification plant is measured by the use of a standard Venturi meter with a throat 12 in in diameter. The differential head from the upstream section to the throat, measured on a vertical U-tube manometer containing mercury was found to be 3 in. Calculate the rate of water flow expressed as gal/day. Assume β = 0.5. a. 7.4x106 b. 5.6x106 c. 4.3x106 d. 1.9x106

a. 7.4x106

ADDITIONAL PROBLEM 2. A Venturi meter is to be installed in a 100 mm line to measure flow of water at 15˚C. The minimum flowrate is 75 m3 /hr. The manometer reading is 1.25 m Hg. What is the throat diameter? a. 4 mm b. 19 mm c. 28 mm d. 39 mm

d. 39 mm

ADDITIONAL PROBLEM 3. Water at 60˚F flows through a 3 in Sch40 pipe. A pitot tube in the pipe shows a 3 inHg differential. If the pitot tube is located at the center of the pipe, what is the mass flowrate of water? a. 39 lb/s b. 50 lb/s c. 31 lb/s d. 67 lb/s

a. 39 lb/s

ADDITIONAL PROBLEM 4. A pitot tube is used to measure the flowrate of water at 20˚C in the center of a pipe having an inside diameter of 102.3 mm. The manometer reading is 78 mm CCl4 at 20˚C. The pitot tube coefficient is 0.98. Calculate the volumetric flowrate of water in m3 /s. a. 6.31x10-3 b. 8.09x10-3 c. 4.27x10-3 d. 1.82x10-3

a. 6.31x10-3

ADDITIONAL PROBLEM 5. What is the differential reading in a pitot tube inserted in an 8 in nominal pipe carrying 1600 gpm of water? Assume mercury in the pitot tube. a. 3.9 inHg b. 2.1 inHg c. 5 inHg d. 12 inHg

b. 2.1 inHg

ADDITIONAL PROBLEM 6. Natural gas, which is essentially methane, is being pumped through a 1.016 m diameter pipeline for a distance of 160900 m at a rate of 2.077 kmol/s. It can be assumed that the line is isothermal at 288.8 K. The pressure at the discharge end of the line is 170300 Pa. Calculate the pressure at the inlet of the pipe. The viscosity of methane can be taken as 0.0000104 Pa-s. a. 200 kPa b. 360 kPa c. 520 kPa d. 660 kPa

d. 660 kPa

ADDITIONAL PROBLEM 7. A town delivers its water supply from a lake nearby. The inlet to the pump is 15 ft above the lake surface, and the water level in the tank is kept constant at 310 ft above the pump discharge. The friction loss is 140 ft-lbf/lbm of water through 6000 ft of 4 in pipeline which includes the total equivalent length of all piping from the lake to the water tower. The pump capacity is 6000 gph and the water pump set is 85% efficient. What would be the hourly pumping cost if electric power is 7.5/kW-hr? a. 77.4 b. 189.5 c. 139.3 d. 203.6

a. 77.4

ADDITIONAL PROBLEM 8. Hot water in an open storage tank at 82.2˚C is being pumped at a rate of 0.379 m3 /min from the storage tank. The line from the storage tank to the pump suction is 6.1 m of 2 in Sch40 steel pipe and it contains 3 elbows. The discharge line after the pump is 61 m of 2 in Sch40 steel pipe and contains 2 elbows. The water discharges to the atmosphere at a height of 6.1 m above the water level in the storage tank. What is the power requirement of the pump if its efficiency is 75%? a. 1.5 kW b. 2.3 kW c. 3.2 kW d. 5.1 kW

a. 1.5 kW

ADDITIONAL PROBLEM 9. How many gallons of water at 68˚F can be delivered through a 1320 ft length of smooth 6 in ID pipe under a pressure difference of 0.25 psi? a. 5210 gal/hr b. 1235 gal/hr c. 4100 gal/hr d. 3245 gal/hr

c. 4100 gal/hr

ADDITIONAL PROBLEM 10. Unrefined oil whose density and viscosity are 920 kg/m3 and 0.0002 m2 /s, respectively, is pumped through a 75 m long 4 in ID pipe. The pump requires 3 kW power, and its efficiency is 70%. What is the average mass flowrate of oil through the pipe? a. 6 kg/s b. 10 kg/s c. 14 kg/s d. 18 kg/s

d. 18 kg/s

EXERCISES 1. A 280 km long pipe connects two pumping stations. If 0.56 m3/s are to be pumped through 0.62 m diameter line, the discharge station is 250 m lower in elevation than the upstream station and the discharge pressure is to be maintained at 300 kPa. Determine the power in kW required to pump the oil. For the oil, υ= 4.5 x10-6 m2/s and ρ= 810 kg/m3. The inlet pressure may be taken as atmospheric. a. 4500 b. 3500 c. 5600 d. 3500

a. 4500

EXERCISES 2. A town derives its water supply from lake nearby, pumping it up to a standpipe on the highest hill. The intake to the system is 10 ft below the lake surface, the inlet to the pump is 15 ft above lake surface, and the water level in the tower is kept constant at 310 ft above the pump discharge. The friction loss is 140 ft-lbf/lbm of water through the 6000 ft of 4 inch pipeline which includes the total equivalent length of all piping from the lake to the water tower. If the pump capacity is 6000 GPH and the water pump set is 85% efficient, what would be the hourly pumping cost is electric power is 7.50 per KW-hr? a. 77.40 b. 189.50 c. 139.30 d. 203.60

a. 77.40

EXERCISES For numbers 3 to 4: Cooling water at 220C flows through a 25 mm inside diameter smooth tube of length 10 m. If the pressure drop throughout the pipe is 20 kPa. 3. What is the velocity of water in the pipe? a. 2.24 m/s b. 3.11 m/s c. 3.41 m/s d. 4.68 m/s 4. What is the mass flow rate at the outlet of the pipe? a. 1.01 kg/s b. 1.11 kg/s c. 1.73 kg/s d. 2.14 kg/s

3. a. 2.24 m/s 4. b. 1.11 kg/s

EXERCISES For numbers 5 to 6: A pitot tube is used to measure the flow rate of water at 200C in the center of the pipe having an inside diameter of 102.3 mm. The manometer reading is 78 mm of carbon tetrachloride at 200C. The pitot tube coefficient is 0.98. 5. Calculate the average velocity of fluid inside the pipe. a. 0.44 m/s b. 0.55 m/s c. 0.11 m/s d. 0.77 m/s 6. Calculate the volumetric flow rate of water in m3/s? a. 6.37x10-3 b. 8.09x10-3 c. 4.27x10-3 d. 1.82x10-3

5. d. 0.77 m/s 6. a. 6.37x10-3

EXERCISES 7. A venturi meter is to be installed in a 100 mm line to measure flow of water at 15 0C. The minimum flow rate is 75 m3/hr. The manometer reading is 1.25 m of Hg. What is the throat diameter? a. 3.90 mm b. 18.5 mm c. 27.6 mm d. 39.2 mm

d. 39.2 mm

EXERCISES For numbers 8 to 10: Air at 288 K and 275 kPa absolute enters a pipe is flowing in isothermal compressible flow in a compressible flow in a commercial pipe having an ID of 0.080 m. The length of the pipe is 60 m. The mass velocity at the entrance to pipe is 165.5 kg/m2-s. Viscosity is 1.04 x10-5 kg/m-s. 8. Calculate the pressure at the exit. a. 2.1 x102kPa b. 3.0 x102kPa c. 2.6 x102kPa d. 3.3 x102kPa 9. Compute the maximum allowable velocity that can be attained. a. 380 m/s b. 150 m/s c. 110 m/s d. 290 m/s 10. Compute the actual velocity, v2. a. 16 m/s b. 21 m/s c. 28 m/s d. 64 m/s

8. a. 2.1 x102kPa 9. d. 290 m/s 10. d. 64 m/s

EXERCISES 11. Water at 60 0F flows through a 3“ sch40 pipe. A pitot tube in the pipe shows a 3” Hg differential. If the pitot tube is located at the center of the pipe, what is the mass flowrate of water? a. 37.1 lb/s b. 49.6 lb/s c. 40.5 lb/s d. 67.3 lb/s

a. 37.1 lb/s

EXERCISES 12. How many gallons of water at 68˚F can be delivered through a 1320 ft. length of smooth 6.00- in ID pipe under a pressure difference of 0.25 psi? a. 5210 gal/hr b. 1235 gal/hr c. 4060 gal/hr d. 3245 gal/hr

c. 4060 gal/hr

EXERCISES 13. Water flows in a 50 mm pipe, 100 m long, whose roughness ε is equal to 0.013 mm. If the pressure drop across this length of pipe is not to exceed 50 kN/m2, what is the maximum allowable water velocity? The density and viscosity of water may be taken as 1000 kg/m3 and 1.0 mN s/m2 respectively. a. 1.6 m/s b. 3.3 m/s c. 2.8 m/s d. 4.0 m/s

a. 1.6 m/s

EXERCISES 14. Specify the orifice diameter for measuring 100000 standard cu feet (at 600F and 1 atm) per hour of propane flowing through a pipe 12-in in diameter at a pressure of 10 psig and 800F. the reading across the orifice should not be more than 5 in of mercury. a. 1.26 in b. 3.85 in c. 2.67 in d. 4.09 in

b. 3.85 in

EXERCISES 15. Water at 600F flows from a lake through 500 ft of 4-in ID cast iron pipe at a water turbine 250 ft below the surface of the lake. After flowing through the turbine, the water is discharged into the atmosphere through a horizontal 50 ft section of the same pipe. The turbine power output is 10 hp when the water in the discharge pipe is flowing at 5 ft/s. What is the turbine efficiency? a. 86% b. 65% c. 77% d. 50%

a. 86%

EXERCISES 16. Calculate the theoretical horsepower required to compress 100 cfm of carbon dioxide at 60 0F and 1 atm to 10 atm in a single stage adiabatic compressor. Use Cp/Cv = 1.3 a. 12 b. 16 c. 20 d. 25

c. 20

EXERCISES For numbers 17-18. Nitrogen is to be fed through a 15 mm-id commercial steel pipe 11.5 m long to a synthetic ammonia plant. Calculate the downstream pressure in the line for a flow rate of 1.5 mol/s, an upstream pressure of 600 kPa, and a temperature of 27°C throughout. The average Fanning friction factor may be taken as 0.0066. 17. Calculate the downstream pressure a. 450 kPa b. 525 kPa c. 508 kPa d. 413 kPa 18. Determine the Mach number at the end of the pipe. a. 0.01 b. 0.35 c. 0.14 d. 0.26

17. c. 508 kPa 18. c. 0.14

EXERCISES 19. Heavy crude oil is to be pumped below the critical velocity through ten miles horizontal piping. Determine the percentage saving in horsepower by preheating the oil to 1400F before pumping at the same rate. Data: At 600F: Density = 59 lb/cu ft Viscosity = 3500 cP At 1400F: Density = 58 lb/cu ft Viscosity = 200 cP a. 88% b. 82% c. 94% d. 96%

c. 94%

20. You are in the field-piping area of a refinery, without a calculator or friction factor chart, doing an inspection with your manager. The flow through a pipe A is always fully turbulent. While you are watching the gauges of pipe A, which read pressure drop through the length of the pipe, the pressure increases by a factor of two. Your manager wants to know what is happening. You know that that the two valves are closed downstream, and the density and viscosity remain unchanged. In five seconds you figure out the flowrate increase, what do you tell to your manager? a. Tell your manager, "The flowrate increased by 20%." c. Tell your manager, "The flowrate increased by 80%." d. Tell your manager, "The flowrate increased by 100%.

b. Tell your manager, "The flowrate increased by 40%."

PBE What is the hydraulic diameter of a 200 mm by 300 mm rectangular duct which air flows? A. 0.29 m B. 0.24 m C. 0.12 m D. 0.06 m

PBE What is the hydraulic mean diameter of the annular space between 40 mm and a 50 mm tube? A. 30 mm B. 35 mm C. 10 mm D. 45 mm

PBE For the laminar flow of a fluid in a circular pipe of radius R, the Hagen-Poiseuille equation predict the volumetric flowrate to be proportional to A. R^0 B. R C. R^2 D. R^4

D. R^4

PBE Pipes having diameter 14 inches or more are designated by their A. inside diameter B. schedule number C. cross-sectional area D. outside diameter

D. outside diameter

PBE Water (density = 62.4 lb/ft3, viscosity = 1 cP) is pumped from a large reservoir on the floor at a rate of 80 gpm to the top of a smaller tower. The discharge point is 20 ft above the centerline of the pump. Frictional and other (contraction, expansion, etc.) losses in suction and discharge lines amount to 1.5 ft head of liquid. If the pump develops only 1/4 hp, the water height (ft) in the reservoir must be closest to A. 8.5 ft B. 6.3 ft C. 9.1 ft D. 7.2 ft

C. 9.1 ft

A 150 mm diameter pipe carries 81.3 L/s of water. The pipe branches into two pipes one is 50 mm in diameter and the other is 75 mm. What is the velocity in the 75 mm pipe if the velocity of the flow in the 50 mm pipe is 10 m/s? A. 12.75 m/s B. 15.75 m/s C. 13.96 m/s D. 19.43 m/s

C. 13.96 m/s

PBE When the flow is laminar A. the pressure drop is proportional to the first power of the velocity. B. the pressure drop is not affected by the velocity. C. the pressure drop is proportional to the square of the velocity. D. the pressure drop is inversely proportional to the velocity.

A. the pressure drop is proportional to the first power of the velocity.

PBE What is the theoretical minimum consumption of the free air to lift 100 gpm of water through a height of 50 ft (neglecting frictional losses) by means of an acid egg? Assume ΔP is 14.7 psia. A. 19.7 ft^3/min B. 44.9 ft^3/min C. 30.5 ft^3/min D. 26.5 ft^3/min

A. 19.7 ft^3/min

PBE Sulfuric acid is pumped at 3 kg/s through a 60 m length of smooth 25 mm pipe. Calculate the drop in pressure. Density of acid = 1840 kg/m3. Viscosity of acid = 25 mN-s/m2. Calculate the drop in pressure. A. 770 kPa B. 510 kPa C. 650 kPa D. 860 kPa If the pressure drop falls by one half, what will be the new flowrate? A. 3.3 kg/s B. 4.0 kg/s C. 2.8 kg/s D. 1.9 kg/s

D. 860 kPa D. 1.9 kg/s

PBE Unrefined oil whose density and kinematic viscosity are 920 kg/m3 and 0.0002 m2/s, respectively, is pumped through a 75-m long 4-in ID pipe. The pump requires 3 kW power and its efficiency is 70%. What is the Reynolds number? A. 3031 B. 1350 C. 1248 D. 3575

C. 1248

PBE A 6-in standard horizontal pipe delivers water at a velocity of 10 ft/s to a m3 pond from a river. The equivalent length of the pipe is 1000 ft. If the water temperature is 80degF, the flow is A. plug flow B. turbulent flow C. transition region D. laminar flow If the water temperature is 80degF, the theoretical horse power of the pump is A. 9 B. 12 C. 6 D. 18

B. turbulent flow B. 12

PBE The water output of a purification plant is measured by the use of a standard venturi meter having a throat 12-inches in diameter. The differential head from the upstream section to the throat, measured on a vertical U-tube manometer containing mercury was found to be 3 inches. Calculate the rate of water flow expressed as gal per 24 hour-day. Assume D2/D1 is 0.5. A. 7.3x10^6 B. 4.3x10^6 C. 5.6x10^6 D. 1.9x10^6

A. 7.3x10^6

PBE Petroleum oil is flowing isothermally through a horizontal pipe line having an actual inside diameter of 4.03 inches. A properly made pitot tube is inserted at the center line of the pipe. And its leads are filled with oil and attached to a vertical glass U-tube with oil and water. The difference in water levels is found to be 3 ft. Based on the data given below, calculate the rate of flow of oil expressed as cubic feet per minute. Data: Oil has a specific gravity of 0.9 and a viscosity scale, t of 200 Saybolt second A. 24.9 B. 10.4 C. 12.3 D. 20.5

C. 12.3

PBE Water flowing at 1.5 L/s in a 0.05 m diameter tube is metered by means of a simple orifice of diameter 0.025m. If coefficient of discharge is 0.62, what will be the reading on a mercury-under- water manometer connected to the meter? A. 92 mm B. 60 mm C. 77 mm D. 86 mm

A. 92 mm

PBE Natural gas which may be assumed to be methane is to be transferred through a 100-mile section of a 40 in ID pipeline at a rate of 150000000 cu. ft per 24 hr, measured at 60 0F and standard atmospheric pressure. The gas is delivered to the compressor at substantially atmospheric pressure and 60 0F and is to at 10 psig pressure at the discharge end of the line. Assume methane to be ideal gas. Calculate the pressure at the compressor exit. A. 92 psia B. 63 psia C. 80 psia D. 77 psia What power is required for pumping? A. 13 800 hp B. 15 300 hp C. 11 200 hp D. 12 500 hp

A. 92 psia B. 15 300 hp

PBE A pump that works at 5kW delivers brine with a density of 1150kg/m3 from the bottom a supply tank to the bottom of another tank at a velocity of 3.25m/s. The discharge in 1.10m above the supply and the line between the two open tanks in 45m. The line consists of elbows, tees and valves and you have calculated that the total form friction from these fittings and valves is 2.45 J/kg. you have also determined that the skin Darcy friction factor is 0.03. If the pump is 80% efficient and you assumed that flow is incompressible, what is the pipe internal diameter in cm. A. 12 cm B. 10 cm C. 16 cm D. 14 cm

D. 14 cm

PBE A solution of specific gravity of 1.25 is to be pumped at a rate of 50 gpm from an open storage tank to the top of an absorption tower. It discharges into the tower through openings equivalent in are to a standard one-inch pipe. The pressure in the tower is 10 psig. The point of discharge is 80 ft above the level of the solution in the storage tank. The pump intake is through a standard 2-inch pipe, 6 ft below the level of the solution in the tank. It discharges through a 2-inch standard line at substantially the same level. The friction head in the suction line is estimated to be 1.6 feet and in the discharge line is 9.6 feet of solution. If the pump efficiency is 70%. How much horsepower must be applied to the pump shaft? A. 5 hp B. 6 hp C. 4 hp D. 3 hp What pressure (psi) be indicated by gage at the inlet of the pump? A. 5.8 B. 4.6 C. 2.4 D. 3.9 What pressure (psi) would be indicated by gage at the pump’s exit? A. 62 B. 88 C. 70 D. 59

D. 3 hp C. 2.4 A. 62

PBE A horizontal tubular type of boiler uses crude oil consisting substantially of hydrocarbons. The oil is available at 700F and has a specific gravity of 0.90 and viscosity of 50 cP. In actual operation, water is fed to the boiler at a temperature 600F and vaporized to form steam at a gauge pressure of 100 psi and 98% quality of steam at a steam generation rate of 10 lb of steam per lb of oil fired. The average analysis of the flue gases is as follows: CO2 = 11%; CO = 0.5%; O2 = 6%; and N2 = 82.5%. At normal running rate the boiler generates 3450 lb of steam per hour. The boiler water is available from a well 30 ft below the feed line and the water line consists of 200 ft (total and equivalent) of 1-in standard steel pipe. The oil feed comes from a reservoir under a suitable head. The feed line consists of standard 3/4 in steel pipe. Calculate the Reynold number of the oil. A. 77 B. 53 C. 60 D. 84

B. 53

Most commonly used joint in the underground pipe lines is the A. sleevejoint B. expansion joint C. flange D. coupling

A. sleevejoint

PBE Schedule number of a pipe, which is a measure of its wall thickness, is given by A. 1000 P'/S B. 100 P'/S C. 1000 S/P' D. 10000 P'/S

A. 1000 P'/S

PBE Water hammer in a pipeline results from the A. None of these B. rapid pressure change due to a rapid change in the rate of flow. C. pressure increase due to closure of a valve resulting in decrease in rate of flow. D. bursting of pipelines due to closure by a valve.

B. rapid pressure change due to a rapid change in the rate of flow.

PBE Molten soap mass is transported by a _________ pump. A. reciprocating B. diaphragm C. centrifugal D. gear

C. centrifugal

PBE Nominal size of the discharge pipe of a pump is usually the nominal size of the inlet pipe. A. larger than B. same as C. twice D. smaller than

D. smaller than

PBE Location of vena-contracta in an orificemeter does not depend upon the A. pipe roughness. B. density, viscosity & compressibility of the fluid. C. ratio of pipe diameter to orifice diameter. D. type of orifice.

D. type of orifice.

PBE High specific speed of a pump implies that, it is a/an pump. A. centrifugal B. None of these C. mixed flow D. axial flow

D. axial flow