Fill in the blank. Show your work. a. 1000 J = Cal. b. ft-lbf = energy to lift a 10 N weight through an elevation difference of 125m. c. 12000 Btu = kWh. d. 32 ft-lbf/s = hp. e. [E] = [energy] = __
Read more- Physics / Engineering Fluid Mechanics 10 / Chapter 7 / Problem 7.37
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Textbook Solutions for Engineering Fluid Mechanics
Question
Firefighting equipment requires that the exit velocity of the firehose be 30m/sat an elevation of 45 m above the hydrant. The nozzle at the end of the hose has a contraction ratio of 4:1 (A,/Ahose = 1/4). The head loss in the hose is 8V2 /2g, where V is the velocity in the hose. What must the pressure be at the hydrant to meet this requirement? The pipe supplying the hydrant is much larger than the firehose.
Solution
The first step in solving 7 problem number 37 trying to solve the problem we have to refer to the textbook question: Firefighting equipment requires that the exit velocity of the firehose be 30m/sat an elevation of 45 m above the hydrant. The nozzle at the end of the hose has a contraction ratio of 4:1 (A,/Ahose = 1/4). The head loss in the hose is 8V2 /2g, where V is the velocity in the hose. What must the pressure be at the hydrant to meet this requirement? The pipe supplying the hydrant is much larger than the firehose.
From the textbook chapter THE ENERGY EQUATION you will find a few key concepts needed to solve this.
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Firefighting equipment requires that the exit velocity of the firehose be 30m/sat an
Chapter 7 textbook questions
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Chapter 7: Problem 7 Engineering Fluid Mechanics 10
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Chapter 7: Problem 7 Engineering Fluid Mechanics 10
From the list below, select one topic that is interesting to you. Then, use references such as the Internet to research your topic and prepare one page of documentation that you could use to present your topic to your peers. a. Explain how hydroelectric power is produced. b. Explain how a Kaplan turbine works, how a Francis turbine works, and the differences between these two types of turbines. c. Explain how a horizontal-axis wind turbine is used to produce electrical power. d. Explain how a steam turbine is used to produce electrical power.
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Chapter 7: Problem 7 Engineering Fluid Mechanics 10
Using Section 7.1 and other resources, answer the following questions. Strive for depth, clarity, and accuracy. Also, strive for effective use of sketches, words, and equations. a. What are the common forms of energy? Which of these forms are relevant to fluid mechanics? b. What is work? Describe three example of work that are relevant to fluid mechanics. c. What are the most common units of power? d. List three significant dilferences between power and energy.
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Chapter 7: Problem 7 Engineering Fluid Mechanics 10
Apply the grid method to each situation. a. Calculate the energy in joules used by a 1 hp pump that is operating for 6 hours. Also, calculate the cost of electricity for this time period. Assume that electricity costs $0.15 per kW-hr. b. A motor is being to used to turn the shaft of a centrifugal pump. Apply Eq. (7.3b) on p. 255 of 7.2 to calculate the power in watts corresponding to a torque of 100 lbf-in and a rotation speed of 850 rpm. c. A turbine produces a power of 7500 ft-lbf/s. Calculate the power in hp and in watts.
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Chapter 7: Problem 7 Engineering Fluid Mechanics 10
Energy (select all that are correct): a. has same units as work b. has same units as power c. has same units work/time d. can have units of Joule e. can have units of Watt f. can have units of ft-lbf g. can have units of calories
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Chapter 7: Problem 7 Engineering Fluid Mechanics 10
Power (select all that are correct) a. has same units as energy b. has same units as energy/time c. has same units as work/time d. can have units of Joule e. can have units of Watt f. can have units of horsepower g. can have units of ft-lbf
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Chapter 7: Problem 7 Engineering Fluid Mechanics 10
Estimate the power required to spray water out of the spray bottle that is pictured in Fig. 7.2a on p. 254 of 7.2. Hint: Make appropriate assumptions about the number of sprays per unit time and the force exerted by the finger.
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Chapter 7: Problem 7 Engineering Fluid Mechanics 10
The sketch shows a common consumer product called the Water Pik. This device uses a motor to drive a piston pump that produces a jet of water (d = I mm, T = 10C) with a speed of 27 m/s. Estimate the minimum electrical power in watts that is required by the device. Hints: (a) Assume that the power is used only to produce the kinetic energy of the water in the jet; and (b) in a time interval M, the amount of mass that flows out the nozzle is tom, and the corresponding amount of kinetic energy is (6-m V2 /2).
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Chapter 7: Problem 7 Engineering Fluid Mechanics 10
An engineer is considering the development of a small wind turbine (D = 1.25 m) for home applications. The design wind speed is IS mph at T = 10C and p = 0.9 bar. The efficiency of the turbine is 11 = 20%, meaning that 20% of the kinetic energy in the wind can be extracted. Estimate the power in watts that can be produced by the turbine. Hint: In a time interval6.t, the amount of mass that flows through the rotor is tom = mtot, and the corresponding amount of kinetic energy in this flow is (6.mV2 /2)
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Chapter 7: Problem 7 Engineering Fluid Mechanics 10
The application of Reynolds transport theorem to the first law of thermodynamics (select all that are correct) a. refers to the increase of energy stored in a closed system b. extends the applicability of the first law from a closed system to an open system (control volume) c. refers only to heat transfer, and not to work
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Chapter 7: Problem 7 Engineering Fluid Mechanics 10
Using Section 7.3 and other resources, answer the questions below. Strive for depth, clarity, and accuracy while also combining sketches, words, and equations in ways that enhance the effectiveness of your communication. a. What is the kinetic-energy correction factor? Why do engineers use this term? b. What is the meaning of each variable (a, A, V, V) that appears in Eq. (7.21) on p. 260 of 7.3? c. What values of a are commonly used?
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Chapter 7: Problem 7 Engineering Fluid Mechanics 10
For this hypothetical velocity distribution in a wide rectangular channel, evaluate the kinetic-energy correction factor a.
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Chapter 7: Problem 7 Engineering Fluid Mechanics 10
For these velocity distributions in a round pipe, indicate whether the kinetic-energy correction factor a is greater than, equal to, or less than unity.
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Chapter 7: Problem 7 Engineering Fluid Mechanics 10
An approximate equation for the velocity distribution in a pipe with turbulent flow is v (y)" Vmax = -;:;; where V mu is the centerline velocity, y is the distance from the wall of the pipe, r0 is the radius of the pipe, and 11 is an exponent that depends on the Reynolds number and varies between 1/6 and 1/8 for most applications. Derive a formula for a as a function of 11. What is a if 11 = 1/7?
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Chapter 7: Problem 7 Engineering Fluid Mechanics 10
An approximate equation for the velocity distribution in a rectangular channel with turbulent flow is where ll.uax is the velocity at the surface,y is the distance from the floor of the channel, dis the depth of flow, and n is an exponent that varies from about 1/6 to 1/8 depending on the Reynolds number. Derive a formula for a as a function of n. What is the value of a for n = 1/7?
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Chapter 7: Problem 7 Engineering Fluid Mechanics 10
The following data were taken for turbulent flow in a circular pipe with a radius of 3.5 em. Evaluate the kinetic energy correction factor. The velocity at the pipe wall is zero.
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Chapter 7: Problem 7 Engineering Fluid Mechanics 10
Using Section 7.3 and other resources, 3nswer the questions below. Strive for depth, clarity, and accuracy. Also, strive for effective use of sketches, words, and equations. a. What is head? How is head related to energy? To power? b. What is head of a turbine? c. How is head of a pump related to power? To energy? d. What is head loss?
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Chapter 7: Problem 7 Engineering Fluid Mechanics 10
Part (a) only Using Sections 7.3 and 7.7 and using other resources, answer the following questions. Strive for depth, clarity, and accuracy. Also, strive for effective use of sketches, words and equations. a. What are the five main terms in the energy equation (7.29) on p. 262 of 7.3? What does each term mean? b. How are terms in the energy equation related to energy? To power? c. What assumptions are required for using the energy equation (7.29) on p. 262 of 7.3?
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Chapter 7: Problem 7 Engineering Fluid Mechanics 10
Using the energy equation (7.29 on p. 262 of 7.3), prove that fluid in a pipe will flow from a location with high piezometric head to a location with low piezometric head. Assume there are no pumps or turbines and that the pipe has a constant diameter.
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Chapter 7: Problem 7 Engineering Fluid Mechanics 10
Water flows at a steady rate in this vertical pipe. The pressure at A is 10 kPa, and at B it is 98.1 kPa. Then the flow in the pipe is (a) upward, (b) downward, or (c) no flow. (Hint: See problem 7.23.)
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Chapter 7: Problem 7 Engineering Fluid Mechanics 10
Determine the discharge in the pipe and the pressure at point B. Neglect head losses. Assume a = 1.0 al all locations.
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Chapter 7: Problem 7 Engineering Fluid Mechanics 10
A pipe drains a tank as shown. If x = 14 ft,y =4 ft, and head losses are neglected, what is the pressure at point A and what is the velocity at the exit? Assume a = 1.0 at all locations.
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Chapter 7: Problem 7 Engineering Fluid Mechanics 10
A pipe drains a tank as shown. If x = 6 m, y = 4 m, and head losses are neglected, what is the pressure at point A and what is the velocity at the exit? Assume a = 1.0 at all locations.
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Chapter 7: Problem 7 Engineering Fluid Mechanics 10
for this system, the discharge of water is 3.5 ft3 /s, x = 1.0 m, y = 1.5 m, z = 6.0 m, and the pipe diameter is 30 em. Assuming a head loss of 0.5 m, what is the pressure head at point 2 if the jet from the nozzle is 10 em in dian1eter? Assume u = 1.0 at all locations.
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Chapter 7: Problem 7 Engineering Fluid Mechanics 10
For this diagran1 of an industrial pressure washer system,x = I ft,y = 3 ft,z = 10ft, Q = 3.5 fe/s, and the hose diameter is 4 in. Assuming a head loss of 1 ft is derived over th.e distance from point 2 to the jet, what is the pressure at point 2 if the jet from the nozzle is l-in in diameter? Assume a = 1.0 throughout.
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Chapter 7: Problem 7 Engineering Fluid Mechanics 10
Gasoline having a specific gravity of 0.8 is flowing in the pipe shown at a rate of 5 cfs. What is the pressure at section 2 when the pressure at section 1 is 18 psig and the head loss is 6 ft between the two sections? Assume a = 1.0 at all local ions.
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Chapter 7: Problem 7 Engineering Fluid Mechanics 10
Water llows from a pressurized lank as shown. The pressure in the tank above the water surface is 100 kPa gage, and the water surface level is 8 m above the outlet. The water exit velocity is 10 m/s. The head loss in I he system varies as hL = KL V2 /2g, where KL is the minor-loss coefficient. Find the value for K1 Assume a = 1.0 at all locations.
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Chapter 7: Problem 7 Engineering Fluid Mechanics 10
A reservoir with water is pressurized as shown. The pipe diameter is 1 in. The head loss in the system is given by hL = 5V2 /2g.The height between the water surface and the pipe outlet is 10ft. A discharge of 0.10 ft3 /s is needed. What must the pressure in the tank be to achieve such a flow rate? Assume a = 1.0 at all locations.
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Chapter 7: Problem 7 Engineering Fluid Mechanics 10
In the figure shown, suppose that the reservoir is open to the atmosphere at the top. The valve is used to control the flow rate from the reservoir. The head loss across the valve is given as Jr1 = 4 V2 12g, where Vis the velocity in the pipe. 1he cross-sectional area of the pipe is 8 cm2 The head loss due to friction in the pipe is negligible. 'lbe elevation of the water level in the reservoir above the pipe outlet is 9 m. Find the discharge in the pipe. Assume a = 1.0 at all locations.
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Chapter 7: Problem 7 Engineering Fluid Mechanics 10
A minor artery in the human arm, diameter D = 3 mm, tapers gradually over a distance of 20 em to a diameter of d = 1.6 mm. The blood pressure at Dis 110 mm Hg, and at d is 85 mm Hg. What is the head loss (m) that occurs over this 20-cm distance if the blood (S = 1.06) is moving with a flowrate of 300 milliliters/min, and the arm is being held horizontally? Idealize the flow in the artery as steady, the fluid as Newtonian, and the walls of the artery as rigid.
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Chapter 7: Problem 7 Engineering Fluid Mechanics 10
As shown, a microchannel is being designed to transfer fluid in a MEMS (microelectrical mechanical system) application. The channel is 200 micrometers in diameter and is 5 em long. Ethyl alcohol is driven through the system at the rate of 0.1 microliters/s (f.LL/S) with a syringe pump, which is essentially a moving piston. The pressure at the exit of the channel is atmospheric. The flow is laminar, so a = 2. The head loss in the channel is given by 32f.LLV h, = --- -yD2 where L is the channel length, D the diameter, V the mean velocity, fl. the viscosity of the fluid, and 'Y the specific weight of the fluid. Find the pressure in the syringe pump. The velocity head associated with the motion of the piston in the syringe pump is negligible.
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Chapter 7: Problem 7 Engineering Fluid Mechanics 10
Firefighting equipment requires that the exit velocity of the firehose be 30m/sat an elevation of 45 m above the hydrant. The nozzle at the end of the hose has a contraction ratio of 4:1 (A,/Ahose = 1/4). The head loss in the hose is 8V2 /2g, where V is the velocity in the hose. What must the pressure be at the hydrant to meet this requirement? The pipe supplying the hydrant is much larger than the firehose.
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Chapter 7: Problem 7 Engineering Fluid Mechanics 10
The discharge in the siphon is 2.80 cfs, D = 8 in., L1 = 3 ft, and L2 = 3 ft. Determine the head loss between the reservoir surface and point C. Determine the pressure at point B if three-quarters of the head loss (as found above) occurs between the reservoir surface and point B. Assume a = 1.0 at all locations.
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Chapter 7: Problem 7 Engineering Fluid Mechanics 10
For this siphon the elevations at A, B, C, and D are 30 m, 32m, 27m, and 26m, respectively. The head loss between the inlet and point B is three-quarters of the velocity head, and the head loss in the pipe itself between point Band the end of the pipe is one-quarter of the velocity head. For these conditions, what is the discharge and what is the pressure at point B? The pipe diameter = 25 em. Assume a = 1.0 at all locations.
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Chapter 7: Problem 7 Engineering Fluid Mechanics 10
In this system,d = 6 in., D = 12 in . 1 = 6ft. and .iz2 = 12ft. The discharge of water in the system is 10 cfs. Is the machine a pump or a turbine? What are the pressures at points A and B? Neglect head losses. Assume a = 1.0 at all locations.
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Chapter 7: Problem 7 Engineering Fluid Mechanics 10
The pipe diameter Dis 30 em, dis 15 em, and the atmospheric pressure is 100 kPa. What is the maximum allowable discharge before cavitation occurs at the throat of the venturi meter if H = 5 m? Assume a = 1.0 at all locations.
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Chapter 7: Problem 7 Engineering Fluid Mechanics 10
In this system d = IS em, D = 35 em, and the head loss from the venturi meter to the end of the pipe is given by hL = 1.5 V2 /2g, where Vis the velocity in the pipe. Neglecting all other head losses, determine what head H will first initiate cavitation if the atmospheric pressure is I 00 kPa absolute. What will be the discharge at incipient cavitation? Assume ex = 1.0 at all locations.
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Chapter 7: Problem 7 Engineering Fluid Mechanics 10
A pump is used to fill a tank 5 m in diameter from a river as shown. The water surface in the river is 2 m below the bottom of the tank. The pipe diameter is 5 em, and the head loss in the pipe is given by hr = 10 V2 /2g, where Vis the mean velocity in the pipe. The flow in the pipe is turbulent, so a = 1. The head provided by the pump varies with discharge through the pump as hp = 20 - 4 X 104 Q2 , where the discharge is given in cubic meters per second (m3 /s) and hp is in meters. How long will it take to fill the tank to a depth of 10m?
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Chapter 7: Problem 7 Engineering Fluid Mechanics 10
A pump is used to transfer SAE-30 oil from tank A to tank Bas shown. The tanks have a diameter of 12m. The initial depth of the oil in tank A is 20m, and in tank B the depth is I m. The pump delivers a constant head of 60 m. The connecting pipe has a diameter of 20 em, and the head loss due to friction in the pipe is 20 V1 /2g. Find the time required to transfer the oil from tank A to B; that is, the time required to fill tank B to 20m depth.
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Chapter 7: Problem 7 Engineering Fluid Mechanics 10
A pump is used to pressurize a tank to 300 kPa abs. The tank has a diameter of 2 m and a height of 4 m. The initial level of water in the tank is 1 m, and the pressure at the water surface is 0 kPa gage. The atmospheric pressure is 100 kPa. 1be pump operates with a constant head of 50 m. The water is drawn from a source that is 4 m below the tank bottom. The pipe connecting the source and the tank is 4 em in diameter and the head loss, including the expansion loss at the tank, is 10 V2 !2g. The flow is turbulent. Assume the compression of the air in the tank takes place isothermally, so the tank pressure is given by 3 Pr = 4 _ z/o where z, is the depth of fluid in the tank in meters. Write a computer program that will show how the pressure varies in the tank with time, and find the time to pressurize the tank to 300 kPa abs.
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Chapter 7: Problem 7 Engineering Fluid Mechanics 10
As shown, water at l5C is flowing in a 15-cm-diameter by 60-m-long run of pipe that is situated horizontally. The mean velocity is 2 m/s, and the head loss is 2m. Determine the pressure drop and the required pumping power to overcome head loss in the pipe.
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Chapter 7: Problem 7 Engineering Fluid Mechanics 10
The pump shown in the figure supplies energy to the flow such that the upstream pressure {12 in. pipe) is 5 psi and the downstream pressure (6 in. pipe) is 55 psi when the flow of water is 3.0 cfs. What horsepower is delivered by the pump to the flow? Assume a. = 1.0 at all locations.
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Chapter 7: Problem 7 Engineering Fluid Mechanics 10
A water discharge of 8m3 /sis to flow through this horizontal pipe, which is 1 m in diameter. If the head loss is given as 7 V2 /2g (Vis velocity in the pipe), how much power will have to be supplied to the flow by the pump to produce this discharge? Assume a. = 1.0 at all locations.
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Chapter 7: Problem 7 Engineering Fluid Mechanics 10
Neglecting head losses, determine what horsepower the pump must deliver to produce the flow as shown. Here the elevations at points A, B, C, and Dare 117ft, 154 ft,llO ft. and 90ft. respectively. The nozzle area is 0.10 ft 2
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Chapter 7: Problem 7 Engineering Fluid Mechanics 10
Neglecting head losses, determine what power the pump must deliver to produce the flow as shown. Here the elevations at points A, B. C, and D are 40 m, 65 m, 35 m, and 30 m, respectively. The nozzle area is 25 cm2
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Chapter 7: Problem 7 Engineering Fluid Mechanics 10
Water (10C) is flowing at a rate of 0.35 m3 /s, and it is assumed that hL = 2 V2 /2g from the reservoir to the gage, where Vis the velocity in the 30-cm pipe. What power must the pump supply? Assume a = 1.0 at all locations.
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Chapter 7: Problem 7 Engineering Fluid Mechanics 10
In the pump test shown, the rate of flow is 6 cfs of oil (S = 0.88). Calculate the horsepower that the pump supplies to the oil if there is a differential reading of 46 in. of mercury in the U-tube manometer. Assume a = 1.0 at all locations.
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Chapter 7: Problem 7 Engineering Fluid Mechanics 10
If the discharge is 500 cfs, what power output may be expected from the turbine? Assume that the turbine efficiency is 90% and that the overall head loss is 1.5 V2 12g, where Vis the velocity in the 7 ft penstock Assume a = 1.0 at all locations.
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Chapter 7: Problem 7 Engineering Fluid Mechanics 10
A small-scale hydraulic power system is shown. The elevation difference between the reservoir water surface and the pond water surface downstream of the reservoir, H, is 24m. The velocity of the water exhausting into the pond is 7 m/s, and the discharge through the system is 4 m3 /s. The head loss due to friction in the penstock (inlet pipe to turbine, under very high pressure) is negligible. Find the power produced by the turbine in kilowatts.
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Chapter 7: Problem 7 Engineering Fluid Mechanics 10
A fan produces a pressure rise of 6 mm of water to move air through a hair dryer. The mean velocity of the air at the exit is 10 m/s, and the exit diameter is 44 mm. Estimate the electrical power in watts that needs to be supplied to operate the fan. Assume that the fan/motor combination has an efficiency of 60%.
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Chapter 7: Problem 7 Engineering Fluid Mechanics 10
An engineer is making an estimate for a home owner. This owner has a small stream (Q = 1.4 cfs, T = 40F) that is located at an elevation H = 34 ft above the owner's residence. The owner is proposing to dam the stream, diverting the flow through a pipe (penstock). This flow will spin a hydraulic turbine, which in turn will drive a generator to produce electrical power. Estimate the maximum power in kilowatts that can be generated if there is no head loss and both the turbine and generator are 100% efficient. Also, estimate the power if the head loss is 5.5 ft, the turbine is 70% efficient, and the generator is 90% efficient.
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Chapter 7: Problem 7 Engineering Fluid Mechanics 10
The pump shown draws water through an 8 in. suction pipe and discharges it through a 6 in. pipe in which the velocity is 12 ft/s. The 6 in. pipe discharges horizontally into air at C. To what height h above the water surface at A can the water be raised if 17 hp is used by the pump? The pump operates at 60% efficiency and that the head loss in the pipe between A and Cis equal to 2 ~/2g. Assume ex = 1.0 throughout.
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Chapter 7: Problem 7 Engineering Fluid Mechanics 10
A pumping system is to be designed to pump crude oil a distance of 1 mile in a 1 foot-diameter pipe at a rate of 3500 gpm. The pressures at the entrance and exit of the pipe are atmospheric, and the exit of the pipe is 200 feet higher than the entrance. The pressure loss in the system due to pipe friction is 60 psi. The specific weight of the oil is 53 lbf/frl. Find the power, in horsepower, required for the pump.
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Chapter 7: Problem 7 Engineering Fluid Mechanics 10
How is the energy equation {7.29) on p. 262 of 7.3 similar to the Bernoulli equation? How is it different? Give three important similarities and three important differences.
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Chapter 7: Problem 7 Engineering Fluid Mechanics 10
What is the head loss at the outlet of the pipe that discharges water into the reservoir at a rate of I 0 cfs if the diameter of the pipe is 12 in.?
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Chapter 7: Problem 7 Engineering Fluid Mechanics 10
What is the head loss at the outlet of the pipe that discharges water into the reservoir at a rate ofO.S m3 /s if the diameter of the pipe is 50 em?
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Chapter 7: Problem 7 Engineering Fluid Mechanics 10
A 7 cm pipe carries water with a mean velocity of2 m/s. If this pipe abruptly expands to a 15 em pipe, what will be the head loss due to the abrupt expansion?
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Chapter 7: Problem 7 Engineering Fluid Mechanics 10
A 6 in. pipe abruptly expands to a 12 in. size. If the discharge of water in the pipes is 5 cfs, what is the head loss due to abrupt expansion?
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Chapter 7: Problem 7 Engineering Fluid Mechanics 10
Water is draining from tank A to tank B. The elevation difference between the two tanks is 10m. The pipe connecting the two tanks has a sudden-expansion section as shown. The cross-sectional area of the pipe from A is 8 cm2 , and the area of the pipe into B is 25 cm2 Assume the head loss in the system consists only of that due to the sudden-expansion section and the loss due to flow into tank B. Find the discharge between the two tanks.
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Chapter 7: Problem 7 Engineering Fluid Mechanics 10
A 40 em pipe abruptly expands to a 60 em size. These pipes are horizontal, and the discharge of water from the smaller size to the larger is 1.0 m3 /s. What horizontal force is required to hold the transition in place if the pressure in the 40 em pipe is 70 kPa gage? Also, what is the head loss? Assume ex = 1.0 at all locations.
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Chapter 7: Problem 7 Engineering Fluid Mechanics 10
Water ('y = 62.4lbf/ft3 ) flows through a horizontal constant diameter pipe with a cross-sectional area of 9 in2 The velocity in the pipe is IS ft/s, and the water discharges to the atmosphere. The head loss between the pipe joint and the end of the pipe is 3 ft. Find the force on the joint to hold the pipe. The pipe is mounted on frictionless rollers. Assume ex = 1.0 at all locations.
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Chapter 7: Problem 7 Engineering Fluid Mechanics 10
This rough aluminum pipe is 6 in. in diameter. It weighs 1.5 lb per foot of length, and the length L is 50 ft. If the discharge of water is 6 cfs and the head loss due to friction from section 1 to the end of the pipe is 10ft, what is the longitudinal force transmitted across section 1 through the pipe wall?
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Chapter 7: Problem 7 Engineering Fluid Mechanics 10
Water flows in this bend at a rate of 5 m3 /s, and the pressure at the inlet is 650 kPa.lf the head loss in the bend is 10m, what will the pressure be at the outlet of the bend? Also estimate the force of the anchor block on the bend in the x direction required to hold the bend in place. Assume a = 1.0 at all locations.
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Chapter 7: Problem 7 Engineering Fluid Mechanics 10
In a local water treatment plant, water flows in this bend at a rate of 7 m3/s, and the pressure at the inlet is 800 kPa. If the head loss in the bend is 13 m, what will the pressure be at the outlet of the bend? Also estimate the force of the anchor block on the bend in the x direction required to hold the bend in place. Assume a = 1.0 at all locations.
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Chapter 7: Problem 7 Engineering Fluid Mechanics 10
Fluid flowing along a pipe of diameter D accelerates around a disk of diameter d as shown in the figure. The velocity far upstream of the disk is U, and the fluid density is p. Assuming incompressible flow and that the pressure downstream of the disk is the same as that at the plane of separation, develop an expression for the force required to hold the disk in place in terms of U. D, d, and p. Using the expression you developed, determine the force when U = 10 m/s, D = 5 em, d = 4 em, and p = 1.2 kg/m3 Assume a = 1.0 at all locations.
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Chapter 7: Problem 7 Engineering Fluid Mechanics 10
port (b) only Using Section 7.8 and other resources, answer the following questions. Strive for depth, clarity, and accuracy while also combining sketches, words, and equations in ways that enhance the effectiveness of your communication. a. What are three important reasons that engineers use the HGL and the EGL? b. What factors influence the magnitude of the HGL? What factors influence the magnitude of the EGL? c. How are the EGL and HGL related to the piezometer? To the stagnation tube? d. How is the EGL related to the energy equation? e. How can you use an HGL or an EGL to determine the direction of flow?
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Chapter 7: Problem 7 Engineering Fluid Mechanics 10
The energy grade line for steady flow in a uniformdiameter pipe is shown. Which of the following could be in the "black box"? (a) a pump, (b) a partially closed valve, (c) an abrupt expansion, or (d) a turbine. Choose all valid answer(s) and state your rationale.
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Chapter 7: Problem 7 Engineering Fluid Mechanics 10
If the pipe shown has constant diameter, is this type of HGL possible? If so, under what additional conditions? If not, why not?
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Chapter 7: Problem 7 Engineering Fluid Mechanics 10
For the system shown, a. What is the flow direction? b. What kind of machine is at A? c. Do you think both pipes, AB and CA, are the same diameter? d. Sketch in the EGL for the system. e. Is there a vacuum at any point or region of the pipes? If so, identify the location.
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Chapter 7: Problem 7 Engineering Fluid Mechanics 10
The HGL and the EGL are as shown for a certain flow system. a. Is flow from A toE or from E to A? b. Does it appear that a reservoir exists in the system? c. Does the pipe atE have a uniform or a variable diameter? d. Is there a pump in the system? e. Sketch the physical setup that could yield the conditions shown between C and D. f. Is anything else revealed by the sketch?
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Chapter 7: Problem 7 Engineering Fluid Mechanics 10
The HGL and the EGL for a pipeline are shown in the figure. a. Indicate which is the HGL and which is the EGL. b. Are all pipes the same size? If not, which is the smallest? c. Is there any region in the pipes where the pressure is below atmospheric pressure? If so, where? d. Where is the point of maximum pressure in the system? e. Where is the point of minimum pressure in the system?f. What do you think is located at the end of the pipe at pointE? g. Is the pressure in the air in the tank above or below atmospheric pressure? h. What do you think is located at point B?
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Chapter 7: Problem 7 Engineering Fluid Mechanics 10
Assume that the head loss in the pipe is given by hL = 0.0 14(L/ D)( V2 /2g), where L is the length of pipe and Dis the pipe diameter. Assume a= 1.0 at all locations. a. Determine the discharge of water through this system. b. Draw the HGL and the EGL for the system. c. Locate the point of maximum pressure. d. Locate the point of minimum pressure. e. Calculate the maximum and minimum pressures in the system.
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Chapter 7: Problem 7 Engineering Fluid Mechanics 10
Sketch the HGL and the EGL for the reservoir and pipe of Example 7.2.
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Chapter 7: Problem 7 Engineering Fluid Mechanics 10
The discharge of water through this turbine is 1000 cfs. What power is generated if the turbine efficiency is 85% and the total head loss is 4ft? H = 100ft. Also, carefully sketch the EGL andtheHGL.
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Chapter 7: Problem 7 Engineering Fluid Mechanics 10
Water flows from the reservoir through a pipe and then discharges from a nozzle as shown. The head loss in the pipe itself is given as hL = 0.025(LID)(V2 /2g), where Land Dare the length and diameter of the pipe and Vis the velocity in the pipe. What is the discharge of water? Also draw the HGL and EGL for the system. Assume a = 1.0 at all locations.
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Chapter 7: Problem 7 Engineering Fluid Mechanics 10
Refer to Fig. 7.15 on p. 275 of 7.8. Assume that the head loss in the pipes is given by h1 = 0.02(L!D)(V2 /2g), where Vis the mean velocity in the pipe, Dis the pipe diameter, and Lis the pipe length. The water surface elevations of the upper and lower reservoirs are 100m and 70 m, respectively.1he respective dimensions for upstream and downstream pipes are D. = 30 em, and L. = 200m, and Dd = IS em, and Ld = 100 m. Determine the discharge of water in the system.
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Chapter 7: Problem 7 Engineering Fluid Mechanics 10
What horsepower must be supplied to the water to pump 3.0 cfs at 68F from the lower to the upper reservoir? Assume that the head loss in the pipes is given by hL = 0.018(LID)(V2 /2g), where Lis the length of the pipe in feet and Dis the pipe diameter in feet. Sketch the HGL and the EGL.
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Chapter 7: Problem 7 Engineering Fluid Mechanics 10
Water flows from reservoir A to reservoir B. The water temperature in the system is l0C, the pipe diameter D is I m, and the pipe length Lis 300m. If H = 16m, h = 2m, and the pipe head loss is given by hL = 0.01(L/D)(V2 /2g), where Vis the velocity in the pipe, what will be the discharge in the pipe? ln your solution, include the head loss at the pipe outlet, and sketch the HGL and the EGL. What will be the pressure at point P halfway between the two reservoirs? Assume a = 1.0 at all locations.
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Chapter 7: Problem 7 Engineering Fluid Mechanics 10
Water flows from reservoir A to reservoir Bin a desert retirement community. The water temperature in the system is I 00F, the pipe diameter D is 4 ft, and the pipe length L is 200 ft. If H = 35ft, h = 10ft, and the pipe head loss is given by hL = O.Ol(L/D)(V2 /2g), where Vis the velocity in the pipe, what will be the discharge in the pipe? In your solution, include the head loss at the pipe outlet. What will be the pressure at point P halfway between the two reservoirs? Assume a = 1.0 at all locations.
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Chapter 7: Problem 7 Engineering Fluid Mechanics 10
What power is required to pump water at a rate of 3 m3 /s from the lower to the upper reservoir? Assume the pipe head loss is given by hL = 0.018(LID)(V2 12g), where Lis the length of pipe, Dis the pipe diameter, and Vis the velocity in the pipe. "!he water temperature is l0C, the water surface elevation in the lower reservoir is 150 m, and the surface elevation in the upper reservoir is 250m. The pump elevation is 100 m,L1 = 100m, L2 = 1000 m, D1 = 1 m, and D2 = 50 em. Assume the pump and motor efficiency is 74%. In your solution, include the head loss at the pipe outlet and sketcl1 the HGL and the EGL. Assume a = 1.0 at all locations.
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Chapter 7: Problem 7 Engineering Fluid Mechanics 10
Refer to Fig. 7.16 on p. 276 of 7.8. Assume that the head loss in the pipe is given by h1 = 0.02(LID)(V2 !2g), where Vis the mean velocity in the pipe, D is the pipe diameter, and L is the pipe length. The elevations of the reservoir water surface, the highest point in the pipe, and the pipe outlet are 250 m, 250 m, and 210 m, respectively. The pipe diameter is 30 em, and the pipe length is 200 m. Determine the water discharge in the pipe, and, assuming that the highest point in the pipe is halfway along the pipe, determine the pressure in the pipe at tl1at point. Assume a = 1.0 at all locations.
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