Fluid Mechanics: Fundamentals and Applications
4th Edition
ISBN: 9781259877827
Author: CENGEL
Publisher: MCG
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Chapter 5, Problem 142P
Computer-aided designs, the use of better materials, and better manufacturing techniques have resulted in a tremendous increase in the efficiency of pumps, turbines, and electric motors. Contact one or more pump, turbine, and motor manufacturers and obtain information about the efficiency of their products. In general, how does efficiency vary with rated power of these devices?
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Chapter 5 Solutions
Fluid Mechanics: Fundamentals and Applications
Ch. 5 - Does the amount of mass entering a control volume...Ch. 5 - Define mass and volume flow rates. How are they...Ch. 5 - Name four physical quantities that are conserved...Ch. 5 - When is the flow through a control volume steady?Ch. 5 - Consider a device with one inlet and one outlet....Ch. 5 - A hair dryer is basically a duct of constant...Ch. 5 - A garden hose attached with a nozzle is used to...Ch. 5 - Air whose density is 0.082 Ibm/ft3 enters the duct...Ch. 5 - A 0.7$-m3 rigid tank initially contains air whose...Ch. 5 - Consider the flow of an incompressible Newtonian...
Ch. 5 - A desktop computer is to be cooled by a fan whose...Ch. 5 - The minimum fresh air requirement of a residential...Ch. 5 - The ventilating fan of the bathroom of a building...Ch. 5 - Air enters a nozzle steadily at 2.21 kg/m3 and 20...Ch. 5 - Air at 40°C flow steadily through the pipe shown...Ch. 5 - In climates with low night-time temperatures, an...Ch. 5 - What is mechanical energy? How does it differ from...Ch. 5 - Define turbine efficiency, generator efficiency,...Ch. 5 - What is mechanical efficiency? What does a...Ch. 5 - How is the combined pump-motor efficiency of a...Ch. 5 - Prob. 21PCh. 5 - A differential thermocouple with sensors at the...Ch. 5 - Electric power is to be generated by installing a...Ch. 5 - Consider a river flowing toward a lake at an...Ch. 5 - Express the Bernoulli equation in three different...Ch. 5 - What are the three major assumptions used in the...Ch. 5 - Define static, dynamic, and hydrostatic pressure....Ch. 5 - What is streamwise acceleration? How does it...Ch. 5 - What is stagnation pressure? Explain how it can be...Ch. 5 - Define pressure head, velocity head, and elevation...Ch. 5 - How is the location of the hydraulic grade line...Ch. 5 - Prob. 33CPCh. 5 - What is the hydraulic grade line? How does it...Ch. 5 - A glass manometer with oil as the working fluid is...Ch. 5 - The velocity of a fluid flowing in a pipe is to be...Ch. 5 - The water level of a tank on a building roof is 20...Ch. 5 - Prob. 38CPCh. 5 - Prob. 39CPCh. 5 - In a hydroelectric power plant, water enters the...Ch. 5 - A Pitot-static probe is used to measure the speed...Ch. 5 - The air velocity in the duct of a heating system...Ch. 5 - A piezometer and a Pitot tube are tapped into a...Ch. 5 - The diameter of a cylindrical water tank is D0and...Ch. 5 - A siphon pumps water from a large reservoir to a...Ch. 5 - Water flows through a horizontal pipe at a rate of...Ch. 5 - An airplane is flying at an altitude of 10.500 m....Ch. 5 - While traveling on a dirt road, the bottom of a...Ch. 5 - The water in an 8-rn-diameter, 3-rn-high...Ch. 5 - Reconsider Prob. 5-49. Determine how long it will...Ch. 5 - Air at 105 kPa and 37°C flows upward through a...Ch. 5 - Water at 20°C is siphoned from a reservoir as...Ch. 5 - The water pressure in the mains of a city at a...Ch. 5 - A pressurized tank of water has a 10-cm-diameter...Ch. 5 - Air is flowing through a venturi meter whose...Ch. 5 - The water level in a tank is 20 m above the...Ch. 5 - The air velocity in a duct is measured by a...Ch. 5 - In cold climates, water pipes may freeze and burst...Ch. 5 - Prob. 61PCh. 5 - A fluid of density and viscosity flows through a...Ch. 5 - What is the minimum diameter at section (1) to...Ch. 5 - What is irreversible head loss? How is it related...Ch. 5 - What is useful pump head? How is it related to the...Ch. 5 - Consider the steady adiabatic flow of an...Ch. 5 - Consider the steady adiabatic flow of an...Ch. 5 - What is the kinetic energy correction factor? Is...Ch. 5 - The water level in a tank is 20 m above the...Ch. 5 - A 3-rn-high tank filled with water has a discharge...Ch. 5 - A person is filling a knee-high bucket with water...Ch. 5 - Tater is being pumped from a large lake to a...Ch. 5 - A 15-hp (shaft) pump is used to raise water to a...Ch. 5 - Water flows at a rate of 0.040 m3/s in a...Ch. 5 - The water level in a tank is 20 m above the...Ch. 5 - A hydraulic turbine has 50 m of head available at...Ch. 5 - In a hydroelectric power plant, water flows from...Ch. 5 - Reconsider Prob. 5-78E. Determine the flow rate of...Ch. 5 - A fan is to be selected to ventilate a bathroom...Ch. 5 - Water flows at a rate of 20 L/s through a...Ch. 5 - The water level in a tank is 34 ft above the...Ch. 5 - A large tank is initially filled with water 4 m...Ch. 5 - Water enters a hydraulic turbine through a...Ch. 5 - A 78-percent efficient 12-hp pump is pumping water...Ch. 5 - Water is pumped from a lower reservoir to a higher...Ch. 5 - Water in a partially filled large tank is to be...Ch. 5 - Underground water is to be pumped by a 78 percent...Ch. 5 - Reconsider Prob. 5-88. Determine the flow rate of...Ch. 5 - The velocity profile for turbulent flow in a...Ch. 5 - The demand for electric power is usually much...Ch. 5 - Prob. 92PCh. 5 - Consider a fully filled hemisphere shaped tank...Ch. 5 - The velocity of a liquid flowing in a circular...Ch. 5 - Air at 250 kgrn3 enters a nozzle that has an...Ch. 5 - The air in a 5m5-m3-m hospital room is to be...Ch. 5 - The water level in a tank is 70 ft above the...Ch. 5 - A pressurized 2-rn-diameter tank of water has a...Ch. 5 - Underground water is being pumped into a pool...Ch. 5 - Prob. 100PCh. 5 - A very large tank contains air at 102 kPa at a...Ch. 5 - Water is flowing through a Venturi meter whose...Ch. 5 - Water flows at a rate of 0.011 m3/s in a...Ch. 5 - Air flows through a pipe at a rate of 120 L/s. The...Ch. 5 - A 3-rn-high large tank is initially filled with...Ch. 5 - Reconsider Prob. 5-105. In order to dram the tank...Ch. 5 - A D0= 1 2-rn-diameter tank is initially filled...Ch. 5 - An oil pump is drawing 18 kW of electric power...Ch. 5 - A wind tunnel draws atmospheric air at 20°C and...Ch. 5 - Consider a spherical tank containing compressed...Ch. 5 - A tank with openings 1,2, and 3 is moving to left...Ch. 5 - Two dimensionally identical containers are...Ch. 5 - A circular thin plate is placed on the top of a...Ch. 5 - A pump-storage plant uses a turbine to generate...Ch. 5 - A diffuser in a pipe flow is basically a slow...Ch. 5 - Prob. 117PCh. 5 - Prob. 118PCh. 5 - Prob. 119PCh. 5 - Air enters a steady-flow compressor at 1 atm and...Ch. 5 - A 7$-m-high water body that is open to the...Ch. 5 - Prob. 122PCh. 5 - Prob. 123PCh. 5 - A hydraulic turbine is used to generate power by...Ch. 5 - The efficiency of a hydraulic turbine-generator...Ch. 5 - Which one is not an assumption involved with the...Ch. 5 - Consider incompressible, frictionless flow of a...Ch. 5 - Consider incompressible, frictionless flow of...Ch. 5 - Consider water flow in a piping network. The...Ch. 5 - The static and stagnation pressures of a fluid in...Ch. 5 - The static and stagnation pressures of a fluid in...Ch. 5 - The difference between the heights of energy grade...Ch. 5 - Water at 120 kPa (gage) is flowing in a horizontal...Ch. 5 - Water is withdrawn a the bottom of a large tank...Ch. 5 - Water at 80 kPa (gage) enters a horizontal pipe at...Ch. 5 - Liquid ethanol (p = 783 kg/m3) at a pressure of...Ch. 5 - Seawater is to be pumped into a large tank at a...Ch. 5 - An adiabatic pump is used to increase the pressure...Ch. 5 - The shaft power from a 90 percent-efficient...Ch. 5 - Using a 1are bucket whose volume is known and...Ch. 5 - Your company is setting up an experiment that...Ch. 5 - Computer-aided designs, the use of better...Ch. 5 - Using a handheld bicycle pump to generate an air...Ch. 5 - Using a flexible drinking straw and a ruler,...Ch. 5 - The power generated by a wind turbine is...
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- Hydro-machinery such as turbines and pumps represent fluid devices that have wide variety of configurations. Centrifugal pumps add energy to a fluid – by doing work on the fluid to move and increase the pressure. Figure 3 below shows the velocity diagram at the inlet and exit of a centrifugal pump impeller pumping water at 6000 L/min and operating at 1750 rpm. The pump has a blade height, b, of 6cm with ri = 4cm and r2 = 16cm, with an exit blade angle B2 = 22°. Assume ideal flow conditions and that the tangentia! velocity component of the water entering the blade is zero. Analyze the pump in terms of tangential velocity component at the exit Ve2, the ideal head W shaft rise hi, and the power transferred to the fluid Jaz V Figure 3arrow_forwardFor each statement, choose whether the statement is true or false, and discuss your answer briefly: (a) If the rpm of a pump is doubled, all else staying the same, the capacity of the pump goes up by a factor of about 2. (b) If the rpm of a pump is doubled, all else staying the same, the net head of the pump goes up by a factor of about 2. (c) If the rpm of a pump is doubled, all else staying the same, the required shaft power goes up by a factor of about 4. (d) If the rpm of a turbine is doubled, all else staying the same, the output shaft power of the turbine goes up by a factor of about 8.arrow_forwardGive at least two reasons why turbines often have greater efficiencies than do pumps.arrow_forward
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