CONNECT FOR THERMODYNAMICS: AN ENGINEERI
9th Edition
ISBN: 9781260048636
Author: CENGEL
Publisher: MCG
expand_more
expand_more
format_list_bulleted
Concept explainers
Videos
Textbook Question
Chapter 2.8, Problem 74P
A wind turbine is rotating at 15 rpm under steady winds flowing through the turbine at a rate of 42,000 kg/s. The tip velocity of the turbine blade is measured to be 250 km/h. If 180 kW power is produced by the turbine, determine (a) the average velocity of the air and (b) the conversion efficiency of the turbine. Take the density of air to be 1.31 kg/m3.
Expert Solution & Answer
Want to see the full answer?
Check out a sample textbook solution
Students have asked these similar questions
A site is being considered for wind power generation. At this site, the wind blows steadily at 9 m/s for 2,579 hours per year. Assuming the wind velocity is negligible at other times for simplicity, determine the kWh/year that can be produced at the site for a turbine with a mechanical efficiency of 100% and an effective flow area of 5 m2. Use a value of 1.25 kg/m3 for the density of the air. Give your answer in killowatt-hours per year (kWh/year).
Hint: I reccomend starting by finding the kinetic energy (kJ/kg) of the wind.
Hint 2: Multiply the power generation (kW) by the number of hours of wind per year (h/year) to get kWh/year.
At a certain location, wind is blowing steadily at 9 m/s. Determine the mechanical energy of air per unit mass and the power
generation potential of a wind turbine with 80-m-diameter blades at that location. Also, determine the actual electric power
generation, assuming an overall efficiency of 30 percent. Take the air density to be 1.25 kg/m³.
The mechanical energy of air per unit mass is
The power generation potential of the wind turbine is
The actual electric power generation is
kW.
1kJ/kg.
kW.
Consider a wind turbine that is situated in an area that has steady winds. The
turbine rotates at 16 RPM. The mass flow rate through the turbine is 41,025 kg/s.
The tip velocity is 260 km/hr. Take the air density to be 1.31 kg/m² and assume
180kW of electric power is generated by the turbine. Determine the following:
a. Average velocity of the air
b. The efficiency of the turbine
c. Assuming winds are steady for 95% of the year, is this a suitable location
for a wind turbine? Explain.
Chapter 2 Solutions
CONNECT FOR THERMODYNAMICS: AN ENGINEERI
Ch. 2.8 - What is the difference between the macroscopic and...Ch. 2.8 - What is total energy? Identify the different forms...Ch. 2.8 - List the forms of energy that contribute to the...Ch. 2.8 - How are heat, internal energy, and thermal energy...Ch. 2.8 - What is mechanical energy? How does it differ from...Ch. 2.8 - Portable electric heaters are commonly used to...Ch. 2.8 - Natural gas, which is mostly methane CH4, is a...Ch. 2.8 - Consider the falling of a rock off a cliff into...Ch. 2.8 - Electric power is to be generated by installing a...Ch. 2.8 - The specific kinetic energy of a moving mass is...
Ch. 2.8 - Determine the specific kinetic energy of a mass...Ch. 2.8 - Calculate the total potential energy, in Btu, of...Ch. 2.8 - Determine the specific potential energy, in kJ/kg,...Ch. 2.8 - An object whose mass is 100 kg is located 20 m...Ch. 2.8 - A water jet that leaves a nozzle at 60 m/s at a...Ch. 2.8 - Consider a river flowing toward a lake at an...Ch. 2.8 - At a certain location, wind is blowing steadily at...Ch. 2.8 - What is the caloric theory? When and why was it...Ch. 2.8 - In what forms can energy cross the boundaries of a...Ch. 2.8 - What is an adiabatic process? What is an adiabatic...Ch. 2.8 - When is the energy crossing the boundaries of a...Ch. 2.8 - Consider an automobile traveling at a constant...Ch. 2.8 - A room is heated by an iron that is left plugged...Ch. 2.8 - A room is heated as a result of solar radiation...Ch. 2.8 - A gas in a pistoncylinder device is compressed,...Ch. 2.8 - A small electrical motor produces 5 W of...Ch. 2.8 - A car is accelerated from rest to 85 km/h in 10 s....Ch. 2.8 - A construction crane lifts a prestressed concrete...Ch. 2.8 - Determine the torque applied to the shaft of a car...Ch. 2.8 - A spring whose spring constant is 200 lbf/in has...Ch. 2.8 - How much work, in kJ, can a spring whose spring...Ch. 2.8 - A ski lift has a one-way length of 1 km and a...Ch. 2.8 - The engine of a 1500-kg automobile has a power...Ch. 2.8 - A damaged 1200-kg car is being towed by a truck....Ch. 2.8 - As a spherical ammonia vapor bubble rises in...Ch. 2.8 - A steel rod of 0.5 cm diameter and 10 m length is...Ch. 2.8 - What are the different mechanisms for transferring...Ch. 2.8 - For a cycle, is the net work necessarily zero? For...Ch. 2.8 - On a hot summer day, a student turns his fan on...Ch. 2.8 - Water is being heated in a closed pan on top of a...Ch. 2.8 - An adiabatic closed system is accelerated from 0...Ch. 2.8 - A fan is to accelerate quiescent air to a velocity...Ch. 2.8 - A vertical pistoncylinder device contains water...Ch. 2.8 - At winter design conditions, a house is projected...Ch. 2.8 - A water pump increases the water pressure from 15...Ch. 2.8 - The lighting needs of a storage room are being met...Ch. 2.8 - A university campus has 200 classrooms and 400...Ch. 2.8 - Consider a room that is initially at the outdoor...Ch. 2.8 - An escalator in a shopping center is designed to...Ch. 2.8 - Consider a 2100-kg car cruising at constant speed...Ch. 2.8 - Prob. 51PCh. 2.8 - What is mechanical efficiency? What does a...Ch. 2.8 - How is the combined pumpmotor efficiency of a pump...Ch. 2.8 - Can the combined turbinegenerator efficiency be...Ch. 2.8 - Consider a 2.4-kW hooded electric open burner in...Ch. 2.8 - The steam requirements of a manufacturing facility...Ch. 2.8 - Reconsider Prob. 256E. Using appropriate software,...Ch. 2.8 - A 75-hp (shaft output) motor that has an...Ch. 2.8 - Prob. 59PCh. 2.8 - An exercise room has six weight-lifting machines...Ch. 2.8 - A room is cooled by circulating chilled water...Ch. 2.8 - The water in a large lake is to be used to...Ch. 2.8 - A 7-hp (shaft) pump is used to raise water to an...Ch. 2.8 - A geothermal pump is used to pump brine whose...Ch. 2.8 - At a certain location, wind is blowing steadily at...Ch. 2.8 - Reconsider Prob. 265. Using appropriate software,...Ch. 2.8 - Water is pumped from a lower reservoir to a higher...Ch. 2.8 - An 80-percent-efficient pump with a power input of...Ch. 2.8 - Water is pumped from a lake to a storage tank 15 m...Ch. 2.8 - Large wind turbines with a power capacity of 8 MW...Ch. 2.8 - A hydraulic turbine has 85 m of elevation...Ch. 2.8 - The water behind Hoover Dam in Nevada is 206 m...Ch. 2.8 - An oil pump is drawing 44 kW of electric power...Ch. 2.8 - A wind turbine is rotating at 15 rpm under steady...Ch. 2.8 - How does energy conversion affect the environment?...Ch. 2.8 - What is acid rain? Why is it called a rain? How do...Ch. 2.8 - Why is carbon monoxide a dangerous air pollutant?...Ch. 2.8 - What is the greenhouse effect? How does the excess...Ch. 2.8 - What is smog? What does it consist of? How does...Ch. 2.8 - Consider a household that uses 14,000 kWh of...Ch. 2.8 - When a hydrocarbon fuel is burned, almost all of...Ch. 2.8 - Prob. 82PCh. 2.8 - A typical car driven 20,000 km a year emits to the...Ch. 2.8 - Prob. 84PCh. 2.8 - What are the mechanisms of heat transfer?Ch. 2.8 - Which is a better heat conductor, diamond or...Ch. 2.8 - How does forced convection differ from natural...Ch. 2.8 - What is a blackbody? How do real bodies differ...Ch. 2.8 - Define emissivity and absorptivity. What is...Ch. 2.8 - Does any of the energy of the sun reach the earth...Ch. 2.8 - The inner and outer surfaces of a 5-m 6-m brick...Ch. 2.8 - The inner and outer surfaces of a 0.5-cm-thick 2-m...Ch. 2.8 - Reconsider Prob. 292. Using appropriate software,...Ch. 2.8 - Prob. 94PCh. 2.8 - Prob. 95PCh. 2.8 - Prob. 96PCh. 2.8 - Prob. 97PCh. 2.8 - For heat transfer purposes, a standing man can be...Ch. 2.8 - Prob. 99PCh. 2.8 - Prob. 100PCh. 2.8 - A 1000-W iron is left on the ironing board with...Ch. 2.8 - A 7-cm-external-diameter, 18-m-long hot-water pipe...Ch. 2.8 - A thin metal plate is insulated on the back and...Ch. 2.8 - Reconsider Prob. 2103. Using appropriate software,...Ch. 2.8 - The outer surface of a spacecraft in space has an...Ch. 2.8 - Prob. 106PCh. 2.8 - A hollow spherical iron container whose outer...Ch. 2.8 - Some engineers have developed a device that...Ch. 2.8 - Consider a classroom for 55 students and one...Ch. 2.8 - Consider a homeowner who is replacing his...Ch. 2.8 - Prob. 111RPCh. 2.8 - The U.S. Department of Energy estimates that...Ch. 2.8 - A typical household pays about 1200 a year on...Ch. 2.8 - Prob. 114RPCh. 2.8 - Prob. 115RPCh. 2.8 - Prob. 116RPCh. 2.8 - Consider a TV set that consumes 120 W of electric...Ch. 2.8 - Water is pumped from a 200-ft-deep well into a...Ch. 2.8 - Consider a vertical elevator whose cabin has a...Ch. 2.8 - Prob. 120RPCh. 2.8 - In a hydroelectric power plant, 65 m3/s of water...Ch. 2.8 - The demand for electric power is usually much...Ch. 2.8 - The pump of a water distribution system is powered...Ch. 2.8 - Prob. 124RPCh. 2.8 - A 2-kW electric resistance heater in a room is...Ch. 2.8 - Prob. 126FEPCh. 2.8 - A 75-hp compressor in a facility that operates at...Ch. 2.8 - On a hot summer day, the air in a well-sealed room...Ch. 2.8 - A fan is to accelerate quiescent air to a velocity...Ch. 2.8 - A 900-kg car cruising at a constant speed of 60...Ch. 2.8 - Prob. 131FEPCh. 2.8 - Prob. 132FEPCh. 2.8 - A 2-kW pump is used to pump kerosene ( = 0.820...Ch. 2.8 - Prob. 134FEPCh. 2.8 - Prob. 135FEPCh. 2.8 - Prob. 136FEPCh. 2.8 - Prob. 137FEPCh. 2.8 - Heat is transferred steadily through a...Ch. 2.8 - The roof of an electrically heated house is 7 m...
Additional Engineering Textbook Solutions
Find more solutions based on key concepts
What parts are included in the vehicle chassis?
Automotive Technology: Principles, Diagnosis, And Service (6th Edition) (halderman Automotive Series)
For the beam loading of Figure P334, draw the complete shearing force and bending moment diagrams, and determin...
Machine Elements in Mechanical Design (6th Edition) (What's New in Trades & Technology)
A 20-lb force is applied to the control rod AB as shown. Knowing that the length of the rod is 9 in. and that t...
Statics and Mechanics of Materials
A nozzle at A discharges water with an initial velocity of 36 ft/s at an angle with the horizontal. Determine ...
Vector Mechanics for Engineers: Dynamics
List several uses of the arbor press.
Machine Tool Practices (10th Edition)
Compute the hydraulic radius for a circular drain pipe running half full if its inside diameter is 300 mm.
Applied Fluid Mechanics (7th Edition)
Knowledge Booster
Learn more about
Need a deep-dive on the concept behind this application? Look no further. Learn more about this topic, mechanical-engineering and related others by exploring similar questions and additional content below.Similar questions
- A fan is powered by a 0.5-hp motor and delivers air at a rate of 85 m3 /min. Determine the highest value for the average velocity of air mobilized by the fan. Take the density of air to be 1.18 kg/m3 .arrow_forwardAn air-conditioning system requires airflow at the main supply duct at a rate of 130 m3 /min. The average velocity of air in the circular duct is not to exceed 8 m/s to avoid excessive vibration and pressure drops. Assuming the fan converts 80 percent of the electrical energy it consumes into kinetic energy of air, determine the size of the electric motor needed to drive the fan and the diameter of the main duct. Take the density of air to be 1.20 kg/m3arrow_forwardAt a certain location, wind is blowing steadily at 10 m/s. Determine the mechanical energy of air per unit mass and the power generation potential of a wind turbine with 70-m-diameter blades at that location. Also determine the actual electric power generation assuming an overall efficiency of 30 percent. Take the air density to be 1.25 kg/m3.arrow_forward
- Steam flows into a turbine at the rate of 10 kg/s and 10 KW of heat are lost from the turbine. Ignoring elevation and kinetic energy effects, calculate the power output from the turbine. Given: h1 = 2739.0 kJ/kg : h2 = 2300.5 kJ/kg.arrow_forwardA mini hydro power station takes in 3 cubic meters per second of water from a wide open reservoir through its turbine from an elevation of 15 meters and discharges to its surroundings at 0.50 m/s. During data gathering, the rotational force of the turbine shaft is measured 250 N for a distance of 2 m from its center axis at 2,850 rpm. If the electrical generator is 88% efficient, determine the turbine efficiency and the electrieity output of this station. Show the energy or schematie diagram and label it accordingly.arrow_forwardA water pump increases the water pressure from 15 psia to 70 psia. Determine the power input required, in hp, to pump 0.8 ft'/s of water. Does the water temperature at the inlet have any significant effect on the required flow power?arrow_forward
- The shaft power of a turbine operating with 80 percent efficiency is 450 kW. If the mass flow rate through the turbine is 625 kg/s, the load removed from the fluid by the turbine iswhat is the amount? Take it as g=9.81 m/s2arrow_forwardA reciprocating compressor draws in 500 ftImin of air whose density is 0.079 Ibm/t° and discharges it at a density of 0.304 Ibm/t°. The pressure in the suction and discharge are 15 psia and 80 psia, respectively. The increase in the specific internal energy is 33.8 BTU/b and the heat transferred from the air by cooling is 13 BTU/lb. Determine the work in the air, in Hp.arrow_forwardAt the exhaust of a turboject engine the nozzle is operating steadily and heat loss is assumed negligible. If the specific enthalpy of fluid and velocity of fluid at the inlet are 3224 kJ/kg and 278 km/hr respectively. At the exit the specific enthalpy of fluid is 2518 J/kg. Calculate the exit area (in mm²) of the nozzle when the specific volume at the nozzle exit is 0.63 m³/kg at the inlet area of 0.21 m² and the specific volume at the inlet is 0.30 m³/kg.arrow_forward
- Air whose density is 0.082 lbm/ft3 enters the duct of an air-conditioning system at a volume flow rate of 450 ft3/min. If the diameter of the duct is 16 in, determine the velocity of the air at the duct inlet and the mass flow rate of air.arrow_forwardWater is pumped from a lake to a storage tank 15 m above at a rate of 70 L/s while consuming 15.4 kW of electric power. Disregarding any frictional losses in the pipes and any changes in kinetic energy, determine (a) the overall efficiency of the pump–motor unit and (b) the pressure difference between the inlet and the exit of the pump.arrow_forwardAn oil pump is drawing 44 kW of electric power while pumping oil with ρ = 860 kg/m3 at a rate of 0.1 m3 /s. The inlet and outlet diameters of the pipe are 8 cm and 12 cm, respectively. If the pressure rise of oil in the pump is measured to be 500 kPa and the motor efficiency is 90 percent, determine the mechanical efficiency of the pump.arrow_forward
arrow_back_ios
SEE MORE QUESTIONS
arrow_forward_ios
Recommended textbooks for you
Elements Of ElectromagneticsMechanical EngineeringISBN:9780190698614Author:Sadiku, Matthew N. O.Publisher:Oxford University Press
Mechanics of Materials (10th Edition)Mechanical EngineeringISBN:9780134319650Author:Russell C. HibbelerPublisher:PEARSON
Thermodynamics: An Engineering ApproachMechanical EngineeringISBN:9781259822674Author:Yunus A. Cengel Dr., Michael A. BolesPublisher:McGraw-Hill Education
Control Systems EngineeringMechanical EngineeringISBN:9781118170519Author:Norman S. NisePublisher:WILEY
Mechanics of Materials (MindTap Course List)Mechanical EngineeringISBN:9781337093347Author:Barry J. Goodno, James M. GerePublisher:Cengage Learning
Engineering Mechanics: StaticsMechanical EngineeringISBN:9781118807330Author:James L. Meriam, L. G. Kraige, J. N. BoltonPublisher:WILEY
Elements Of Electromagnetics
Mechanical Engineering
ISBN:9780190698614
Author:Sadiku, Matthew N. O.
Publisher:Oxford University Press
Mechanics of Materials (10th Edition)
Mechanical Engineering
ISBN:9780134319650
Author:Russell C. Hibbeler
Publisher:PEARSON
Thermodynamics: An Engineering Approach
Mechanical Engineering
ISBN:9781259822674
Author:Yunus A. Cengel Dr., Michael A. Boles
Publisher:McGraw-Hill Education
Control Systems Engineering
Mechanical Engineering
ISBN:9781118170519
Author:Norman S. Nise
Publisher:WILEY
Mechanics of Materials (MindTap Course List)
Mechanical Engineering
ISBN:9781337093347
Author:Barry J. Goodno, James M. Gere
Publisher:Cengage Learning
Engineering Mechanics: Statics
Mechanical Engineering
ISBN:9781118807330
Author:James L. Meriam, L. G. Kraige, J. N. Bolton
Publisher:WILEY
Fluid Mechanics - Viscosity and Shear Strain Rate in 9 Minutes!; Author: Less Boring Lectures;https://www.youtube.com/watch?v=_0aaRDAdPTY;License: Standard youtube license