Thermodynamics: An Engineering Approach
9th Edition
ISBN: 9781259822674
Author: Yunus A. Cengel Dr., Michael A. Boles
Publisher: McGraw-Hill Education
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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.
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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
Thermodynamics: An Engineering Approach
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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? 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