(a)
To sketch the cycle on PV diagram.
(a)
Explanation of Solution
Introduction:
The Brayton cycle consists of various thermodynamic process, an adiabatic compression, an isobaric expansion, an adiabatic expansion and an isobaric compression.
The figure below shows the PV curve of Brayton cycle,
Figure (1)
From the range of temperature
Conclusion:
Therefore, the diagram of PV curve on Brayton cycle is shown in figure (1).
(b)
Show that the efficiency of the cycle as
(b)
Answer to Problem 83P
The efficiency of the cycle as
Explanation of Solution
Formula used:
The expression for the efficiency is,
Here, the heat absorbed from the heat reservoir during isobaric expansion is
The expression for change in enthalpy from first law of
The expression for
The expression for work done throught the cycle is,
Calculation:
The heat absorbed from the heat reservoir during isobaric expansion is calculated as,
By using the ideal gas law we get,
Similarly,
The delivered to cold reservoir during isobaric compression is calculated as
By using the ideal gas law we get
The efficiency is calculated as,
Conclusion:
Therefore, the efficiency of the cycle as
(c)
To show the efficiency is
(c)
Answer to Problem 83P
The efficiency is
Explanation of Solution
Formula used:
The expression for adiabatic process is given as,
Calculation:
The relation between pressure and temperature for adiabatic process AB is calculated as,
The relation between pressure and temperature for adiabatic process CD is calculated as,
Subtracting equation (1) with equation (2) we get,
By using efficiency from part (a) we get,
Conclusion:
Therefore, the efficiency is
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Chapter 19 Solutions
Physics for Scientists and Engineers, Vol. 3
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