Question 2.8: A piston and cylinder machine containing a fluid system has ......

Engineering Thermodynamics [1393131]

A piston and cylinder machine containing a fluid system has a stirring device in the cylinder. The piston is frictionless and it is held against the fluid due to the atmospheric pressure of 101.325 kPa.
The stirring device is turned 10,000 revolutions with an average torque against the fluid 1.275 Nm.
Meanwhile the piston of 0.6 m diameter moves out 0.8 m. Find the net work transfer for the system. (AKTU, 2013–2014)

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$W_{net} = W_{disp} – W_{stir} = \int{pdV} – 2\pi NT = p\frac{\pi }{4} d^2l – 2\pi NT = -57.2 kJ$

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