what is the difference between P-V work and shaft work?

Answer 1

P-V work is caused by a change in volume of a gas and the consequent movement of the system boundaries: For example you raise the pressure (and therefore volume) of a gas in a piston-cylinder set-up by heating. The piston moves upwards and work is done on the surroundings (by the system). Or you put a weight on the piston and cause it to move downwards performing work on the system.

In shaft work we have a mechanical device involved. For example a pump can perform work on a gas or a gas can perform work on a turbine by turning the turbine blades. It is called shaft work because there's usually a rotating shaft in the mechanical device.

Answer 2

Shaft Work

Answer 3

P-V as in pressure v.s. specific volume. That's a graph where pressure is a function of specific volume, the area under the curve of this plot is work. This kind of work is like cylinder or piston work, e.g. hydraulic or pneumatic lines increase/decrease volume that changes pressure and you get some work out.

Shaft work is generally rotational energy in/out, e.g. water turning a turbine to power electric generator in a hydro-electric dam. The water moves the turbine like a really fast paddle wheel, the rotation is transferred to the generator, shaft work in, which powers the generator to make electricity.

Answer 4

There are frictional losses through the gears and bearings in the real world which reduce the work from the engine to the output shaft.

Answer 5

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