What is the difference between flow work and boundary work?

If the boundary of the control volume is stationary, the moving boundary work is zero, and the work terms involved are shaft work and electric work. Work is needed to push the fluid into or out of the boundaries of a control volume if mass flow is involved. This work is called the flow work (flow energy).

What is shaft work measured in?

A turbine performs shaft work at a certain rate and the units of shaft work are [kJs k J s ] which is the same as kilo-Watts, [kW ]. The heat transfer rate is also measured in [kW ]. The energy content of a flowing substance is given by enthalpy.

What is shaft work and give its formula?

Rate of Shaft Work, = rate of work done by the fluid on a shaft protruding outside the C.V. E.g. a turbine (extracts energy from a flow) : The turbine takes energy from the fluid and converts it into rotation of the shaft.

Is shaft work done by system?

Shaft work is a kind of contact work, because it occurs through direct material contact with the surrounding matter at the boundary of the system. A system that is initially in a state of thermodynamic equilibrium cannot initiate any change in its internal energy.

How do shafts transmit power?

A shaft is an element used to transmit power and torque, and it can support reverse bending (fatigue). Most shafts have circular cross sections, either solid or tubular. The difference between a shaft and an axle is that the shaft rotates to transmit power, and that it is subjected to fatigue.

Is shaft work always positive?

Shaft work is a kind of contact work, because it occurs through direct material contact with the surrounding matter at the boundary of the system. Thus the sign of shaft work is always negative, work being done on the system by the surroundings.

Where is shaft used?

The term shaft usually refers to a component of circular cross-section that rotates and transmits power from a driving device, such as a motor or engine, through a machine. Shafts can carry gears, pulleys, and sprockets to transmit rotary motion and power via mating gears, belts, and chains.