Conservation of energy in a fixed volume

The energy contained in the inlet and outlet streams will exist in three forms internal energy, mu, kinetic energy, mc, and potential energy relative to a given datum, mgz, where m is the mass under consideration, c is its velocity and z is its height above the datum. 

Figur 3.1 Bounded volume with mass inflows and outflows. 

Rgure 3.2 Fixed volume receiving an inflow and outflow, subject to a heat input and doing work. 

P is the mechanical power abstracted from the fixed volume (W), 

Z2 are the heights above the datum of the inlet and outlet flows (m), 

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Hence we may set down the full form of the equation for the conservation of energy in a fixed volume as ... 

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