Page 154 - DJJ20063- Thermodynamics 1

DJJ20063- Thermodynamics 1

Q451

5

4 1
Boiler

Pump Turbine W12

W34 Condenser
3 2

Q23

p1

5 1
T1
p2

4

T2
3 2

s
A B
Fig 4.2.1-2 The Rankine cycle

The plant required and the numbers referring to the state points for the Rankine cycle is
shown in Fig. 4.2.1-2. The steam at the inlet to the turbine may be wet, dry saturated, or

superheated, but only the dry saturated condition is shown in Fig. 4.2.1-2. The steam

flows round the cycle and each process may be analysed using the steady flow energy

equation where changes in kinetic energy and potential energy may be neglected.

i.e. h1 + Q = h2 + W

In this statement of the equation the subscripts 1 and 2 refer to the initial and final state

points of the process; each process in the cycle can be considered in turn as follows:
Boiler:

h4 + Q451 = h1 + W

Therefore, since W = 0,

Q451 = h1 – h4 (4.13)

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