In a Rankine cycle, superheated steam that enters the turbine at 1273.15 K and 1.8 MPa is then expanded to a vapor at 0.1 MPa. What is the shaft work generated per kilogram of steam if the efficiency of the turbine is 0.56

Respuesta :

Answer:

The shaft work generated per kilogram is [tex]-1.3 \frac{MJ}{kg}[/tex]

Explanation:

Given:

Temperature [tex]T = 1273.15[/tex] K

Initial Pressure [tex]P_{1} = 1.8[/tex] MPa

Final pressure [tex]P_{2} = 0.1[/tex] MPa

From the table superheated,

[tex]h_{i} = 4635[/tex] [tex]\frac{K J}{Kg}[/tex] and  [tex]h_{f} = 2706.54[/tex] [tex]\frac{K J}{Kg}[/tex]

Work done by shaft is,

 [tex]W = h_{f} - h_{i}[/tex]

 [tex]W = 2706.54 - 4635[/tex]

 [tex]W = -1928.46 \frac{kJ}{kg}[/tex]

But here efficiency is 0.56,

So work generated per kg is,

Work = [tex]0.56 \times(- 1928.46)[/tex]

Work = [tex]-1.3[/tex] [tex]\frac{MJ}{kg}[/tex]

Therefore, the shaft work generated per kilogram is [tex]-1.3 \frac{MJ}{kg}[/tex]