Page 162 - DJJ20063- Thermodynamics 1

DJJ20063- Thermodynamics 1

SELF-ASSESSMENT

You are approaching success. Try all the questions in this self-assessment section and
check your answers with those given in the Feedback to Self-Assessment on the next

page. If you face any problem, discuss it with your lecturer. Good luck.

1. Explain why the Rankine cycle and not the Carnot cycle is taken as the ideal cycle

for steam plant. Sketch the T-s diagram for these cycles when using steam as the
working fluid.

2. What is the highest thermal efficiency possible for a Carnot cycle operating

o
o
between 210 C and 15 C.
3. A steam power plant operates between a boiler pressure of 30 bar and a
condenser pressure of 0.04 bar. Calculate for these limits the cycle efficiency, the

work ratio and the specific steam consumption for a Carnot cycle using wet steam.

4. A steam power plant operates between a boiler pressure of 30 bar and a

condenser pressure of 0.04 bar. Calculate for these limits the cycle efficiency, the
work ratio, and the specific steam consumption for a Rankine cycle with dry

saturated steam at entry to the turbine.

5. In a steam power plant, dry saturated steam enters the turbine at 47 bar and is
expanded isentropically to the condenser pressure of 0.13 bar. Determine the

Rankine cycle efficiency when

a) the feed pump work is neglected

b) the feed pump work is taken into account

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