Handbook of Electrical Engineering

552 HANDBOOK OF ELECTRICAL ENGINEERING

Find the following:-

1. Ideal compressor outlet temperatureT 2 in◦Kand◦C.


2. Ideal turbine outlet temperatureT 4 in◦Kand◦C.


3. Ideal cycle efficiencyηiin per unit.


4. Compressor outlet temperatureT 2 ein◦Kand◦C.


5. Turbine outlet temperatureT 4 ein◦Kand◦C due to expansion efficiencyηt.


6. Practical cycle efficiencyηpper unit, withηcandηtincluded.


7. Find the pressure ratiorpmaxthat causes the maximum power to be delivered to the generator.

F.3 Detailed Requirements

Assume the specific heats are functions of temperature and take account of the pressure dropsP 1 ,
P 23 andP 4.

Find the following:-

8. Compressor outlet temperatureT2eain◦Kand◦C, due to compression efficiencyηcand the inlet
   pressure dropP 1.


9. Turbine outlet temperatureT4eain◦Kand◦C, due to expansion efficiencyηt, the combustion
   pressure dropP 23 , and the outlet pressure dropP 4.


10. The work done on the mass flow to produce the desired output power of 12 MW.


11. Theoretical thermal efficiencyηpaper unit, with all the losses included.


12. Overall thermal efficiencyηpaowith all losses included.

F.4 Basic Solutions

Step 1. From (2.14),

δ=( 1. 0 − 1. 4 )/ 1. 4 =− 0. 2857

(P 2 /P 1 )δ= 11. 0 −^0.^2857 = 0. 50403

Therefore,

T 2 =T 1 / 0. 50403 =( 273. 0 + 20. 0 )/ 0. 50403 = 581. 31 ◦K or 308. 31 ◦C.

Step 2. From (2.15),
(P 3 /P 4 )δ= 11. 0 −^0.^2857 = 0. 50403

Therefore,

T 4 =T 3 × 0. 50403 =( 273. 0 + 950. 0 )× 0. 50403 = 616. 43 ◦K or 343. 43 ◦C.

Step 3.
rδp= 11. 0 −^0.^2857 = 0. 50403

and
rpβ= 11. 0 +^0.^2857 = 1. 984