Page 560 - Handbook of Electrical Engineering

552 HANDBOOK OF ELECTRICAL ENGINEERING

Find the following:-

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1. Ideal compressor outlet temperature T 2 in Kand C.
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2. Ideal turbine outlet temperature T 4 in Kand C.
3. Ideal cycle efficiency η i in per unit.
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4. Compressor outlet temperature T 2e in Kand C.
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5. Turbine outlet temperature T 4e in Kand C due to expansion efficiency η t .
6. Practical cycle efficiency η p per unit, with η c and η t included.
7. Find the pressure ratio r p max that 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 drops P 1 ,
P 23 and P 4 .
Find the following:-
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8. Compressor outlet temperature T 2ea in Kand C, due to compression efficiency η c and the inlet
pressure drop P 1 .
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9. Turbine outlet temperature T 4ea in Kand C, due to expansion efficiency η t , the combustion
pressure drop P 23 , and the outlet pressure drop P 4 .
10. The work done on the mass flow to produce the desired output power of 12 MW.
11. Theoretical thermal efficiency η pa per unit, with all the losses included.
12. Overall thermal efficiency η pao with all losses included.

F.4 BASIC SOLUTIONS
Step 1. From (2.14),

δ = (1.0 − 1.4)/1.4 =−0.2857
δ
(P 2 /P 1 ) = 11.0 −0.2857 = 0.50403
Therefore,
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T 2 = T 1 /0.50403 = (273.0 + 20.0)/0.50403 = 581.31 K or 308.31 C.
Step 2. From (2.15),
δ
(P 3 /P 4 ) = 11.0 −0.2857 = 0.50403
Therefore,
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T 4 = T 3 × 0.50403 = (273.0 + 950.0) × 0.50403 = 616.43 K or 343.43 C.
Step 3.
δ
r = 11.0 −0.2857 = 0.50403
p
and
β
r = 11.0 +0.2857 = 1.984
p