TITLE.PM5

GAS POWER CYCLES 699

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\M-therm\Th13-6.pm5

∴ T 2 ′ =

435 4 293

08

.

.

−

+ 293 = 471 K

Now mf × C = (ma + mf) × cp × (T 3 – T 2 ′)

[ma = mass of air, mf = mass of fuel]

∴ T 3 =

mC

cm m

f

p a f

×

()+

+ T 2 ′ =

1 41800

1.024 (90 1)

×

+ + 471 = 919.5 K

Also, T

T

p

p

4

3

4

3

1

=

F

HG

I

KJ

−γ

γ

or T 4 = T 3 ×

p

p

4

3

1

F

HG

I

KJ

−γ

γ

= 919.5 ×

1.

3.

01

9

14 1

F^14

HG

I

KJ

. −
.
= 625 K

Again, ηturbine =

TT

TT

34

34

−′

−

∴ 0.85 =

919 5

919 5 625

. 4
.

−′

−

T

∴ T 4 ′ = 919.5 – 0.85(919.5 – 625) = 669 K

ηthermal =

()()

()

TT T T

TT

34 2 1

32

−′− ′−

−′

=

−−−

−

(919.5 669) (471 293)=

(919.5 471)

72.5

448.5 = 0.1616 or 16.16%. (Ans.)

Heat Exchanger Cycle. Refer Figs. 13.66 (a) and (b)

T 2 ′ = 471 K (as for simple cycle)

T 3 = 919.5 K (as for simple cycle)

Work

2 ¢

C.C.

CT

Fuel

3

4 ¢

Exhaust

Heat

exchanger

1

Air in

(a)

5