Page 105 - DJJ20063- Thermodynamics 1

DJJ20063- Thermodynamics 1

From equation 3.14

 V  n
p = p 1  1 
2
 V 2 

 1  . 1 15
= 30 x  5 . 8 



= 2.56 bar

Now,

3
3
-6
V2 = 510 cm = 510 x 10 m
and,
V
2 = 8.5
V 1

Then,

510x 10 6 −
V 1 =
5 . 8

-6
3
= 60 x 10 m

Work output during polytropic expansion is given by equation 3.17 as:

p V − p V
W = 1 1 2 2 [larger pV- small pV]
n − 1

( 30x 10 5 )( 60x 10 6 − ) . 2 ( − 56x 10 5 ) ( − 510x 10 6 − )
=
. 1 15 − 1

= 330 J
= 0.33 kJ

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