1. thermodynamics, ic engine, rac_objective

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9Test 1 (Obj) : Thermo, I.C. Engine, RAC

ESE-2014 : Test SeriesMECHANICAL ENGINEERING

Test 1 (Obj) : THERMODYNAMICS, I.C. ENGINES, RAC

SlSlSlSlSl..... NNNNNooooo .: 060414.: 060414.: 060414.: 060414.: 060414

A N S W E R S

1.1.1.1.1. (b)

2.2.2.2.2. (a)

3.3.3.3.3. (a)

4.4.4.4.4. (a)

5.5.5.5.5. (a)

6.6.6.6.6. (c)

7.7.7.7.7. (d)

8.8.8.8.8. (d)

9.9.9.9.9. (b)

10.10.10.10.10. (b)

11.11.11.11.11. (d)

12.12.12.12.12. (d)

13.13.13.13.13. (b)

14.14.14.14.14. (b)

15.15.15.15.15. (b)

16.16.16.16.16. (b)

17.17.17.17.17. (d)

18.18.18.18.18. (b)

19.19.19.19.19. (a)

20.20.20.20.20. (d)

21.21.21.21.21. (c)

22.22.22.22.22. (c)

23.23.23.23.23. (b)

24.24.24.24.24. (d)

25.25.25.25.25. (b)

26.26.26.26.26. (c)

27.27.27.27.27. (c)

28.28.28.28.28. (a)

29.29.29.29.29. (d)

30.30.30.30.30. (c)

31.31.31.31.31. (b)

32.32.32.32.32. (b)

33.33.33.33.33. (d)

34.34.34.34.34. (a)

35.35.35.35.35. (a)

36.36.36.36.36. (c)

37.37.37.37.37. (d)

38.38.38.38.38. (c)

39.39.39.39.39. (b)

40.40.40.40.40. (c)

41.41.41.41.41. (a)

42.42.42.42.42. (a)

43.43.43.43.43. (b)

44.44.44.44.44. (d)

45.45.45.45.45. (b)

46.46.46.46.46. (a)

47.47.47.47.47. (a)

48.48.48.48.48. (b)

49.49.49.49.49. (d)

50.50.50.50.50. (c)

51.51.51.51.51. (d)

52.52.52.52.52. (b)

53.53.53.53.53. (a)

54.54.54.54.54. (c)

55.55.55.55.55. (d)

56.56.56.56.56. (a)

57.57.57.57.57. (c)

58.58.58.58.58. (a)

59.59.59.59.59. (d)

60.60.60.60.60. (c)



10 ESE-2014 : TEST SERIES MECHANICAL ENGINEERING

1.1.1.1.1. (b)(b)(b)(b)(b)

m, v, T, P, m2

v2

,

T, P,

m2

v2

,

T, P,

m V,

2 2 Extensive properties

T, P, Intensive properties

4.4.4.4.4. (a)(a)(a)(a)(a)

v

P

n = 0

n = 1

n = 2

n =

5.5.5.5.5. (a)(a)(a)(a)(a)As per Gibbs phase rule,

F = C P + 2= 1 3 + 2 = 0

6.6.6.6.6. (c)(c)(c)(c)(c)

W1 = 51 1 1 10

2= 0.5 102 kJ (ve)

W2 = 51 1 1 10

2= 0.5 102 kJ (+ve)

Net work done = W1 W2 = 0

9.9.9.9.9. (b)(b)(b)(b)(b)

P

T C( ) 273.15

Gas1

Gas2

Gas3

EXPLANATIONS

10.10.10.10.10. (b)(b)(b)(b)(b)Q = W + U

U for the cycle = 0

Q = ( ) ( )W . .= 1 600 300 0 3 0 12

= 0.1 300 = 30 kJ

11.11.11.11.11. (d)(d)(d)(d)(d)

Initial volume, V = RTP

R = Cp Cv = 0.3 kJ/kgK,P = 300 kPa, T = 300 K

V =.

.

=

33

3

0 3 10 3000 3m

300 10Work done = 20 15 60

= 18000 J = Heat additionmCv (T2 T1) = 18000

T2 = 325.7 KFor constant volume process,

PT

1

1=

PT

2

2

P2 =T PT

21

1

=.

.

=

325 7 300325 7kPa

300P2 = 325.7 kPa

12.12.12.12.12. (d)(d)(d)(d)(d)

Q Q

T1 T2

S1 =Q WT K

= =

1

1500 5300




S 2 =QT T

=

2 2

1500

S1 + S2 = 0.25

or .T

=

2

15005 0 25

or 5.25 =T2

1500

T2 = ..=

1500285 7K

5 25

T2 = 285.7 273 = 12.7C

13.13.13.13.13. (b)(b)(b)(b)(b)Irreversibility,

I = T0 S

=

+ = 3200 3200

300 2400 kW1200 300

Availability,A = 3200 2400 = 800 kW

14.14.14.14.14. (b)(b)(b)(b)(b)Helmholtz function,

F = U TSGibbs function,

G = H TSG F = U H

For ideal gas,U f1(T), H f2 (T)

Difference between G and F depends on

temperature only.

15.15.15.15.15. (b)(b)(b)(b)(b)Work and heat interactions are the forms ofenergy in transit, observed at theboundaries of a system. They are notproperties of a system. They are pathfunctions, their magnitudes dependingupon the path the system follows during achange of state. Energy in storage calledinternal energy is a point or state functionand hence a property of the system.

16.16.16.16.16. (b)(b)(b)(b)(b)

a

v 2 force of cohesion

b Co-volume

19.19.19.19.19. (a)(a)(a)(a)(a)

( )ap v b RTv

+ = 2

pv3 (pb + RT) v2 + av ab = 0

( )cc

T T cc

p RT av vv b=

= + =

2 3

20

( )cc

ccT T

p RT a

v vv b=

= =

2

2 3 4

2 60

From these equation, we get

a = cc cv

p v , b =233

22.22.22.22.22. (c)(c)(c)(c)(c)

Over square ratio = d

.L

= 1 1

Vs =dd L.

= =

32 245

4 4 1 1

d 3 = 343 or d = 7 cm

L =d

..

= 6 36 cm1 1

23.23.23.23.23. (b)(b)(b)(b)(b)Total volume/cylinder,

Vtotal = Vc + Vs = =2000

500 cc4

Compression ratio,

r = c s sc

V VV

V+

= 500 or = 450 cc

Volume of air taken in/cycle= v Vs = 0.7 450 = 315 cc



12 ESE-2014 : TEST SERIES MECHANICAL ENGINEERING

a

f

mm

= 9

mf = =315

35cc9

Energy supplied/ cylinder= 35 106 34 103 = 1.19 kJ

25.25.25.25.25. (b)(b)(b)(b)(b)

v

0.55

Inlet valve mach index (z)

26.26.26.26.26. (c)(c)(c)(c)(c)

otto =r

1

11

diesel = ( )c

c

rrr

1factor

1 11

1

29.29.29.29.29. (d)(d)(d)(d)(d)

P

V

2 3

4

1

r =VV

=1

220

Vs = V1 V2 = 19V2V3 = 0.05 Vs + V2V3 = (19 0.05 + 1)V2

VV

3

2= rc = 1 + 0.95 = 1.95

30.30.30.30.30. (c)(c)(c)(c)(c)Heat rejection for Otto engine would be moreand hence its efficiency would be least.

32.32.32.32.32. (b)(b)(b)(b)(b)For CI engines, the normal paraffins are thebest fuels and aromatics are the leastdesirable.

41.41.41.41.41. (a)(a)(a)(a)(a)Catalytic converters are called three wayconverters because it reduces theconcentration of CO, HC and NOx in theexhaust (three concentrations).

42.42.42.42.42. (a)(a)(a)(a)(a)

COP =T

T T= =

1

2 1

2002

100

COP = AqW

W =1

kW = 0.5kW2

43.43.43.43.43. (b)(b)(b)(b)(b)For Cm Hn Clq Fpn + p + q = 2m + 2,formula is R (m 1) (n + 1) p

P = 2, No hydrogen atom, n = 0 q = 2 1 + 2 = 4 Designation for R - 12 is CCl2 F2

48.48.48.48.48. (b)(b)(b)(b)(b)When the refrigerant in the gas cylinderor in the system is allowed to remainstanding for a period and come toequilibrium with the ambient temperature,the pressure recorded is named as thestanding pressurestanding pressurestanding pressurestanding pressurestanding pressure.

49.49.49.49.49. (d)(d)(d)(d)(d)

COP =h hh h

1 4

2 1

=. . .

.. . .

= =

350 3 173 7 176 63 97

394 7 350 3 44 4




51.51.51.51.51. (d)(d)(d)(d)(d)

w

s

PP

= 0.7

Pw = 2.975 kPaPw + Pa = P

Pa = 100 2.975 = 97.025 kPa

52.52.52.52.52. (b)(b)(b)(b)(b)

t1 t2

22

1

1

2 <

2 1t t >

1

DBT

55.55.55.55.55. (d)(d)(d)(d)(d)

te = t h

+0I

57.57.57.57.57. (c)(c)(c)(c)(c)

BPF = .

= = =

25 20 5 10 25

40 20 20 4

coil = 1 BPF = 0.75

60.60.60.60.60. (c)(c)(c)(c)(c)R 11 CCl2 FR 12 CCl2 F2R 13 CCl F3R 22 CHCl F2

Class one Ozone depleting substances areR 11, R 12, R 113, R115.

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1. thermodynamics, ic engine, rac_objective

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