ME 09 406/PTME 09 4O5_THERMODYNAMICS (2009 admissions) Maximum: 70 Marks
Time : Three l{ours
Part A Answer all thc questions. Each qucstion carries 2 marks. I
1. State First law ofthermodynamics. 2, State Carnot's theorem. 3. State the Avogadro's law and state its significance. 4. Draw the generalizbd compressibility chart' 5. Define dew point temPerature. I
(5x 2=
10 marks)
Part B anY four .questions. lnEwer questiin rorriis 5 marhs.
Each
1.
State the Zeroth law'of thermotlynamics. Explain how
it
forms the basis for temperaturb
measurement.
2. Explain the signifisance of entropy' 3. Show how a reversible heat engine operates as a reversible refrigerator. 4. Define Available energ'y, Availability and lrreversibility.
p. E:rplain Third law of thermodynamics. 6. Deduce Clapeyron equation. o
1.
(4x 5 = 20 marks) Part
C
A closed system undergoes a thermodynamic cycle consisting of four separate and d.istinct The heat and work transferred in each process are as tabulated below : Process
t-2 2:3 3-4 +-L
Heat transfer in kJ/min. 20,000
-
Worh transfer in
kJ/min. 0
30,000
10,000
20,ooo
0
15,000
pro""rrLr.
-
25,000
Turn over
2
ct5641
Show that the data is consistent with the first law of thermodynamics. Also evaluate the network output in kW and the change in internal energy.
are relatedasfollows u=196+0.1?8 tand'pu=0-281 (t+279), oC, p is pressure (kN/m.2) and u specific voluine. where u is specifrc internal energ'y &J&g.), I is in
Z. Thepropertiesof acertainfluid. For this fluid find cu and
co'
Prove that irreversibility is created (entropy generated) whenever heat t;ransfer with frnite temp erature difference occurs4. Define Helmholtz function and Gibbs function and hence d.educe the two Maxwells relations. 5. What is the triple point ? Find the specific volume, enthalpy and internal energy ofwet steam at 18 bar dryness fraction 0.9. the mass of 6. A mixture of hydrogen and oxygen is in the ratio of 2 to L bV lofume determineand ' hydrogen required aird volom" ofttt" container per kg.. of oxygen if.tlie temperature pressure oith" -i*t tre are to be 100 kPa and 300 kPa respectively ; humidity of 60 %- The total pressure 7 . A moist air has a dry bulb temperature of 300' C. and relative point is 100 kpa. Determine the partial pressure of the water vapour, humiclity ratio and the dew temperature. g. Dry bulb and wet bulb temperature of moist air are found to 30o C. and 2loC. respectively. From the psychometric chart obtain :
B.
(a) Relative humiditY. (c) Specifie enthalPY. (e) Specific volume of the mrxttire.-
(b) ".
-
.(ul
Humidity ratio. temPerature'
,.,l:*.rl."t
(4 x'10 = 40 marks)
g'q*h:.y....
A closed system undergoes a thermodynamic cycle consisting of four separate and ... Show that the data is consistent with the first law of thermodynamics.
