THERMODYNAMICS QUESTION PAPER
Que – 1(a): DEFINE THE
FOLLOWING
QUASI-STATIC PROCESS,
THERMODYNAMIC EQUILIBRIUM, HEAT & WORK, INTENSIVE AND EXTENSIVE PROPERTY
Que – 1(b): IN A PISTON
CYLINDER ARRANGEMENT, THE NON FLOW REVERSIBLE PROCESS IS GIVEN BY V = 200/PM3,
WHERE P IS IN BAR, FIND THE WORK DONE WHEN THE PRESSURE INCREASES FROM 1 BAR TO
10 BAR. INDICATE THAT THE PROCESS IF COMPRESSION OR EXPANSION.
QUE – 2(a): PROVE THAT
THE MOLE FRACTION OF EACH CONSTITUENTS IN A MIXTURE OF PERFECT GASES IS THE
SAME AS ITS VOLUME FRACTION AND ALSO, THE RATIO OF ITS PARTIAL PRESSURE TO THE
TOTAL PRESSURE.
QUE –
2(b): A MIXTURE OF GASES HAVING 2 KG HE AND 5 KG N2 AT 300
C AND 1 BAR IS COMPRESSED IN A REVERSIBLE ADIABATIC PROCESS TO 6 BAR. FIND:
i.
FINAL PRESSURE OF THE CONSTITUENTS
ii.
THE FINAL TEMPERATURE
iii.
CHANGE IN INTERNAL ENERGY OF THE MIXTURE DURING PROCESS
TAKE (CS)N2
= 0.744 , (CV)HE = 3.157
(CP)N2 =
1.049 , (CP) HE =
5.296KJ/KG0K
QUE – 3: THE MASS
FLOW RATE OF AIR THROUGH A RECIPROCATING COMPRESSOR IS 0.4 KG/SEC.THE AIR
ENTERS AT 6 M/SEC. WITH A PRESSURE OF 1 BAR AND SPECIFIC VOLUME OF 0.85 M3
KG AND LEAVES AT 4.5 M/SEC WITH A PRESSURE OF 6.9 BAR AND SPECIFIC VOLUME OF
0.16 M3/KG. THE EXTERNAL ENERGY OF THE AIR LEAVING THE COMPRESSOR IS
88 KJ/KG GREATER THAN THAT OF AIR ENTERING COOLING WATER OF THE CYLINDER JACKET
ABSORBS HEAT AT A RATE OF 59 KW. DETERMINE THE POWER REQUIRED TO DRIVE THE
COMPRESSOR AND INLET AND OUTLET PIPE-CROSS-SECTION AREAS.
QUE – 4(a): WHAT ARE
THE LIMITATION OF FIRST LAW OF THERMODYNAMICS? STATE THE SECOND LAW AS STATED
BY KELVIN – PLANK AND CLAUSIUS ALSO PROVE THEIR EQUIVALENCE?
QUE – 4(b): AN ENGINEER
CLAIMS HIS ENGINE TO DEVELOP 3.675 KW ON TESTING THE ENGINE CONSUMES 0.44 KG OF
FUEL PER HR HAVING A CALORIFIC VALUE OF 41800 KJ/KG. THE MAXIMUM TEMPERATURE
RECORDED IN THE CYCLE IS 14000C AND MAXIMUM IS 3500C.
FIND WHETHER THE ENGINE IS JUSTIFY IN HIS CLAIM. IF HOWEVER THE MAXIMUM &
MINIMUM TEMP. ARE MAINTAINS AT 2000C AND 2500C, WILL THE
PERFORMANCE BE POSSIBLE AN THE SAME ENGINE
QUE – 5(a): STATE AND
PROVE THE CLAUSIUS INEQUALITY
§dQ/T < 0
, FOR IRREVERSIBLE PROCESS
§ Dq/T = 0 ,
FOR A REVERSIBLE PROCESS
QUE – 5(b): 2 KG OF
WATER AT 940C IS MIXED WITH 3 KG OF WATER AT 100C IN AN
ISOLATED SYSTEM. CALCULATE THE CHAGE IN ENTROPY DUE TO MIXING PROCESS?
QUE – 6(a): DERIVE AN
EXPRESSION FOR AVAILABILITY OF A STEADY FLOW SYSTEM?
QUE – 6(b): CALCULATE
THE UNAVAILABLE EVERY IN 60 KG OF WATER AT 600C WITH RESPECT TO THE
SURROUNDINGS AT 60C, THE PRESSURE OF WATER BEING I ATMOSPERE.
QUE – 7(a): EXPLAIN THE
WORKING OF A THROTTLING AND SEPERATING CALORIMETER FOR THE MEASUREMENT OF DRYNESS
FRACTION OF STEAM. WITH THE HELP OF NEAT SKETCH.
QUE – 7(b): CALCULATE
THE INTERNAL ENERGY PER KG OF SUPERHEATED STEAM AT A PRESSURE OF 10 BAR AND A
TEMPERATURE OF 3000C. ALSO FIND THE CHANGE OF INTERNAL ENERGY IF
THIS STEAM IS EXPANDED TO 1.4 BAR AND DRYNESS FRACTION 0.8.
QUE – 8 : DERIVE THE
FOLLOWING RELATIONS:
(a) Tds = CV
dT + p T Dv/K
(b)TdS = CP Dt – VβTdP
(c) TdS = CVK/βV dV
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