Download AKTU (Dr. A.P.J. Abdul Kalam Technical University (AKTU), formerly Uttar Pradesh Technical University (UPTU) B-Tech 3rd Semester (Third Semester) 2018-2019 Thermodynamics Rme 302 Question Paper
no-mmn I I Hi I I W
B TECH
(SE M-III) THEORY EXAMINATION 2018-19
THBRMODYNAMICS
Time: 3 Hours Total Marks: 70
Note: Attempt ail Sections. If require any mesing data; then choose suitably.
SECTION A
l. Attempt all questions in brief. 2 x 7 - l4
Differentiate betwaen intensive ancl extensive properties
What do you mean by Joule-Tlompson coefficient and Inversion curve?
State Kelvin Planck and Claus'us statement of second law of themodynamics.
What is refrigeration and What are the required properties of a refrigerant?
What dd you mean by available and unavailable energy?
What is the difference between the critical point and the triple point?
Explain what you understand by themodynamietgegmlibrimn?
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states} ? h
2. Attempt any mm o! the following:
a) A heat pump is used to meet the hazing requirements 01 a house and mait?gin?tt at 20?C On a
day when the outdoor air temperaturedrops to 2?C the house Is estimate?wibse heat at a rate of
so 000 um If the heat pum Iiid'er these conditions has a COP of2?.? 8312mm ((1) the power
consumed by the heat pump anil(b) the me at which heat Is absorbed front
b) When a man returns to Iij??iwcll-sealed house on a. Summer day, he ?hds that the house Is at 32?C
He turns on the air con?itioner, which cools the entire house t9?39?b In 15 min [f the COP of the
air-conditioning system is 2 5. determine the power dmwii?y the air conditioner. Assume the
entire mass within the house Is equivalent to 800 kg of air f9: which cv= 0 72 kJ?kg ?C and c,
- l ..0kJ/kg?C
c) De?ne in pure substance by suitable phase change diagram the term (i) Triple Point (ii) Critical
Point (iii) Saturation states (iv) Sub cooled stategt??uperheated vapour state.
I!) An insulated rigid tank 13 di?v ided intotwo eqn?iparts by a partition Initially, one part contains 4
kg of an ideal gas at 800 kPa and 50?C antithe other part is evacuated The partition is now
removed and the gas expands into the entire tank Determine the ?nal temperature and pressure in
the tank.
e) Write down the first and second IdS? Iquations and derive the expression for the difference In heat
capacities CI; and CI- .
SECTION C
3. Attempt any one part of the following: ' 7 x 1 - 7
(a) A piston-cylinder device initially contans 0.4 m3 of air at 100 kPa and 80?C.The air is
now compressed [0 0.1 m3 insuch a way that the Iemperahuc inside the cylinder remains
constant. Determine the workdone during this process.
(b) Alf at 100 Wit and 280 K is compressed steadily to 600 kPa and 400 K. The mass ?ow
rate of the air is 0.02 kg/s, and a heat ioss of 16 kJ/kg occurs during the process.
Assuming the changes in kinetic and potential energies are negligible, determine the
necessary power input to the compressor.
Attempt any one part 01? the Iollowhg: 7 x 1 = 7
(a) The Tw0 Carnot engines work in series between the sources and sink temperatures of 550 K
350 K. If both engines develop equal power, determine the intermediate temperature.
(b) Show that the Kelvin?Planck and the Clausius statement of the second law of
themmdynamics are equivalent
Attempt any one part of the following: 7 x 1 = 7
(a) In a certain process, a vapour while condensing at 420?C, transfers heat to water
evaporating at 250?C. The resulting steam is used in power cycle, which rejects heat at
35"C. What is the fraction of the available energy in the heat transferred from the process
vapour at 420?C that is lost due to the irreversible heat transfer at 2500C?
(b) State the Clapeyron equation and discuss its importance during phase change of pure
substance Derive the equation for Clansius~Clapeyron equation for evaporation of
liquids. .,
Attempt any one part of the following: 1.} .i ' 7 x l r- 7,1?;
5..?
(3) Steam at 20 bar and 360?C IS expandgdkn a steam turbine to 0. 08 bar. It the??uners a
condenser, where it is condensed {gamma liquid water The pump feeds bge?he water
into the boiler (:1) Assuming 1 roccsses ?nd per Kg of steam the net work and the
cvcle ef?ciency. (b) If the mil: and the pump have each 80 ?/n ef?ciency, ?nd the
percentage reduction in the? net Work and cycle ef?ciency
(b) Explain the following pwcesses and show them on psychometric (?g;
i. Sensible hcatmymd cooling 9,3. -
ii. Heating amiIgu?iidi?cation ..
iii. Cooling and dehumidi?eation
Attempt any one part of the following: 7 x l - 7
(a) Explain the vapour compression cycle with the?help'of T- s and p- -h diagram.
(b) A refrigemtor opera: as on ideal vapour gnmpiession cycle between 0 14 MP: and 0. 8
MP3. 1f the mass ?ow rate of the refrigerant is O 06 Kg/s, determme: (a) the rate of heat
removal from the refrigerated space- f(b) the pow er input to the compressor (c) the heat
rejection rate in the condenser anti Cd} the COP
This post was last modified on 29 January 2020