COURSE FILE
Course File
For
THEMODYNAMICS
For B.Tech II Year - I Semester2015 - 16
CVR Emblem
CVR College of Engineering(Autonomous)Vastunagar, Mangalpalli
(V), Ibrahimpatan (M),R. R. Dist. Pin : 501 510, E-mail :
[email protected] : http://cvr.ac.in
THERMODYNAMICS
syllabus
UNIT I
Introduction: Basic Concepts : System, Control Volume,
Surrounding, Boundaries, Universe, Types of Systems, Macroscopic
and Microscopic viewpoints, Concept of Continuum, Thermodynamic
Equilibrium ,State, Property, Process, Cycle Reversibility Quasi
static Process, Irreversible Process, Causes of Irreversibility
Energy in State and in Transition, Types, Work and Heat, Point and
Path function.
UNIT II
Zeroth Law of Thermodynamics Concept of quality of Temperature
Principles of Thermometry Reference Points Const. Volume gas
Thermometer Scales of Temperature, Ideal Gas Scale PMMI - Joules
Experiments First law of Thermodynamics Corollaries First law
applied to a Process applied to a flow system Steady Flow Energy
Equation.
UNIT III
Limitations of the First Law Thermal Reservoir, Heat Engine,
Heat pump, Parameters of performance, Second Law of Thermodynamics,
Kelvin-Planck and Clausius Statements and their Equivalence /
Corollaries, PMM of Second kind, Carnots principle, Carnot cycle
and its specialties, Thermodynamic scale of Temperature
UNIT IV
Clausius Theorem, Entropy, Principle of Entropy Increase Energy
Equation, Availability and Irreversibility Thermodynamic
Potentials, Gibbs and Helmholtz Functions, Maxwell Relations
Elementary Treatment of the Third Law of Thermodynamics.
UNIT V
Pure Substances, p-V-T- surfaces, T-S and h-s diagrams, Mollier
Charts, Phase Transformations Triple point at critical state
properties during change of phase, Dryness Fraction Clausius
Clapeyron Equation, Property tables. Mollier charts Various
Thermodynamic processes and energy Transfer Steam Calorimetry.
UNIT VI
Perfect Gas Laws Equation of State, specific and Universal Gas
constants various Non-flow processes, properties, end states, Heat
and Work Transfer, changes in Internal Energy Throttling and Free
Expansion Processes Flow processes Deviations from perfect Gas
Model Vander Waals Equation of State Compressibility charts
variable specific Heats Gas Tables.
UNIT VII
Mixtures of perfect Gases Mole Fraction, Mass friction
Gravimetric and volumetric Analysis Daltons Law of partial
pressure, Avogadros Laws of additive volumes Mole fraction , Volume
fraction and partial pressure, Equivalent Gas const. And Molecular
Internal Energy, Enthalpy, sp. Heats and Entropy of Mixture of
perfect Gases and Vapour, Atmospheric air - Psychometric Properties
Dry bulb Temperature, Wet Bulb Temperature, Dew point Temperature,
Thermodynamic Wet Bulb Temperature, Specific Humidity, Relative
Humidity, saturated Air, Vapour pressure, Degree of saturation
Adiabatic Saturation, Carriers Equation Psychometric chart.
UNIT VIII
Power Cycles : Otto, Diesel, Dual Combustion cycles, Sterling
Cycle, Atkinson Cycle, Ericcson Cycle, Lenoir Cycle Description and
representation on PV and T-S diagram, Thermal Efficiency, Mean
Effective Pressures on Air standard basis comparison of Cycles.
Refrigeration Cycles: Brayton and Rankine cycles Performance
Evaluation combined cycles, Bell-Coleman cycle, Vapour compression
cycle-performance Evaluation.
TEXT BOOKS:
Engineering Thermodynamics / PK Nag /TMH, III Edition
Thermodynamics An Engineering Approach Yunus Cengel & Boles/
TMH
Fundamentals of Engineering Thermodynamics R.Yadav/Central
Publishing house
REFERENCES:
Thermodynamics J.P. Holman / McGraw Hill
An introduction to Thermodynamics / YVC Rao / New Age
Engineering Thermodynamics K. Ramakrishna / Anuradha
Publishers.
Lecture SCHEDULE
Sl. noTopicNo. of Regular Class
UNIT I
1.System, Control Volume, Surrounding, Boundaries, Universe,
Types of Systems02
2.Macroscopic and Microscopic viewpoints, Concept of Continuum,
Thermodynamic Equilibrium01
3.State, Property, Process, Cycle Reversibility Quasi static
Process,02
4.Irreversible Process, Causes of Irreversibility Energy in
State and in Transition, Types02
5.Work and Heat, Point and Path function.01
Sub Total08
UNIT II
1.Zeroth Law of Thermodynamics Concept of quality of
Temperature01
2.Principles of Thermometry Reference Points01
3Const. Volume gas Thermometer Scales of Temperature, Ideal Gas
Scale02
4PMMI - Joules Experiments First law of Thermodynamics
Corollaries 02
5First law applied to a Process applied to a flow system 02
6Steady Flow Energy Equation.01
Sub - Total09
UNIT III
1.Limitations of the First Law Thermal Reservoir, Heat Engine,
Heat pump, Parameters of performance02
2.Second Law of Thermodynamics, Kelvin-Planck and Clausius
Statements and their Equivalence / Corollaries 02
3PMM of Second kind, Carnots principle01
4Carnot cycle and its specialties, Thermodynamic scale of
Temperature02
Sub - Total07
UNIT IV
1Clausius Theorem, Entropy, Principle of Entropy Increase01
2Energy Equation, Availability and Irreversibility01
3Thermodynamic Potentials, Gibbs and Helmhlotz functions,
Maxwell Relations02
4Elementary treatment of the Third law of Thermodynamics01
Sub Total05
UNIT V
1.Pure Substances, p-V-T- surfaces, T-S and h-s diagrams,02
2.Mollier Charts, Phase Transformations01
3Triple point at critical state properties during change of
phase01
4Dryness Fraction Clausius Clapeyron Equation, Property
tables.02
5Mollier charts Various Thermodynamic processes and energy
Transfer02
6Steam Calorimetry01
Sub Total09
UNIT VI
1.Perfect Gas Laws Equation of State, specific and Universal Gas
constants01
2various Non-flow processes, properties, end states, Heat and
Work Transfer02
3changes in Internal Energy Throttling and Free Expansion
Processes02
4Flow processes Deviations from perfect Gas Model Vander Waals
Equation of State02
5Compressibility charts variable specific Heats Gas
Tables.02
Sub Total09
UNIT VII
1.Mixtures of perfect Gases Mole Fraction, Mass friction
Gravimetric and volumetric Analysis Daltons Law of partial
pressure02
2.Avogadros Laws of additive volumes Mole fraction ,Volume
fraction and partial pressure, Equivalent Gas constant and
Molecular Internal Energy02
3.Enthalpy, sp. Heats and Entropy of Mixture of perfect Gases
and Vapour, , Atmospheric air02
4.Psychometric Properties Dry bulb Temperature, Wet Bulb
Temperature, Dew point Temperature,01
5Thermodynamic Wet Bulb Temperature, Specific Humidity, Relative
Humidity, saturated Air, Vapour pressure02
6Degree of saturation Adiabatic Saturation, Carriers Equation
Psychometric chart. 01
Sub Total10
UNIT VIII
1.Otto, Diesel, Dual Combustion cycles, Sterling Cycle02
2Atkinson Cycle ,Ericcson Cycle, Lenoir Cycle 01
3Description and representation on PV and T-S diagram, thermal
efficiency01
4Mean Effective Pressures on Air standard basis comparison of
Cycles.
01
5Brayton and Rankine cycles Performance Evaluation01
6Bell-Coleman cycle, Vapour compression cycle - performance
Evaluation02
Sub Total08
GRAND TOTAL65
QUESTIONSUNIT I
Define the term property. State the differences between
extensive, intensive and specific properties of a thermodynamic
system. Give few examples for each.
A mass of 2.5 kg of air is compressed in a quasi static process
from 0.1 MPa to 0.7 MPa for which PV = constant. The initial
specific volume is 0.80 m3/kg. Find the work done by the piston to
compress the air.
Define thermodynamic work. Show that work is a path
function.
Compare the work and heat transfers.
How do the terms energy content and energy transfer differ from
each other?
What is the concept of continuum? How will you define density
and pressure using this concept?
A gas system, comprised by a piston and cylinder, undergoes a
change of state such that the product of pressure and volume
remains constant. If the process begins at a pressure 300 KPa and a
volume 0.015 m3 and proceeds until the pressure falls to half its
initial value, determine the magnitude and direction of work
transfer.
A rigid and insulated tank is divided into two compartments. One
compartment of volume 1 m3 contains (Cp =29. 1 j /mol k; Cv=20.786
j /mol k) at 300 K and 1 bar while second compartment of volume 2
m3 contains helium (Cp=20.786 j/mol j ; Cv=12.4717 j/mol k) at 100
k and 5 bar. The gases are allowed to mix by removing the
partition. determine
(a) Molar composition of mixture (b) Final temperature and
pressure of the mixture (c) Change in entropy of helium and air (d)
Net entropy change.
UNIT II
A reciprocating air compressor takes in 2 m3/min at 0.11 MPa,
200C which it delivers at 1.5 MPa, 1110C to an after cooler where
the air is cooled at constant pressure to 250C. The power required
by the compressor is 4.15 KW. Determine the heat transfer inThe
compressor, and
The cooler.
Take Cp=1.005 KJ/Kg-K and R = 0.287 KJ/Kg-K.
Write the unit of temperature and explain the International
fixed points.
Explain in detail the ideal gas temperature scale.
A cylinder closed at both ends is divided into two compartments
by a frictionless and freely moveable piston; both the piston and
cylinder are perfectly insulated regarding heat interactions. One
compartment contains air and other contains nitrogen. Initially
both air and nitrogen are at 1.0 bar pressure 298 K temperature and
0.02 m3 volume. An electric heater on the side of air compartment
heats the air till the volume of nitrogen is reduced to 0.01 m3.
Evaluate the final temperature of air and heat supplied to it. Take
for air Cv = 715 J/kg-k, R = 287 J/kg-k and for nitrogen = 1.4.
State the zeroth law of thermodynamics. Explain how it forms the
basis for temperature measurement?
A closed system undergoes a thermodynamic cycle consisting of
four separate and distinct processes. The heat and work transferred
in each process are as tabulated below.
ProcessHeat Transfer in KJ/min WorkWork Transfer in KJ/min
Work
1-220,0000
2-3-10,00030,000
3-4020,000
4-115000-25,000
Show that the data is consistent with the first law of
thermodynamics. Also evaluate the net work output in KW and the
change in internal energy.
A gas undergoes a thermodynamic cycle consisting of three
processes beginning at an initial state where P1=1 bar, V1 = 1.5m3
and U1 = 512 kJ. The processes are as follows:
Process 1-2: Compression with PV=constant to P2 = 2 bar, U2 =
690 KJ
Process 2-3: W23 =0, Q23=- 150 KJ, and
Process 3-1: W31 = 50 KJ.
Neglecting KE and PE changes, determine the heat interaction Q12
and Q31.
Using an example how do you apply the First law to a
Process?
Define PMMI.
UNIT III
A heat engine is supplied heat at the rate of 1700 kJ/ min and
gives an output of 9 kW. Determine the thermal efficiency and the
rate of heat rejection.
An ordinary house hold refrigerator receives electrical work
from its surroundings and discharges energy by heat transfer to the
surroundings. Is this in violation of the Kelvin Planck statement
of the second law of thermodynamics? Explain. Consider the same
question for an electric motor at steady state.
Explain diagrammatically the perpetual motion machine of the
second kind. How does it violate the Second law of thermodynamics
?
Two reversible heat engines A and B are arranged in series.
Engine A rejects heat directly to engine B. A receives 200 KJ at a
temperature of 4210C from the hot source while engine B is in
communication with a cold sink at a temperature of 50C.
If the work output of A is twice that of B find
Intermediate temperature between A and B and
Efficiency of each engine.
Two containers p and q with rigid walls contain two different
monatomic gases with masses mp and mq gas constants Rp and Rq, and
initial temperatures Tp and Tq respectively, are brought in contact
with each other and allowed to exchange energy until equilibrium is
achieved. Determine:
The thermal temperature of the two gases and
The change of entropy due to this energy exchange.
State the limitations of first law of thermodynamics.
What is a thermal energy reservoir?
An engine operating on a Carnot cycle works with in temperature
limits of 600 K and 300 K. If the engine receives 2000 KJ of heat,
evaluate the work done and thermal efficiency of the engine.
UNIT IV
Derive an expression for availability in non flow process.
In throttle control governing of steam turbine, the supply steam
at 6 Mpa (60 bar) and 650 C throttles to 4 Mpa (40 bar) in the
governor. Determine the reversible work and the irreversibility of
this process.
5 kg of oxygen is heated in a reversible non flow constant
volume process from temperature of 60 C until the pressure is
doubled. Determine
Final temperature(ii)work done
(iii)change in internal energy(iv)heat transferred
(v)change in enthalpy and (vi)change in entropy
Assume Cv = 0.653 kJ/ kg K, Cp = 0.913 kJ/ kg K
Air is compressed in a reversible isothermal steady flow process
from 1 bar and 40 C to 10 bar. Determine the work done on the gas
per kg and the heat transferred. Also determine the change of
entropy per kg of the mass flow. Assume R = 0.287 kJ/ kg K
A cylinder fitted with piston contains 1 kg of air at 140 kPa,
50 C. Work is done by the piston on the gas. The final pressure is
550 kPa and the final temperature is 93 C. Determine the reversible
work per kg of air for this process.
A closed system contains 0.5 kg of air. It expands from 2bar,
600C to 1 bar, 4O 0C. During expansion it receives 2 kJ of heat
from a reservoir at 1002 C. Assuming atm, aspheric conditions to be
at 0.95 bar and 300 C, calcu1ate
(i) The maximum work, (ii) Work done an atmosphere, and(iii)
Change in availability
An adiabatic cylinder of volume 10 m3 is divided into two
compartments A and B each of volume 3m3 and 4 m3 respectively, by a
thin sliding partition. Initially the compartment A is filled with
air at 6 bar and 600 K, whilst there is a vacuum in the compartment
A expands and fills both the compartments. Calculate the loss in
available energy. Assume atmosphere is at 1 bar and 300 K.
A steam turbine receives 8000 kg of steam per hour at 3 Mpa and
320 C and exhausts steam at 0.014 Mpa. The efficiency of the
turbine is 78%. Determine the power output of the turbine and
irreversibility per kg of steam for the actual change of state.
UNIT V
Explain Mollier diagram (h-s diagram)?
Explain the difference between internal energy and enthalpy of
wet steam and dry steam.
Find the specific volume, enthalpy and internal energy of wet
steam at 18 bar dryness fraction 0.8
Show that the adiabatic mixing of two fluids is
irreversible.
Show that if two bodies of thermal capacities C1and C2 at
temperatures T1and T2 are brought to the same temperature, T by
means of a reversible heat engine, then in
T=(C1 ln T1+C2 ln T2)/C1+C2
One kilogram of dry saturated steam is at 0.8 Mpa.
Find the temperature, specific volume, enthalpy, entropy and
internal energy ;
What are the changes of these properties from saturated liquid
to dry saturated vapour at the given pressure?
Describe the process of formation of steam and give its
graphical representation?
Steam enters an engine at a pressure 10 bar absolute and 2500C.
It is exhausted at 0.2 bar. The steam at exhaust is 0.9 dry.
Find
Drop in enthalpy
Change in enthalpy.
Explain the following terms relating to steam formation
Sensible heat of water
Latent heat of steam
Find the internal energy of 1 kg of steam at 20 bar when
It is super heated, its temperature being 4000C
It is wet, its dryness being 0.9.
Assume super heated steam to behave as a perfect gas from the
commencement of superheating and thus obeys Charles low. Specific
heat for steam = 2.3 k j /kg. ok.
UNIT VI
What is compressibility factor? Sketch and discuss the salient
features of the generalized compressibility chart.
1 kg of air is initially at temperature of 100 C. If goes
through the following processes to complete a cycle.
Reversible adiabatic compression until the pressure is increased
to 2.5 times
Reversible heat addition at constant pressure. The addition of
heat is to control that initial volume is reached.
Constant volume process which returns the system to initial.
Represent P=V and T-S plots and calculate foe each process the work
done and heat exchange. What would be the efficiency of the
cycle?
What are the advantages and disadvantages of air refrigeration
systems over the other?
Determine the temperature ratio (T2 / T1) (where T2 = source
temperature and T1 = sink temperature) for a Carnot refrigerator
whose COP is 5. Also calculate the refrigeration capacity of the
machine in tons of refrigeration if the power consumption is 8 kW.
If the cycle is used as heat pump, and the COP for heating cycle
and the quantity of heat pumped
1 kg of air at 1.2 bar pressure and 180C is compressed
isentropically to 7 bars. Find the final temperature and the work
done. If the air is cooled at the upper pressure to the original
temperature of 180C, what amount of heat is rejected and what
further work of compression is done?
(a) What is compressibility factor? Explain the basic
construction of generalized compressibility char.
(b) Determine the pressure of air at 1900C having a specific
volume of 0.00295 m3/kg by means of
Deduce the relationship between absolute temperature and
absolute pressure in an adiabatic process.
1.5 kg of air at pressure 6 bar occupies a volume of 0.2m3.If
this air is expanded to a volume of 1.1m3. Find the work done and
heat absorbed or rejected by the air for each of the following
methods of trying one the process.
isothermally
Adiabatic ally
UNIT VII
Write short notes on
Mole fraction
Volumetric analysis
Dry bulb temperature
An air water vapour mixture has a relative humidity of 60 % at l
atmosphere and 300C. Determine per 100m3 of the mixture
Mass of water Vapour
Mass of dry air
A certain mass of sulphur dioxide (S02) is contained in a vessel
of 0.145 m3 capacity, at a pressure and temperature of 24.2 bar and
20oC respectively. A valve is opened momentarily and the pressure
falls immediately to 7.8 bar. Sometime later the temperature is
again 20oC and the pressure is observed to be 10.2 bar. Estimate
the value of specific heat ratio.
A mixture of ideal gases consists of 3 kg of Nitrogen and 5 kg
of carbon dioxide at a pressure of 4 bar and temperature of 250C
.Find
Mole fraction of each constituent
Equivalent molecular weight of the mixture
Equivalent gas constant of the mixture
Partial pressure and partial volumes
Volume and density of the mixture
Cp & Cv of the mixture.
(a) Explain the diference between internal energy and enthalpy
of wet and dry steam
(b) 2 kg of steam initially at a pressure of 12 bar and a
temperature of 2500C expends polytropically to 1.2 bar. Find
Final condition
Work done
Change in entropy ,assume the index of expansion as 1.25
(a) Explain: "Available energy" and "Availability" and
"Irreversibility".
(b) A vessel of 0.4m3 capacity contains 0.42 kg of carbon
monoxide (molecular weight = 28) and 1 kg of air at 250C calculate
The partial pressure of each constituent
The total pressure in the vessel
Two reversible heat engines operate on Carnot cycle. They work
in series between a maximum and minimum temperature of 7500C and
300C. If the engines have equal thermal efficiencies and the first
rejects 456 kJ to the second, calculate:
The temperature at which heat is supplied to the second
engine
The heat taken from the source: and the work done by each
engine.
The barometer for atmospheric air reads 750 mm Hg ; the dry bulb
temperature is 33 C ; wet bulb temperature is 23 C. Determine
The relative humidity(ii)The humidity ratio
The dew point temperature(iv)Density of atmospheric air
Calculate all the Psychrometric properties of air when dry bulb
temperature is 21 C and relative humidity is 30 %, at barometric
pressure of 7670 mm of Hg.
UNIT VIII
Sketch the p-V and T-s diagrams of diesel cycle.
Calculate the percentage loss in the ideal efficiency of a
diesel engine with Compression ratio 14 if the fuel cut-off is
delayed from 5% to 8%.
Explain the dual combustion cycle. Derive an expression for the
efficiency of dual cycle?
Which air-standard cycle is used in I.C. Engines? Explain the
differences between Otto cycle and Dual cycle.
What is principle of operation of an electrical calorimeter?
A vessel of 0.04 m3 contains a mixture of saturated water and
saturated steam at a temperature of 250 0C. The mass of the liquid
present is 9 Kg. Find the pressure, the mass, the specific volume,
the enthalpy, the entropy and internal energy using steam table
only.
With the help of P-V diagram and T-s diagram explain Otto cycle
clearly showing the pressure during which the heat is supplied and
rejected.
The minimum pressure and temperature in a Otto cycle are 100 kPa
and 27oC. The amount of heat added to the air per cycle is 1500
kJ/kg.
Determine the pressure and temperatures at all points of air
standard Otto cycle.
Calculate the specific work and thermal efficiency of the cycle
for a compression ratio of 8:1.
Explain how actual vapour compression refrigeration cycle
differs from an ideal vapour compression refrigeration cycle.
An ammonia vapour compression refrigerator operates with
evaporator pressure of 3.5 bar and condenser pressure of 15 bar.
Calculate ideal and actual COP also calculate the mass ow rate per
kW of refrigeration assuming that dry saturated vapour is delivered
by the compressor and liquid after condensation is sub cooled to
200C.
In an open cycle air refrigeration machine, air is drawn from a
cold chamber at -20C and 1 bar and compressed to 11 bar. It is then
cooled at this pressure, to the cooler temperature of 200C and then
expanded in expansion cylinder and returned to the cold room. The
compression and expansion are isentropic, and follows the law
pv1=constant. Sketch the p-v and T-s diagrams of the cycle and for
refrigeration of 15 tones, find:
Theoretical C.O.P;
Rate of the air in kg/min;
Piston displacement per minute in the compressor and
expander;
Theoretical power per ton of refrigeration.
A refrigerator working on bell-Coleman cycle operates between
pressure limits of 1.05 bar and 8.5bar. Air is drawn from the cold
chamber at 100C, compressed and it is cooled to 300C. Before
entering the expansion cylinder. The expansion and compression
follows the law pv1.3=constant. Determine the theoretical C.O.P. of
the system.
The piston of an oil engine, of area 0.0045 m2, moves downwards
75 mm, drawing in 0.0028 m3 of fresh air from the atmosphere. The
pressure in the cylinder is uniform during the process at 80 kPa,
while the atmospheric pressure is 101.325 kPa, the difference being
due to the low resistance in the induction pipe and the inlet
valve. Estimate the displacement work done by the air finally in
the cylinder.
Explain about the re-heating and refrigeration of a steam cycle
with help of neat diagrams?
Short Answer QuestionsUNIT-I1. What is a Thermodynamic system?2.
What is the difference between a closed system and an open
system?3. What is a Thermodynamic Cycle?4. What is the difference
between intensive and extensive properties?5. Can mass cross the
boundaries of a closed system? How about energy?6. What is a
quasi-equilibrium process? What is its importance in engineering?7.
What is the concept of continuum? How do you define density and
pressure usingthis concept?UNIT-II
What is a Zeroeth law of Thermodynamics?
Define Thermometric Property.
What is Thermometer?
What is a fixed point? What is a Standard Reference point in the
thermometry? Define it.
What is a Constant Gas Volume Thermometer? Why is it preferred
to Constant Pressure Gas thermometer?
What do you understand by Ideal Gas Temperature Scale?
How can the ideal gas temperature for the steam point be
measured?
How can the ideal gas temperature for the steam point be
measured?
How does Resistance thermometer measure temperature?
State First law of thermodynamics undergoing a cycle?
What is the property introduced by First law of
Thermodynamics?
State the first law for a closed system undergoing a change of
state.
Show that energy is a property of a system.
Define Internal Energy. How is energy stored in molecules and
atoms?
Differentiate between the standard symbols of E & U.
What is the difference between Heat and Internal Energy?
Define Specific Heat at Constant Volume and at Constant
Pressure.
What is PMM I? Why is it impossible?
Explain System Approach and Control volume Approach in the
analysis of a Flow process.
What is a Steady Flow process?
Under What condition S.F.E.E reduces to Eulers Equation.
How does Bernoullis Equation Compare with S.F.E.E?
What will be the velocity of a fluid leaving a nozzle if the
velocity of approach is very small?
Show that Enthalpy of a fluid before Throttling is equal to
After Throttling.
Write the General Energy Equation for a variable Flow
Process.
What is the System Technique in Bottle Filling Process?
Explain the Control Volume Technique in a variable Flow
process.
UNIT-III
What are the Limitations of First Law.
What is the qualitative difference between heat and work? Why
are the heat and work not completely interchangeable forms of
energy.
What is a Cyclic Heat Engine?
Explain a heat engine cycle performed by a closed system.
Explain the heat engine cycle performed by a steady flow
system.
Define the Thermal Efficiency of a heat engine cycle. Can this
be 100%?
Draw block diagram showing the four energy interactions of a
cyclic heat engine.
What is the thermal Energy Reservoir? Explain the terms Source
and Sink.
What is the mechanical energy reservoir?
Why can all processes in a TER and MER be assumed to be
quasi-static?
Give Kelvin-Plank Statement of Second Law of thermodynamics.
To produce net work in a thermodynamic cycle, a heat has to
exchange heat with two thermal reservoirs. Explain.
What is PMM II ? Why is it impossible?
Give the Clausius Statement of Second law of Thermodynamics.
Explain the operation of a cyclic Refrigeration plant with a
block diagram.
Define COP if a Refrigerator.
What is a Heat pump? How does it differ from a Refrigerator?
Consider the energy generated by a TV set. What is a suitable
choice for a thermal energy reservoir?
What are the four processes that make up the Carnot cycle?
What are the four processes that make up the reversed Carnet
cycle?
What is a cyclic process?
State alternative statements of the first law of
thermodynamics?
Can you use the same plant as a heat pump in winter and
refrigerator in summer? Explain.
Show that COP of a heat Pump is greater than the COP of a
refrigerator by Unity.
Establish the equivalence of Kelvin-Plank and Clausius
Statements.
What is a reversible process? How is this be a limiting
process?
All spontaneous processes are irreversible. Explain.
What are the causes of Irreversibility of a process.
Show that Heat Transfer through a finite temperature difference
is irreversible.
Explain perpetual motion of the third kind.
Demonstrate using Second law how friction makes a process
irreversible.
Explain the Carnot Heat Engine Cycle executed by (a) Stationary
System (b) a steady flow system.
What is a reversed heat engine?
Is the Third Law an extension of Second Law? Is it an
independent Law of nature ? Explain.
How does the efficiency of a reversible engine vary as the
source and sink temperatures are varied? When does the efficiency
become 100%?
What do you understand by Internal & external
Irreversibility?
Explain Mechanical, Thermal and Chemical Irreversibilities.
A Carnot engine with a fuel burning device as source and a heat
sink cannot be treated as reversible plant.
Show that Entropy is a property of a system.
How entropy change of a reversible process is is estimated? Will
it be different for an irreversible process between the same end
states?
Why Carnot Cycle on a T-S plot is a rectangle.
Giver the criteria of reversibility, irreversibility and
impossibility of a thermodynamic cycle.
What do you understand by the entropy principle?
When the system is in equilibrium, why would any conceivable
change in entropy is zero?
How did Rudolf Clausius summarize the first and second laws of
thermodynamics?
Show that transfer of heat through a finite temperature
difference is irreversible.
What are the causes of Entropy Increase?
Why is an isentropic process not necessarily an adiabatic
process?
What is the reversible adiabatic work for a steady flow system
when K.E and P.E changes are negligibly small? How is different
from that for a closed stationary system.
Why are the equations
T dS = dU + pdVTdS= dH - vdP Valid for any process between two
equilibrium states.What is the entropy generation in the isothermal
and adiabatic dissipation of work?
What do you understand by entropy transfer ? Why is entropy
transfer associated with heat transfer but not with work
transfer?
What do you understand by high grade energy and low grade
energy?
What is available energy and unavailable energy?
Who pronounced the concept of availability?
What is the available energy referred to a cycle?
What are Helmholtz Function and Gibbs Function?
What is the condition for exact differential?
Derive Maxwells Equations.
Explain Absolute Entropy and Third Law of
Thermodynamics.
UNIT-IV
What is a Pure Substance?
What do you understand by Saturation State?
What is triple point?
What is Critical state? Explain Critical pressure, critical
Volume of water and Critical Temperature.
What is normal boiling point?
Draw Phase Diagram for a Pure substance on p-T Coordinates, T-s
plot and h-s plot.
Why do isobars on Moiller diagram diverge from one another?
Why do isotherms of Moiller diagram become horizontal in the
super heated region at low pressures?
Explain Degree of Superheat and Subcooling.
What is the quality of steam and what are the different methods
of measurement of quality.
Explain the principle of operation of electric calorimeter.
Derive Clausius-Clapeyron Equation.
Show that the slope of the sublimation curve at the triple point
is greater than that of the vaporization curve.
UNIT-V
What is Avogadro's law?
What do you understand by Saturation State?
What is the Equation of State?
What is fundamental property of gases with respect to product
pv?
What is Universal Constant?
Define an ideal gas.
Show that for an ideal gas, the internal energy depends only on
its temperature.
Show that Enthalpy of an ideal gas is a function of temperature
only.
What are different forms of energy and How does free expansion
has zero work transfer?
Why can't a throttling calorimeter measure the quality if the
steam is very wet?
Define an ideal Gas.
What is Universal gas constant
What is an equation of state.
What is Boltzmann's Constant?
What is a poly tropic process?
Write down the Vanderwaals equation of state.
What are reduced properties.
What is Throttling ?
What is Free Expansion Process?
What is the generalized compressibility chart?
UNIT-VI1. What is Avogadro's law2. What do you understand by dry
bulb temperatures? 3. What do you understand by wet bulb
temperatures? 4. Define dew point temperature.5. What is an
adiabatic saturation process?6. What do you understand by higher
heating value and lower heating value of afuel?7. Explain adiabatic
flame temperature.8. What is the proportion of oxygen and Nitrogen
in atmospheric air on mass basis. 9. What is the proportion of
oxygen and Nitrogen in atmospheric air on Vol. basis. 10. State
third law of Thermodynamics11. What is stoichiometric excess and
deficient air?12. Define dry ness fraction of steam.13. Explain the
process of steam generation.14. Show the various stages during
steam generation on P-V and T-S diagrams.15. Define relative
humidity.]6. State Amagat's law of partial volumes.17. State
Dalton's law of partial pressures.18. What is meant by partial
volume of constituent in a mixture.19. What the relation between
the partial pressure of vapor and the saturation pressureof water
at the dew point temperature.20. Define specific humidity of an air
water vapor mixture.21. What is meaning of partial pressure of a
component in a mixture.22. If one mole of mono-atomic gas is mixed
with one mole of diatomic gas, whatwill be the molar heat capacity
at constant volume for the mixture.23. When do the DBT, WBT become
equal?24. What is Psychrometries?25. What are hygroscopic
materials?26. What do you understand by saturated air and
unsaturated air? 27. What is degree of saturation?28. What is
psychrometer?29. What is an adiabatic saturation process?30. What
is thermodynamic wet bulb temperature?31. What is the enthalpy of
an air vapor mixture?32. Why does the enthalpy of an air vapor
mixture remain constant during andadiabatic saturation process.32.
What is sensible heating or cooling?33. What is apparatus dew
point?34. Write down the Carrier's equation?35. Which properties of
air-water vapor mixtures are usually presented on apsychrometric
chart.36. Name the common reagent solutions used in Orsat apparatus
and what purposedoes each reagent solution serve.37. What is meant
by standard heat of a reaction?38. What is meant by theoretical air
fuel ratio?39. Assume complete combustion, write down the
combustion reaction for propane ifthe required oxygen is supplied
in the form of air?40. What is a cooling tower? How is it
specified? Where is it used?UNIT-VII
What is compression ration in 1. C Engines?
Write the equation for efficiency of Carnot cycle
State the four processes of the Carnot cycle.
State the four process of Otto cycle.
State the four process of diesel cycle.
What is mean effective pressure.
What is a mixed or duel cycle.
What is a SJ Engine and how it differs form a C.l Engine.
For the same compression ration and heat rejection which cycle
is more efficient:
Otto, Diesel or Duel.
What are cyclic and non cyclic heat engines? Give examples.
What is an air standard cycle.
Why are air standard cycles conceived?
What is the air standard cycle of S.I Engine?
What is a Compression ignition Engine?
Why is the compression ration of C.I Engine more than that of a
S.I engine?
How is the compression ration of S.I engine fixed.
What is a combined cycle?
What is the application of closed cycle gas turbine plant?
What are the basic components of a gas turbine plant?
Define the cut-off ratio in a diesel cycle
Why is it possible to use higher compression ratio in the diesel
cycle.
Why a certain class of heat engines are called internal
combustion engines.
In the Otto cycle, the combustion process is treated as &
constant volume energy
Addition process. Explain why?Why the combustion of fuel in a
diesel engine is assumed to occur at constant
pressure.Draw the block diagram of a steam power plant.
The thermal efficiency of the Otto cycle increases with
increasing compression
ratio. To achieve higher efficiency is it possible to increase
the compression ratio without any upper limit? Explain.
UNIT-VIII
What is refrigeration? How is ice and dry ice used for the
purpose of refrigeration?
What is Tonne of refrigeration?
Name a few refrigerants that are most widely used.
Show the block diagram of vapor compression refrigeration
system
What are the expansion devices used in a vapour compression
plant and when they are used.
Sketch the ideal vapor compression refrigeration cycle on a T -S
diagram.
How is a reversed Brayton cycle used for refrigeration.
Why is the COP of gas cycle refrigeration system low?
Why is gas cycle refrigeration preferred in aircraft.
Define tonne of refrigeration.
Show the Bell-Coleman cycle on P- V and T -S diagrams.
Why is it not possible to operate a power plant on a Carnot
cycle.
Why is it necessary to super heat the steam in the Rankine
cycle?
Show Rankine cycle on P- V and T -S diagrams.
Why is COP of a gas cycle refrigeration low?
Why is gas cycle refrigeration system preferred in air
craft?
What is absorption refrigeration cycle? Derive an expression for
maximum COP for this cycle.
What are the functions of analyzer and rectifier?
Code No.: CVR COLLEGE OF ENGINEERING
Autonomous - Affiliated to JNTUHB. Tech. II Year, I Semester
Regular Examinations, Nov/Dec - 2012Subject
Thermodynamics(Mechanical Engineering)
Time: 3hours Max. Marks: 75Answer any five questionsAll
questions carry equal marks- - -Instructions to the students: Use
of steam tables, Mollier diagram, Psychrometric Charts / Tables is
permitted.
Assume any missing data suitably and state the assumption in the
Answer Clearly.
A) Differentiate between Microscopic and Macroscopic approaches
in Thermodynamics.
B) Discuss the causes of irreversibility. Give some
examples.[9+6]
A) Apply Steady Flow Energy Equation for a Control Volume to a
subsonic Diffuser and obtain an expression for exit pressure
developed in terms of temperature.
B) Air at a temperature of 150C passes through a heat exchanger
at a velocity of 30 m/s where its temperature is raised at 800 0C.
It then enters a turbine with the same velocity of 30 m/s and
expands until the temperature falls to 650 0C. On leaving the
turbine, the air is taken at a velocity of 60 m/s to a nozzle where
it expands until the temperature has fallen o 500 0C. If the air
flow rates is 2 kg/s calculate, Rate of heat transfer to the air in
the heat exchanger.
Power output from the turbine, assuming no heat loss and
Velocity of air at exit from the nozzle, assuming no heat
loss.
Take the specific enthalpy of air as h = CpT, where Cp = 1005
J/kg 0K and T is in 0K.[6+9]
A) Derive Maxwells Relations. State its applications.
B) Plot Carnots Cycle on PV and TS diagrams and derive relation
for its efficiency. [7+8]
A reversible heat engine operates between two reservoirs at
temperatures of 873 0K and 313 0K. The engine drives a reversible
refrigerator, which operates between reservoirs at temperature 313
0K and 253 0K. the heat transfer to the heat engine is 2000 kJ and
the network output of the combined engine refrigerator plant is
360kJ.Evaluate the heat transfer to the refrigerator and the net
heat transfer to the reservoir at
313 0K.Reconsider (i) given that the efficiency of the heat
engine and the COP of the refrigerator are each 40% of their
maximum possible values.
A) Derive Clapeyron equation and state its application.
B) One kg of steam at 18 bar and 280 0C undergoes a constant
pressure process until the quality of becomes 0.5 dry. Find the
work done, the heat transferred and the change in entropy.
[8+7]
Process 1: Air initially at 100 kPa and 50 0C undergoes
reversible adiabatic compression such that its volume is reduced to
20% of its initial volume.
Process 2: Then 940 kJ/kg of heat is added to this air at
constant volume.Process 3: Process 2 is followed by reversible
adiabatic expansion upto initial volume.Process 4: Finally heat is
rejected at constant volume so as to reach the initial
condition.Draw the four processes on one PV diagram. Determine the
maximum temperature, and heat rejected per kg of air. Assume
adiabatic index of compression and expansion of 1.4 and constant
volume specific heat as 0.717 kJ/kg0 K.
A certain mass of moist air stream with Relative humidity 40%
and specific volume 0.096 m3/kg dry air is mixed adiabatically at
total pressure = 101325 Pa with another moist air steam at DBT =
360 C and Wet bulb depression = 150 C of double the mass compared
to first stream.
Find for the resultant mixture a) Specific humidity b) Specific
Enthalpy /kg dry air c) Relative humidity and d) Dew point
depression. Sketch the mixing process on Psychrometric Chart.
A) Derive the efficiency and MEP of Otto cycle.
B) An engine equipped with a cylinder having a bore of 12 cm and
a stroke of 40cm operates on an Otto cycle. If the clearance volume
is 1800 cm3, compute the air standard efficiency.[7+8]
