PROPERTIES OF WORKING FLUIDS

1
PROPERTIES OF WORKING FLUIDS

• SUBMITTED BY
• DIANA ALKEFLAWI

Prof.Dr. NAFIZ KAHRAMAN
2
TABLE OF CONTENTS

• 
  
  Page
• 1 Working fluid....
  1
• 1 Phase of working fluid......................
  ..................................................
  .......2
• 2 Composition properties..
  ..3
• 2.1 Working fluid constituents..
  .....4
• 2.2 Chemically reacting gas
  mixtures....,6
• 2.3 Burned and unburned mixture
  composition.7
• 3 Thermodynamic properties..
  .15
• 3.1 Thermodynamic charts.......
  ..18
• 3.1.1 Unburned mixture charts..
  ...18
• 3.1.2 Burned mixture
  charts............................................
  ...................................21
• 3.1.3 Relation between unburned and
  burned mixture charts..24
• 3.2 Tables of properties and
  composition.........26
• 3.3 Computer routines for property
  and composition calculations...29
• 4 Transport properties
  .32
• 4.1 Viscosity..
  ....33
• 4.2 Thermal conductivity...
  ...34
• 4.3 Diffusion process
  ..35
• 4.4 Others
  .36

-ii-
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1. Working Fluid
The working fluid of a thermodynamic system is
any fluid (including gases) which receives,
transports, and transfers energy in the system.
This research deals with models for the working
fluid -
Composition Properties
Models For The Working Fluid
Thermodynamic Properties
Transport Properties
1
4
1.1 Phase of a Working Fluid Table 1
Solid Liquid Gas
Definite volume Definite volume Indefinite volume
Definite shape Indefinite shape Indefinite shape
Molecules in fixed Molecules can move Molecules move
position and interact with each independently
other
Lowest energy per Intermediate energy per Highest energy per
molecule molecule molecule
Table 1 Solids, Liquids, and Gases NOTE A
change of phase is always accompanied by a change
of state, but a change of state may or may not
be accompanied by a change of phase. For example,
there are many unique states of water all of
which would be classified as the liquid phase of
the water.
2
5
2 COMPOSITION PROPERTIES
The composition of the working fluid ,which
changes during the engine operating cycle.The
unburned mixture for a spark ignition engine
during intake and compression consists of -
AIR
PREVIOUSLY BURNED GASES
FUEL
It is, therefore, a mixture of N2, O2, CO2, H2O,
CO, and H2 for fuel-rich mixtures, and fuel
(usually vapor). The composition of the
unburned mixture does not change significantly
during intake and compression. It sufficiently
accurate to assume the composition is frozen.
For the compression-ignition engine, the unburned
mixture prior to injection contains no fuel it
consists of air and previously burned gas.
AIR
PREVIOUSLY BURNED GASES
3
6
TABLE (2) 2.1 Working fluid constituents
PROCESS SPARK IGNITION ENGINE COMPRESSION IGNITION ENGINE
INTAKE AIR AIR
INTAKE FUEL RECYCLED EXHAUST
INTAKE RECYCLED EXHAUST RESIDUAL GAS
INTAKE RESIDUAL GAS
COMPRESSION AIR AIR
COMPRESSION FUEL VAPOR RECYCLED EXHAUST
COMPRESSION RECYCLED EXHAUST RESIDUAL GAS
COMPRESSION RESIDUAL GAS
EXPANSION COMBUSTION PRODUCTS (MIXTURE OF N2,H2O,CO2,CO,H2,O2,NO,OH,O,H,) COMBUSTION PRODUCTS (MIXTURE OF N2,H2O,CO2,CO,H2,O2,NO,OH,O,H,)
EXHAUST COMBUSTION PRODUCTS (MAINLY N2,CO2,H2O,AND EITHERO2(Ølt1) OR CO AND H2(Øgt1) COMBUSTION PRODUCTS (MAINLY N2,CO2,H2O,AND O2)
4
7
The combustion products or burned mixture gases,
during the combustion process and much of the
expansion process, are close to thermodynamic
equilibrium.
By this we mean that the chemical reactions, by
which individual species in the burned gases
react together, produce and remove each species
at equal rates. No net change in species
composition results.
CO ½ O 2 CO2
For example
Towards the end of the expansion process, the gas
composition departs from the equilibrium
composition recombination can no longer occur
fast enough to maintain the reacting mixture in
equilibrium.
During the exhaust process, reactions are
sufficiently slow so that for calculating
thermodynamic properties the composition can be
regarded as frozen.
5
8
2.2 CHEMICALLY REACTING GAS MIXTURES The
working fluids in engines are mixtures of gases.
Depending on the problem under consideration and
the portion of the engine cycle in which it
occurs chemical reactions may (1) be so slow
that they have a negligible effect on mixture
composition (the mixture composition is
essentially"frozen"). (2) be so rapid that the
mixture state changes and the composition remains
in chemical equilibrium (3) be one of the
rate-controlling processes that determine how the
composition of the mixture changes with time.
6
9
2.3 BURNED AND UNBURNED MIXTURE COMPOSITION
Typical residual fractions in spark-ignition
engines range from 20 percent at light load to 7
percent at full load. In diesels, the residual
fraction is smaller (a few percent) due to the
higher compression ratio, and in naturally
aspirated engines is approximately constant since
the intake is unthrottled. If the inducted
mixture is fuel and air (or air only)
the burned gas fraction (xb) in the unburned
mixture during compression the
residual fraction . In some engines, a fraction
of the engine exhaust gases is recycled to
the intake to dilute the fresh mixture for
control of NOx emissions.
7
10
Percent of exhaust gas recycled ( EGR)
? m ?
EGR() ? EGR ? ?100
? ?
mi
the mass of Exhaust Gas Recycled
mEGR mi
inducted mass per cycle
Burned gas fraction, xb xb ? mEGR
mc mi mr

• mr

mc
? (EGR /100)(1? xr ) ? xr
7
mc
the mass of charge trapped in the cylinder
mr
The residual mass
8
11
EXHAUST GAS RECIRCULATION (EGR) SYSTEM
4
9
12
Combustion equation (with equivalence ratio, ? )
written per mole O2
n
H O ? n CO
CO2 ? n
CO
H O 2
CO
? O ??N ?
??c ? 2(1 ? ? )?H
(1)
2
2
2
2
2

• n H ? n O ? n N

N2 2
O2 2
H2 2
? N/O molar ratio ( 3.773 for air) ?
4/(4y) ni moles of species i per mole O2
reactant
where
9
10
13
The n, are determined using the following
assumptions 1. For lean and stoichiometric
mixtures (Ø 1) CO and H2 can be
neglected. 2 For rich and stoichiometric
mixtures (Ø 1) 02 can be neglected. 3. For
rich mixtures, either (a) the water gas reaction

CO2 H2 CO H2O
Frequently, thermodynamic properties of unburned
and burned mixtures are expressed per unit mass
of air in the original mixture (for burned
mixture this is the mixture before combustion).
To obtain properties, we need the mass of
original air, per mole O2 in the mixture, which
is 32 28.16 ? Where ? the molar
N/O ratio (3.773 for air) with units of
kilograms per kilomole or pound-mass per
pound-mole.
11
14
Table 3 Unburned mixture composition
Species ni, moles/mole O2 reactant
? ? 1 ? ? 1
fuel O2 N2 CO2 H2O CO H2 Sum1 4(1? xb )(1? 2? )? / M f 4(1? xb )(1? 2? )? / M f 1 ? xb? 1 ? xb ? ? xb?? xb (?? ? c) 2xb (1? ? )? xb ?2(1? ?? ) ? c? 0 xbc 0 xb ?2(? ?1) ? c? nu nu 21
12
15
Table 4 burned gas composition under 1700 K
species ni, moles/moles O2 reactant ni, moles/moles O2 reactant
species ? ? 1 ? ? 1
CO2 H2O CO a H2 a O2 N2 Sum (nb) ?? 2(1? ? )? bsent ! 0 bsent ! 0 1 ? ? a ? (1? ? )? ?1?? ?? ? c 2(1? ?? ) ? c c 2(? ?1) ? c sent ! 0 ? (2 ? ? )? ??
b
12 Summation of moles above
16
Molecular weight
Equivalence ratio Figure 1 Molecular weight of
unburned and burned
isooctane-air mixtures as a function of fuel/air
equivalence ratio and burned gas fraction
23
14
17
3 THERMODYNAMIC PROPERTIES
Thermodynamic Properties of a Working Fluid
Pressure the ratio of the total force exerted by
the fluid to the total area to which the force is
applied it is force per unit area. Temperature
a measure of the average thermal energy of the
molecules of a substance a direct indication of
the average kinetic energy of the substances
individual molecules. Specific volume the ratio
of the volume occupied by the fluid to the mass
it possesses it is volume per unit
mass. Density the ratio of the mass possessed by
the fluid to the volume it occupies it is mass
per unit volume. Internal energy energy
possessed by the fluid due to the average kinetic
energy of the individual molecules of the fluid,
Enthalpy (h) - Sum of the internal energy and
flow energy of a substance. Unit BTU/lbm Entropy
(s) - Quantitative description of the
unavailability of energy for the performance of
work Unit BTU/lbmER
15
18
The models used for predicting the thermodynamic
properties of unburned and burned mixtures can be
grouped into the five categories listed in Table
(5).
UNBURNED MIXTURE BURNED MIXTURE
1 Single ideal gas throughout operating cycle with cv (and hence cp) constant Single ideal gas throughout operating cycle with cv (and hence cp) constant
2 Ideal gas cv,u constant Ideal gas cv,b constant
3 Frozen mixture of ideal gases cv,i(T) Frozen mixture of ideal gases cv,i(T)
4 Frozen mixture of ideal gases cv,i(T) Approximations fitttd to equilibrium thermodynamic propertie
5 Frozen mixture of ideal gases cv,i(T) Mixture of reacting idealgases in thermodynamic equilibrium
Note Subscripts i, u, and b denote species i in
the gas mixture, the unburned mixture, and burned
mixture properties, respectively.
19
The first category is only useful for
illustrative purposes since the specific heats of
unburned and burned mixtures are significantly
different. While the specific heats of the
working fluids increase with increasing
temperature in the range of interest, a
constant-specific-heat model can be matched to
the thermodynamic data over a limited temperature
range. This approach provides a simple analytic
model which can be useful when moderate accuracy
of prediction will suffice. Approximations to
thermodynamic equilibrium calculations are
useful because of the savings in computational
time, relative to full equilibrium calculations,
which can result from their use. Values of
thermodynamic properties of unburned and burned
mixtures relevant to engine calculations are
available from charts, tables, and algebraic
relationships developed to match tabulated data.
17
20
3.1 THERMODYNAMIC CHARTS
3.1.1 UNBURNED MIXTURE CHARTS
The thermodynamic properties of each unburned
fuel-air mixture are represented by two charts.
The first chart is designed to relate the mixture
temperature, pressure, and volume at the
beginning and at the end of the compression
process the second gives the mixture internal
energy and enthalpy as functions of
temperature. The following assumptions are
made 1. The compression process is reversible
and adiabatic.
2. The fuel is in the vapor phase. 3. The mixture
composition is homogeneous and frozen (no
reactions between the fuel and air). 4. Each
species in the mixture can be modeled as an ideal
gas. 5. The burned gas fraction is zero.
18
21
Figure 2 Isentropic compression functions, ? and
?, as function of temperature for unburned
isooctane-air mixtures. Units J/kg air?K.
22
hs
us
Figure 3 Sensible enthalpy and internal energy of
unburned isooctane-air mixtures as function of
temperature. UnitskJ/kg air in mixture.
23
3.1.2 BURNED MIXTURE CHARTS
The primary burned mixture charts are for the
products of combustion at high temperatures., for
the working fluid during the expansion process.
The following assumptions are made 1. Each
species in the mixture can be modeled as an ideal
gas. 2. The mixture is in thermodynamic
equilibrium at temperatures above 1700 K the
mixture composition is frozen below 1700 K. 3.
Datum. At the datum state of 298.15 K and 1 atm
the chemical elements in their naturally
occurring form (N2, 02, H2 as diatomic gases and
C as solid graphite) are assigned zero enthalpy
and entropy.
21
24
As the burned gases in an engine cylinder cool
during the expansion process, the composition
eventually "freezes"-becomes fixed in composition
because the chemical reactions become extremely
slow. The equilibrium assumption is then no
longer valid. For lean and stoichiometric
mixtures this distinction is not important
because the mole fractions of dissociated species
below this temperature are small.
For rich mixtures, a frozen composition must be
selected and used Because the mole fractions of
CO2, CO, H20, and H2 would continue to change if
equilibrium is assumed as the temperature
decreases. Internal energy and enthalpy, per
kilogram of air in the original mixture, of the
frozen burned mixture are plotted against
temperature.
22
25
Figure 4 Internal energy versus entropy
chart51 for
equilibrium burned gas mixture,isooctane fuel,
equivalence ratio 1.0
26
3.1.3 Relation between unburned and burned
mixture charts
Given unburned mixture at T1 , p1 , v1 , the
combustion could be considered as

1. constant-volume adiabatic combustion
2. constant-pressure adiabatic combustion

Charts
Burned

• Unburned
• Compression process
• Enthalpy and internal energy of the mixture 0
  at T 298 K

- Expansion process
- Enthalpy and entropy of the
chemical elements in their
naturally occurring form form
( , and
and C (solid))55are
O2 N2
H 2
assigned zero
24
27
GOING FROM UNBURNED TO BURNED
Combustion
End of compression (unburned)
Start of expansion (burned)
Adiabatic
Constant volume
Constant pressure
ub uu hb hu Relations between unburned and
burned
56
25
28
3.2 TABLES OF PROPERTIES AND COMPOSITION
Tables of thermodynamic properties of air are
useful for analysis of motored engine operation,
diesels and compressors. Keenan, Chao, and Kaye's
Gas tables are the standard reference for the
thermodynamic properties of air at low pressures
(i.e., at pressures substantially below the
critical pressure when the ideal gas law is
accurate). These gas tables are in U.S. and SI
units. A set of tables for air in SI units has
been prepared by Reynolds following the format of
the Keenan et al. tables.
h enthalpy, kJ/kg u internal energy, kJ/kg
T ? ? ( Cv/T) dT, kJ,kg.K 0 T
Ø ? (Cp/T) dT, kJ,kg.K 0 pr
relative pressure vr relative volume cp
specific heat at constant pressure, kJ/kg K cv
specific heat at constant volume, kJ/kg K .
? ratio of specific heats all as a function of
T(K). Ø is the standard state entropy at
temperature T and 1 atm pressure, relative to the
entropy at 0 K and 1 atm pressure
26
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Table -6 Ideal gas properties of air.
Temp (K) Cv (kJ/kg-K) Cp (kJ/kg-K) U (kJ/kg) h (kJ/kg) T ?(Cp( T)/T)dt Tref (kJ/kg-K)
200 0.7153 1.002 142.7 200.1 5.299
220 0.7155 1.003 157.0 220.2 5.394
240 0.7158 1.003 171.3 240.2 5.481
260 0.7162 1.003 185.6 260.3 5.562
280 0.7168 1.004 200.0 280.3 5.636
300 0.7177 1.005 214.3 300.4 5.705
320 0.7188 1.006 228.7 320.5 5.770
340 0.7202 1.007 243.1 340.7 5.831
360 0.7219 1.009 257.5 360.8 5.889
380 0.7239 1.011 272.0 381.0 5.944
400 0.7262 1.013 286.5 401.3 5.995
420 0.7289 1.016 301.0 421.6 6.045
440 0.7318 1.019 315.6 441.9 6.092
460 0.7350 1.022 330.3 462.3 6.137
480 0.7385 1.026 345.0 482.8 6.181
500 0.7423 1.029 359.8 503.3 6.223
520 0.7462 1.033 374.7 524.0 6.263
540 0.7504 1.037 389.7 544.7 6.302
560 0.7547 1.042 404.7 565.5 6.340
580 0.7592 1.046 419.9 586.3 6.377
600 0.7638 1.051 435.1 607.3 6.412
620 0.7685 1.055 450.4 628.4 6.447
640 0.7732 1.060 465.8 649.5 6.480
660 0.7780 1.065 481.3 670.8 6.513
30
Tables giving the composition and thermodynamic
properties of combustion products have been
compiled. They are useful sources of property and
species concentrations data in burned gas
mixtures for a range of equivalence ratios,
temperatures, and pressures. Summary information
on four generally available sets of tables
is Keenan, Chao and Kay Reynolds
General Electric AGARD
The most extensive set of tables of
combustion product composition and thermodynamic
properties is the AGARD Set,.
28
31
3.3 COMPUTER ROUTINES FOR PROPERTY AND
COMPOSITION CALCULATIONS
The most complete models are based on polynomial
curve fits to the thermodynamic data for each
species in the mixture and the assumptions that
(1) the unburned mixture is frozen in
composition (2) the burned mixture is in
equilibrium. The approach used as the basis for
representing JANAF table thermodynamic datas in
the NASA equilibrium prograrn.
29
32
Fig 5 Specific heat at constant pressure , cp/R
as function of temperature for species
CO2,H2O,O2,H2 and CO(from JANAF table)
30
33
At the burned mixture ,the internal energy and
gas constant of undissociated combustion products
were first described by polynomials in gas
temperature. The second step was to limit the
range of T and p to values found in internal
combustion engines. Then the deviations between
the equilibrium thermodynamic property data
published by Newhall and Starkman. and the
calculated nondissociated values were fitted by
an exponential function of T, p, and Ø. For Ø
1, a single set of equations resulted.
For Ø 1, sets of equations were developed, each
set applying to a specific value of equivalence
ratio. In general, the fit for internal energy
is within 2(1/2) percent over the pressure and
temperature range of interest and the error over
most of the range is less than 1 percent.
31
34
4 TRANSPORT PROPERTIES
The processes by which mass, momentum, and energy
are transferred from one point in a system to
another are called rate processes. In internal
combustion engines, examples of such processes
are
fuel-air mixing friction at a gas/solid interface
heat transfer between gas and the walls of the
engine combustion chamber
evaporation of liquid fuel
In engines, most of these processes are turbulent
and are therefore strongly influenced by the
properties of the fluid flow. However,turbulent
rate processes are usually characterized by
correlations between dimensionless numbers (e.g.,
Reynolds, Prandtl, Nusselt numbers, etc.), which
contain the fluid's transport properties of
viscosity, thermal conductivity, and diffusion
coefficient as well as the flow properties
32
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4.1 VISCOSITY
For such a gas, the measured temperature
dependence can only be explained with more
sophisticated models for the intermolecular
potential energy than that of a hard sphere.
Effectively, at higher temperatures, the higher
average kinetic energy of a pair of colliding
molecules requires that they approach closer to
each other and experience a greater repulsive
force to be deflected in the collision. As a
result, the molecules appear to be smaller
spheres as the temperature increases.
33
36
4.2 THERMAL CONDUCTIVITY
An expression for the thermal conductivity k of a
monatomic hard-sphere gas can be derived from an
analysis of the thermal equivalent of plane
Couette flow.
' In Couette flow, the fluid is contained between
two infinite plane parallel surfaces, one at rest
and one moving with constant velocity.In the
absence of pressure gradients, the fluid velocity
varies hearly across the distance between the
surfaces.
Experimental measurements for such polyatomic
gases is the sum of the translational specific
heat and the specific heat due to internal
degrees of freedom. It was suggested by Eucken
that transport of vibrational and rotational
energy was slower than that of translational
energy.
Gas atoms moving randomly through a surface.
34
37
4.3 DIFFUSION PROCESS
A similar analysis of a binary diffusion process,
where one gas diffuses through another, leads to
an expression for the binary diffusion
coefficient Dij. Dij is a transport property of
the gas mixture composed of species i and j,
defined by Fick's law of molecular diffusion.
Dij (3/ 16nd2)(2kT/ p mij)1/2
35
38
4.4 OTHERS
A more rigorous treatment of gas transport
properties, based on more realistic intermolecular
potential energy models, can be found in
Hirschfelder who also present methods for
computing the transport properties of mixtures
of gases. The NASA computer program
"Thermodynamic and Transport Properties of
Complex Chemical system computes the viscosity,
thermal conductivity.
Prandtl number in addition to the thermodynamic
calculations for high-temperature equilibrium and
frozen gas mixtures. Approximate correlations
were then fitted to the calculated data of
viscosity and Prandtl number. The principal
advantage of these correlations is computational
speed.
The viscosity of combustion products is almost
independent of pressure.
36
39
A good fit to the data for lean combustion
product mixtures was the following
Pr 0.05 4.2(? -1) 6.7 (? 1 )² Ø 1
For rich mixtures the following equation is a
good fit to the equilibrium values of Pr using
equilibrium values of v, for temperature greater
than 2000K
Pr 0.05 4.2(? -1) 6.7 (? 1 )² 1ltØ
4 1 0.015 10(-6)(ØT)²
37
40
5 EXHAUST GAS COMPOSITION
the composition of engine exhaust gases can not
easily be calculated Why?
1- At high temperatures (during combustion and
the early part of the expansion stroke) the
burned gas composition corresponds closely to the
equilibrium composition at the local temperature,
pressure, and equivalence ratio. 2- During the
expansion process, recombination reactions
simplify the burned gas composition. 3-late in
the expansion stroke and during exhaust blowdown,
the recombination reactions are unable to
maintain the gases in chemical equilibrium and,
in the exhaust process, the composition becomes
frozen. 4- not all the fuel which enters the
engine is fully burned inside the cylinder the
combustion inefficiency even when excess air is
present is a few percent. 5- the contents of
each cylinder are not necessarily uniform in
composition, and the amounts of fuel and air fed
to each cylinder of a multicylinder engine are
not exactly the same. For all these reasons, the
composition of the engine exhaust gases cannot
easily be calculated.
38
41
SPARK-IGNITION ENGINE DATA
On the lean side of stoichiornetric,as Ø
decreases, CO2 concentrations fall, oxygen
concentrations increase, and CO levels are low
but not zero. On the rich side of
stoichiometric, CO and H2 concentrations rise
steadily as Ø increases and CO2
concentrations fall. 0, levels are low but are
not zero. At stoichiometric operation, there is
typically half a percent 0, and three-quarters of
a percent CO
Mole fractions of
Fuel-air equivalence ratio
Figure 7 Spark-ignition engine exhaust gas
composition data in mole fraction as a function
of fuel/air equivalence ratio.
67
42
Hydrogen concentrations in engine exhaust are not
routinely measured. However, when the mixture is
oxygen-deficient-fuel rich-hydrogen is
present with CO as an incomplete combustion
product. This figure summarizes the available
data on H2 concentrations plotted as a function
of C0.
Hydrocarbon fuels Approx 85 c
Hydrogen by vol
Carbon monoxide by vol
en68gine
Figure 8 Hydrogen concentration in spark-ignition
exhaust as a function of carbon monoxide
concentration. Units percent by volume.
43
DIESEL EXHAUST DATA.
Since diesels normally operate significantly
lean of stoichiometric (Ø0.8) and the diesel
combustion process is essentially complete, their
exhaust gas composition is straightforward. This
figure shows that 02 and CO2 concentrations vary
linearly with the fuel/air equivalence ratio over
the normal operating range. Diesel emissions ,of
CO and unburned HC are low.
Mole fraction
Exhaust equivalence ratio
Figure 9 Exhaust gas composition from several
diesel engines in mole fractions on a dry basis
as a function of fuel/air equivalence ratio.
44
6 Equivalence Ratio Determination from Exhaust
Gas Constituents Exhaust gas composition depends
on the relative proportions of fuel and air fed
to the engine, fuel composition, and completeness
of combustion. These relationships can be used to
determine the operating fuel / air equivalence
ratio of an engine from a knowledge of its
exhaust gas composition. A general formula for
the composition of fuel can be represented as
CnHmOr. For conventional petroleum-based fuels,
oxygen will be absent for fuels containing
alcohols, oxygen will be present. The overall
combustion reaction can be written as Fuel
oxidizer ? products The fuel is CnHmOr the
oxidizer is air (02 3.773N2). The products are
CO2,H2O, CO, H2, O2, NOx, N2, unburned
hydrocarbons (unburned fuel and products of
partial fuel reaction), and soot particles (which
are mainly solid carbon). The amount of solid
carbon present is usually sufficiently small for
it to be omittedfrom the analysis.
42
45
7 Effects of Fuel/ Air Ratio Nonuniforrnity
In spark ignition engines operating relatively
close to stoichiometric
For diesel engines the variations of major
exhaust gas species concentrations with fuel /
air equivalence ratio are linear so the effects
of any nonuniformities are not apparent in this
manned
43
46
REFERENCES

• THERMODYNAMIC PROPERTIES OF WORKING FLUID OF
  INTERNAL COMBUSTION ENGINE/ Krzystof
  Z.Mendera / Journal of KONES Internal combustion
  engines 2004.vol.11.NO.34

• INTERNAL COMBUSTION ENGINE FUNDAMENTALS / John
  B. Heywood

• A review of thermodynamic cycles and working
  fluids for the conversion of low-grade heat
  /Huijuan Chen, D. Yogi Goswami , Elias K.
  Stefanakos / journal homepage www.elsevier.com/lo
  cate/rser

• An analysis of the thermodynamic cycle and
  possible working fluids for a space heat
  rejection system by George C. Bucher

• thermodynamic and transport combustion
  properties of hydrocarbons with air / Sanford
  Gordon / NASA Technical paper 1906 / July 1982

44