Study and Analysis of the Effect of Operating/Performance Parameters on the Thermal Efficiency of Gas Turbine Power PlantStudy and Analysis of the Effect of Operating/Performance Parameters on the Thermal Efficiency of Gas Turbine Power Plant

ISSN 2393-8471
International Journal of Recent Research in Civil and Mechanical Engineering (IJRRCME)
Vol. 2, Issue 1, pp: (213-224), Month: April 2015 – September 2015, Available at: www.paperpublications.org
Page | 213
Paper Publications
Study and Analysis of the Effect of
Operating/Performance Parameters on the
Thermal Efficiency of Gas Turbine Power
Plant
1
Mr. Satyendra Dubey, 2
Mr. Neeraj
Abstract: The main objective of this dissertation is to identify the barriers in increasing the thermal efficiency of
Gas Turbine based power plants i.e. GTPP. The barriers in technology transfer implementation have been
identified from literature review. These barriers may be of market, cultural, human resource .management,
financial, economical, attitudinal, environmental, geographical and technological type. Technology transfer
barriers threats the movement of physical structure, knowledge, skills, organization value and capital from the
developed to developing countries. Clear understanding of these barriers may help the practitioners to find out
various ways to deal with them. This may further facilitate successful implementation of technology transfer.
Technology transfer may be said to be successful if Transferor (seller) and the transferee (buyer) can effectively
utilize the technology for business gain. The transfer involves cost and expenditure that should be agreed by the
transferee and transferor. The process is affected by various factors that hinder Technology Transfer. These
factors named Barriers. In the present work, Interpretive Structure Modeling(ISM) is used for the analysis and
comparison of various factors important for Technology Transfer. The important parameters are identified and
self-interaction matrixes proposed with the help of Interpretive Structure Modeling which evaluates the inhibiting
power of these parameters. This index can be used in comparison of different factors responsible for Technology
Transfer processes.
Keywords: Gas Turbine Power Plant, Interpretive Structure Modeling(ISM), increasing the thermal efficiency of
Gas Turbine based power plants i.e. GTPP.
1. INTRODUCTION
Power generation is an important issue today. Gas turbines have turned out to be one of the most interesting techniques
for electric power generation. It can be used in several different modes in industries such as power generation, oil and gas,
process plants, aviation as well as domestic and smaller related industries.
The use of gas turbine for electrical power generation has changed dramatically in recent years. In 1970s, gas turbines
(particularly in Great Britain and North America) were primarily used for peaking and emergency application; aero
derivative units with a heavy duty power turbine were widely used. One of the outstanding advantages of this type was its
ability to produce full power in cold in less than 2 minutes, although this capability should be used only for emergencies
because thermal shock will greatly reduce the time between overhauls.
In India, thermal power is the largest source of power. About 75% of electricity consumed in India is generated
by thermal power plants. More than 50% of India's commercial energy demand is met through the country's
vast coal reserves. Public sector undertakings, National Thermal Power Corporation and several other state level power
generating companies are engaged in operating coal based thermal power plants. Apart from NTPC and other state level
operators, some private companies are also operating the power plants. As on July 31, 2010, and as per the Central

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Electricity Authority the total installed capacity of Coal or Lignite based power plants in India are 87093.38 MW. While
in March 2009, the installed power generation capacity of India stood at 147,000 MW and the total demand for electricity
in India is expected to cross 950,000 MW by 2030.
The state of Maharashtra is the largest producer of thermal power in the country. India is one of the pioneering states in
establishing hydro-electric power plants. The power plant at Darjeeling and Shimla (Shivanasamudra) was established in
1898 and 1902 respectively and is one of the first in Asia. The installed capacity as of 2008 was approximately 36647.76
MW. There are different types of Thermal power plants based on the fuel used to generate the steam such
as coal, gas, Diesel etc. As on July 31, 2012, and as per the Central Electricity Authority the total installed capacity
of types of power plants in India are plotted as:
Fig. 1.1: All India generating installed capacity (MW)
Capital costs of generation plants vary according to the plant basis. Typical costs (2010) per MW are
 Coal-based plant: INR 3.8 to 4 crore.
 Gas-based plant: INR 3.5 crore.
 Hydro: INR 5 crore.
 Wind: INR 5-6 crore.
 Nuclear: INR 6 crore (going by the project cost for PWR and PHWR reactors).
Of the various means of producing mechanical power the turbine is in many respects the most satisfactory. The absence
of reciprocating and rubbing members means that balancing problems are few, that the lubricating oil consumption is
exceptionally low, and that reliability can be high the inherent advantages of the turbine were first realized using water as
the working fluid, and hydro-electric power is still a significant contributor to the world’s energy resources. Around the
turn of the twentieth century the steam turbine began its career and it has become the most important prime mover for
electricity generation. Steam turbine plants producing well over 1000 MW of shaft power with an efficiency of 40 per
cent are now being used. Steam turbines were widely used in marine applications, but could not compete with the thermal
efficiency of the diesel engine when fuel costs became important in the mid1970s; they are still used, however, in nuclear-
power aircraft carriers and submarines. In spite of its successful development, the steam turbine does have an inherent
disadvantage. It is that the production of high-pressure high-temperature steam involves the installation of bulky and
expensive steam generating equipment, whether it be a conventional boiler or nuclear reactor.
The significant feature is that the hot gases produced in the boiler furnace or reactor core never reach the turbine; they are
merely used indirectly to produce an intermediate fluid, namely steam. A much more compact power plant results when
the water to steam step is eliminated and the hot gases themselves are used to drive the turbine. Serious development of
the gas turbine began not long before the Second World War with shaft power in mind, but attention was soon transferred
to the turbojet engine for aircraft propulsion. The gas turbine began to compete successfully in other fields only in the mid
1950s, but since then it has made a progressively greater impact in an increasing variety of applications.
The gas turbine engine is a complex assembly of a variety of components that are designed on the basis of aero
thermodynamic laws. The design and operation theories of these individual components are complicated. The complexity

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of aero thermodynamic analysis makes it impossible to mathematically solve the optimization equations involved in
various gas turbine cycles. At the early stage of gas turbine developments, experimental tests of prototypes of either the
whole engine or its main components were the only method available to determine the performance of either the engine or
of the components. However, this procedure was not only costly, but also time consuming. Therefore, mathematical
modeling using computational techniques were considered to be the most economical solution. A gas turbine engine
essentially consists of the following component parts: (i) intake, (ii) compressor, (iii) combustion chamber, (iv) turbine,
and (v) engine auxiliaries, such as fuel pump, lubrication pump, electrical power supply, starting gear, and control system.
In order to produce an expansion through a turbine a pressure ratio must be provided, and the first necessary step in the
cycle of a gas turbine plant must therefore be compression of the working fluid. If after compression the working fluid
was to be expanded directly in turbine, and there were no losses in either component, the power developed by the turbine
would just equal that absorbed by the compressor. Thus if the two were coupled together the combination would do no
more then turn by the addition of energy to raise the temperature of the working fluid prior to expansion. When the
working fluid is air a very suitable means of doing this is by combusting of fuel in the air which has been compressed.
Expansion of the hot working fluid then produces a greater power output from the turbine, so that it is able to provide a
useful output in addition to driving the combustion turbine in its simplest form. The three main components are a
compressor, combustion chamber and turbine, connected together.
In practice, losses occur in both the compressor and turbine which increase the power absorbed by the compressor and
decrease the power output of the turbine. A certain addition to the energy of the working fluid, and hence a certain fuel
supply, will therefore be required before the one component can drive the other. This fuel produces no useful power, so
that the component losses contribute to a lowering of the efficiency of the machine. Further addition of fuel will result in a
useful power output, although for a given flow of air there is a limit to the rate at which fuel can be supplied and therefore
to the net power output. The maximum fuel/air ratio that may be used is governed by the working temperature of the
highly stressed turbine blades, which temperature must not be allowed to exceed a certain critical value. This value
depends upon the creep strength of the materials used in the contrition of the turbine and the working life required.
2. PROBLEM FORMULATION
From the literature, it is found that various researchers determined the individual effect of performance parameters on
thermal efficiency of a GTPP, but they did not consider the interrelations/interdependencies of parameters. Also they did
not consider the most critical factor or order of criticality for performance parameters effecting the thermal efficiency of
gas turbine power plant which leads to develop a unified approach, which will enable power plant development team to
consider all the attributes and their relative importance concurrently in an integrated manner for optimum selection of a
power plant. Also, this research will be helpful in developing a suitable permanent index. The minimum and maximum
values of the permanent index give us an overview of the index value between which the efficiency of power plant may
vary.
3. OBJECTIVE
The objective of present research work is to analyze the effect of Operating /performance Parameters on the thermal
efficiency of Gas Turbine Power Plant. Also it is useful for finding the critical factor among different performance
parameters of GTPP.
4. MATHEMATICAL MODELLING
The mathematical modeling of gas turbine power plant/ system for the proposed work can be explained in two phases viz.
(1) Modeling of gas turbine
(2) Modeling of graph theory
Modeling of gas turbine:
Although thermodynamic / mathematical modeling of gas turbine is done by various researchers as seen in literature
review, but for the better understanding of the present research work the thermodynamic modeling can be explained as:

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AIR COMPRESSOR:
In a gas turbine system, the intake air is initially compressed in the compressor to increase its pressure and temperature.
The performance of the compressor significantly affects the overall performance of the gas turbine power plant. Since, the
energy transfer during the flow of air compressor takes place, the thermodynamic as well as aerodynamic and mechanical
design and factors affecting these parameters play a significant role in the performance of the compressor. The various
attributes identified effecting the compressor design and performance are:-
1. Types of compressor (centrifugal or axial flow )
2. Design of inlet guide vanes
3. Compressor pressure ratio Stage temperature rise
4. No. of stages
5. Rotational speed
6. Type and no. of blade
7. Weight of rotor
8. Blades efficiency
9. Isentropic efficiency of compressor
10. Mass flow of air
Mass of the air entering the compressor is also effected by the ambient air temperature also. As the ambient air
temperature is increased, mass of the air entering the compressor also increases.
The ideal and actual processes on the temperature-entropy diagram are represented in full and dashed line respectively as
shown in figure 2(b).
The compressor pressure ratio (rp) can be defined as (Al-Sayed, 2008):
(3.1)
Where, p1 and p2 are compressor inlet and outlet air pressures, respectively.
It is assumed that the compressor efficiency is represented by 𝜼�c. The isentropic efficiency for compressor in the range of
85 to 90٪ is expressed as (Rahman et al., 2011):
Isentropic compressor efficiency, (3.2)
Where T1 and T2 are compressor inlet and outlet air temperature respectively, and T2s compressor isentropic outlet
temperature.
The final temperature of the compressor is calculated from equation (3.3) (Rahman et al., 2011):
(3.3)
Where 𝛾 is adiabatic index for air. So, the work of compressor (Wc) when blade cooling is not taken in to account can be
calculated [11] as:
(3.4)
Where is specific heat of air and� is the mechanical efficiency of compressor.
2
1
p
p
r
p

2 1
2 1
s
c
T T
T T

 

1
2 1
1
1
p
c
r
T T


 
 
  
  
 
paC m
1
1
1 1pa p
C
m
C T r
W



 
  
 
 


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5. COMBUSTION CHAMBER
The air with pressure and high temp. as received from the exit manifold of the compressor is fed to the combustions
chamber in atomized form. Due to high temperature of air, the fuel droplets get ignited and generate thermal energy. Due
to which the temp. of the hot fluid medium in the combustor increases. Higher is the peak temp achieved in the
combustion chamber, higher is the efficiency of the gas turbine. Since, the peak firing temperature is achieved with in
combustion chamber, it’s become essential to design the combustor to perform for peak temperature loadings.
It is clearly important that combustor developments should keep pace with improvements in other key engine
components. Thus, reduction of combustor size and weight will remain an important requirement for aero engines, where
as the continuing trend toward higher turbine inlet temperatures will call for a closer adherence to the design temperature
profile at the turbine inlet. Simultaneously, the demand for greater reliability, increased durability, and lower
manufacturing, development, and maintenance costs seems likely to assume added importance in the future. To meet these
challenges, the search goes on for new materials and new methods of fabrication to simplify basic combustor design and
reduce cost. The search has already led to the development of advanced wall-cooling techniques and the widespread use
of thermal barrier refractory coatings within the combustion liner.
The various attributes affecting the design and performance of combustion system are:-
1. Type of Combustor
2. Combustor loading
3. Combustor inlet temperature
4. Combustor line material properties
5. Nature of fuel
6. Combustor efficiency
7. Combustor Pressure loss
8. Peak Temperature combustor
9. Combustion Stability
10. NOx emission level
It is desired that NOx emission level in the plant should be as low as possible. As the cycle pressure ratio increases
concentration of nitrogen get changed. In the similar manner cycle pressure ratio effects the concentration of other
constituents also.
From the energy balance in the combustion chamber:
(3.5)
Where, ma is air mass flow rate (Kg/s), mf is air mass flow rate (Kg/s), LHV is low heating value, T3 = TIT = turbine inlet
temperature, Cpf is specific heat of fuel and Tf is temperature of fuel.
After manipulating equation (5), the air to fuel ratio (AFR) is expressed as:
(3.6)
6. GAS TURBINE
The Heat Content of the gases obtained at the exit of the combustor is converted into work output through energy
transformation in the gas turbine. The performance of the gas turbine in the system is measured in terms of several
attributes and is governed by the attributes of other matching turbo machinery components within the system. The design
of various subsystems of the turbine contributes in the desired gas turbine performance. The various attributes as
 2a pa f f pf f a f pgm C T m LHV m C T m m C TIT   
2
pga
f pg pa
LHV C TITm
AFR
m C TIT C T
 
 
 

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identified which affect the design and performance of the gas turbine taking thermodynamics, aerodynamic and
mechanical design constraints in to account are:
1. Degree of Reaction
2. Turbine inlet Temperature
3. Gas turbine expansion ratio
4. Number of Blades
5. Blade Efficiency
The isentropic efficiency for turbine in the range of 85 to 90٪ is expressed as (Rahman et al., 2011):
Isentropic turbine efficiency, (3.7)
Where T3 and T4 are turbine inlet and outlet air temperature respectively, and T4s turbine isentropic outlet temperature.
7. THERMAL EFFICIENCY OF GAS TURBINE POWER PLANT
Factors related to the efficiency may be identified either with the help of thermodynamic model of plant or with the help
of experts in this area. Thermo economic model gives an optimum solution for best efficiency and cost. The graph
theoretic mathematical model is a proven tool for the understanding of the plant as a whole, its systems, subsystems, and
their interconnections/interdependences (visual analysis and synthesis of the plant, identification of critical components
and critical interconnections, and so on). The graph theoretic model can also include human beings (operators,
manufacturer, designers, maintenance personnel, engineers, and managers) and environmental aspects. The procedure
permits the development of a model of the plant or its systems/subsystems or sub subsystems of each subsystem up to
component level. Before understanding the concept of thermal efficiency we have to understand the basic cycle operation
of gas turbine. Almost all the gas turbines works on Brayton cycle which consist of four processes namely:
(a) Process (1-2) – isentropic compression of air
(b) Process (2-3) – constant pressure energy addition
(c) Process (3-4) – isentropic expansion
(d) Process (4-1) – constant pressure energy rejection
The pressure-volume (P-V) and temperature-entropy (T-S) diagrams are shown in fig. 3.1 (a) and 3.1 (b):
Fig. 3.1 (a): P-V diagram Fig. 3.1 (b): T-S diagram
3 4
3 4
t
s
T T
T T

 


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According to steady flow energy equation,
From figure 2(a)
Heat added,
Heat rejected, q41 =
Thermal efficiency, =
ℎ𝑒𝑎𝑡�𝑎𝑑𝑑𝑒𝑑−ℎ𝑒𝑎𝑡�𝑟𝑒𝑗𝑒𝑐𝑡𝑒𝑑
ℎ𝑒𝑎𝑡�𝑎𝑑𝑑𝑒𝑑
(3.8)
For isentropic processes
(3.9)
(3.10)
(3.11)
8. METHODOLOGY
The Graph theoretic approach evaluates the permanent qualitative index of a gas turbine power plant in terms of single
numerical index, which takes into account the individual effect of various performance parameters and their
interdependencies while analyzing and evaluating the GTPP. The various steps of the proposed approach, which would be
helpful in evaluation of the GTPP, are enlisted in sequential manner as below;
1. Identify the various performance parameters (attributes) which affect the thermal efficiency of the GTPP
2. After the identification of contributing parameters, their interrelation / interdependences are considered.
3. Develop a digraph by considering attributes (performance parameters) as nodes and the interrelation of attributes as
edges.
4. Develop a performance parameter matrix on the basis of digraph developed in step 3.This will be of size N × N, with
diagonal elements representing performance parameters and the off-diagonal elements representing interaction among
them.
5. Obtaining the permanent function from the permanent matrix to characterize the gas turbine power plant /gas turbine
system.
6. Assign the quantitative value for the attributes (performance parameters) and their relative importance (interrelation).
pq mC dT
 
1
23 3 2 1
1
1
p
p pa
c
r
q mC T T C T


 
 
    
 
 
 41 4 1pq mC T T 
th
   
 
3 2 4 1
3 2
p p
th
p
mC T T mC T T
mC T T
  
 

4 1
3 2
1th
T T
T T

  

1
2 2
1 1
sT P
T P
 
 
  
 
1
2
1th
s
T
T
  
 
1
1
1th
pr
 

  

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7. Calculating the numerical indices by substituting the value of attributes and their relative importance in the permanent
function.
8. Document the results for future analysis/reference.
Based on the methodology discussed above, the organization can evaluate the extent of parameters present in GTPP.
Identification of performance parameters affecting thermal efficiency:
Through the literature review, it is found that a good amount of work was devoted in studying the effect of design
parameters on the performance of a gas turbine power plant. There are various performance parameters which affect the
thermal efficiency of GTPP. Some of the important parameters are:
(i) Inlet Air Temperature:
A gas turbine is a constant volume machine i.e. the volume of air compressed is fixed, irrespective of ambient air
temperature. Hence, as the temperature of inlet air to compressor rises, the density of air decreases and mass flow rate of
compressed air gets reduced. The power output of GTPP is proportional to mass flow rate of air. Thus, as the ambient
temperature increases, the power output decreases. Further, the thermal efficiency of the GTPP also falls, as more power
is required to compress warmer air. Thus, when the ambient temperature decreases the thermal efficiency increases and
vice versa.
Inlet air temperature affects other parameters of GTPP like -
 As inlet air temperature increases pressure ratio of compressor decreases or vice versa (acc. to equation 3.9).
 As inlet air temperature increases TIT of turbine decreases or vice-versa.
 As inlet air temperature increases isentropic compressor efficiency increases or vice versa (acc. to equation 3.2).
 As inlet air temperature increases isentropic turbine efficiency decreases or vice versa (acc. to equation 3.7).
(ii) Compression / pressure ratio:
In a gas turbine power plant, the intake air is initially compressed in the compressor to increase its pressure. Pressure ratio
is defined as the ratio of pressure after compression (P2) to the pressure before compression (P1). Pressure ratio is an
important parameter of GTPP. The thermal efficiency of GTPP increases with the increase of compression ratio [equation
11]. It affects the other parameters of GTPP like:
 Pressure ratio affects TIT as TIT = T3 = T4��𝑟𝑝
𝛾−1
𝛾
As pressure ratio increases TIT also increases and vice versa.
 The pressure ratio affects the compressor and turbine isentropic efficiencies, further explained in (acc. to equation 3.12
& equation 3.13).
 As pressure ratio increases isentropic compression efficiency decreases while isentropic turbine efficiency increases.
The reason behind the above statements is, during the compression process as defined by a polytropic path, there is an
increase in the inlet temperature to each compression stage due to irreversibility in the previous stage, thus resulting in
increased compression work [11].
However in turbines this increase in temperature will be recovered partly by expansion in next turbine stage and this
explains the different trends in isentropic efficiencies for the compressor and turbine [11].
(iii) Turbine inlet temperature (TIT) :
The limiting factor to the maximum power to weight ratio a gas turbine can reach is the metallurgical tolerance of the
alloys used in the hot section of the gas turbine. Ceramic coatings on the surfaces of the turbine airfoils can increase the
peak temperatures these airfoils can tolerate, however ceramics have brittleness characteristics that have not been totally

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overcome yet. So the “ruling parameter” is turbine inlet temperature (TIT). TIT in turn is a function of the turbine flame/
firing temperature, compression ratio, mass flow, and centrifugal stress. So these factors limit size and ultimately,
efficiency. A rough rule of thumb is that 55°C (100°F) increase in firing temperature gives a 10 to 13 percent power
output increase and a 2 to 4 percent efficiency increase. The combustion chambers and the turbine first stage stationary
nozzles and blades are therefore the most critical areas of the turbine that determine its power output and efficiency.
Highest TIT is decided by the metallurgical stress bearing capacity of turbine blade material. With the higher TIT larger is
the fuel consumption and work obtained in the cycle and cycle efficiency also increases. Thus, as the turbine inlet
temperature increases, power output and thermal efficiency increases [8]. In the present analysis, the effect of turbine inlet
temperature on other factors is not taken.
(iv) Isentropic compressor efficiency:
The efficiency of any machine, the object of which is the absorption or production of work, is normally expressed in
terms of the ratio of actual and ideal work transfers. Because turbo machinery are essentially adiabatic, the ideal process is
isentropic and the efficiency is called isentropic efficiency. Since isentropic efficiency considers only the start and end
states of the compression and expansion processes and pays no attention to the actual paths, the compression and
expansion processes take. Since work is not a property, it depends on the actual path.
Isentropic compressor efficiency is defined as the ratio of ideal compression work to the actual compression work [11].
i.e., 𝜼�C =
𝑖𝑑𝑒𝑎𝑙�𝑐𝑜𝑚𝑝𝑟𝑒𝑠𝑠𝑖𝑜𝑛�𝑤𝑜𝑟𝑘
𝑎𝑐𝑡𝑢𝑎𝑙�𝑐𝑜𝑚𝑝𝑟𝑒𝑠𝑠𝑖𝑜𝑛�𝑤𝑜𝑟𝑘
(5.1)
The isentropic compressor efficiency considers only the start and end state of compression process while polytropic
process considers the compression process in infinitesimally small steps. The value of isentropic compressor efficiency in
terms of polytropic efficiency is given by [11].
𝜼�C =
𝑟𝑝
𝛾−1
𝛾 �−1
𝑟𝑝
𝛾−1
η𝑝.𝛾−1
(5.2)
Where, 𝜼�p is the polytropic efficiency.
GT performance is affected by component efficiencies. The thermal efficiency increases with the increase of compressor
efficiency (acc. to equation 3.12).
(v) Isentropic turbine efficiency:
Isentropic efficiency is defined as the ratio of actual expansion work to ideal expansion work [11].
i.e., 𝜼�t =
𝑎𝑐𝑡𝑢𝑎𝑙�𝑒𝑥𝑝𝑎𝑛𝑠𝑖𝑜𝑛�𝑤𝑜𝑟𝑘
𝑖𝑑𝑒𝑎𝑙�𝑒𝑥𝑝𝑎𝑛𝑠𝑖𝑜𝑛�𝑤𝑜𝑟𝑘
The value of isentropic compressor efficiency in terms of polytropic efficiency is given by [11]
𝜼�t =
�1�−�
1
�𝑟𝑝
𝛾−1
𝛾
.ηp
�
1−�
1
𝑟𝑝
𝛾−1
𝛾
(5.3)
Where ηp is polytropic efficiency of turbine.
(vi) Air to Fuel Ratio (AFR):
Air to mass flow rate is defined as the ratio of air mass flow rate to the fuel mass flow rate i.e.,
AFR =
𝑚𝑎
𝑚𝑓
Where ma is mass flow rate (Kg/s) and mf is fuel mass flow rate (Kg/s)
From the literature survey [Rahman et al.] it is found that the thermal efficiency decreases with the increase in AFR and
vice versa. Also AFR affects the TIT (acc. to equation 3.6). As AFR increases TIT decreases and vice versa.

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Thus, the six performance parameters (effecting thermal efficiency of GTPP) taken for the present research work are:
(i) Inlet Air Temperature
(ii) Compression / pressure ratio
(iii) Turbine inlet temperature (TIT)
(iv) Isentropic compressor efficiency
(v) Isentropic turbine efficiency
(vi) Air to Fuel Ratio (AFR)
Table 5.3: Summary of maximum and minimum value of permanent function indices
Sr.no. Performance parameter Value of maximum VPF Value of minimum VPF
01 Inlet air temperature (IAT) 83160 9240
02 Compression pressure ratio (CR) 68250 9450
03 Turbine inlet temperature (TIT) 83160 9240
04 Isentropic compressor efficiency (𝜼C) 58800 8400
05 Isentropic compressor efficiency (𝜼t) 59400 6600
06 Air to fuel ratio (AFR) 69300 7700
9. RESULTS AND DISCUSSIONS
 Graph Theory and Matrix Method is a multi-attribute decision making method (MADM) which is successfully applied
on the roller burnishing process.
 By the application of Graph Theory and Matrix Method, we have identified the critical performance parameter
affecting the thermal efficiency of gas turbine power plant. In the present work, number of passes is the most critical
parameter having value of maximum variable permanent function = 85725.
 Graph Theory and Matrix Method is used in the selection of an improved process among various roller burnishing
processes by the comparison of variable permanent functions of the different processes.
 The Graph Theory and Matrix Method is used in the arrangement of the parameters according to their relative
importance in the process. The sequence of parameters in our work is number of passes, feed direction, workpiece
material, feed rate, coolant, burnishing speed.
 If some improvement is done in the parameters affecting the surface roughness of the process, then we can compare
the improved process with the previous process.
10. CONCLUSION & FUTURE SCOPE
Future Scope:
 Mathematical modeling may be done to find out the more inter-relations which would lead to the more accuracy in
the calculation of permanent function value.
 The roller burnishing process can be divided into different subgroups such as surface roughness, hardness, stress
value etc. and different values of permanent functions can be evaluated.
 Graph theoretic approach can be applied on various machining process.
 Complex manufacturing processes can be compared by the application of graph theoretic approach by comparing
their permanent function values.

ISSN 2393-8471
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Paper Publications
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