Modelling the Air-Cooled Gas Turbine: Part 1 — General Thermodynamics

2001 ◽  
Author(s):  
J. B. Young ◽  
R. C. Wilcock
Keyword(s):  
Gas Turbine ◽  
Performance Prediction ◽  
Real Gas ◽  
Thermal Mixing ◽  
Ideal Gases ◽  
Formal Framework ◽  
Considerable Simplification ◽  
Cycle Efficiency ◽  
General Thermodynamics

This paper is Part I of a study concerned with developing a formal framework for modelling air-cooled gas turbine cycles and deals with basic thermodynamic issues. Such cycles involve gas mixtures with varying composition which must be modelled realistically. A possible approach is to define just two components, air and gas, the latter being the products of stoichiometric combustion of the fuel with air. If these components can be represented as ideal gases, the entropy increase due to compositional mixing, although a true exergy loss, can be ignored for the purpose of performance prediction. This provides considerable simplification. Consideration of three idealised simple cycles shows that the introduction of cooling with an associated thermal mixing loss does not necessarily result in a loss of cycle efficiency. This is no longer true when real gas properties and turbomachinery losses are included. The analysis clarifies the role of the cooling losses and shows the importance of assessing performance in the context of the complete cycle. There is a strong case for representing the cooling losses in terms of irreversible entropy production as this provides a formalised framework, clarifies the modelling difficulties and aids physical interpretation. Results are presented which show the effects on performance of varying cooling flowrates and cooling losses. A comparison between simple and reheat cycles highlights the rôle of the thermal mixing loss. Detailed modelling of the heat transfer and cooling losses is discussed in Part II of this paper.

Modeling the Air-Cooled Gas Turbine: Part 1—General Thermodynamics

2002 ◽  
Vol 124 (2) ◽  
pp. 207-213 ◽  
Author(s):  
J. B. Young ◽  
R. C. Wilcock
Keyword(s):  
Gas Turbine ◽  
Performance Prediction ◽  
Real Gas ◽  
Thermal Mixing ◽  
Ideal Gases ◽  
Formal Framework ◽  
Considerable Simplification ◽  
Cycle Efficiency ◽  
General Thermodynamics

This paper is Part I of a study concerned with developing a formal framework for modeling air-cooled gas turbine cycles and deals with basic thermodynamic issues. Such cycles involve gas mixtures with varying composition which must be modeled realistically. A possible approach is to define just two components, air and gas, the latter being the products of stoichiometric combustion of the fuel with air. If these components can be represented as ideal gases, the entropy increase due to compositional mixing, although a true exergy loss, can be ignored for the purpose of performance prediction. This provides considerable simplification. Consideration of three idealized simple cycles shows that the introduction of cooling with an associated thermal mixing loss does not necessarily result in a loss of cycle efficiency. This is no longer true when real gas properties and turbomachinery losses are included. The analysis clarifies the role of the cooling losses and shows the importance of assessing performance in the context of the complete cycle. There is a strong case for representing the cooling losses in terms of irreversible entropy production as this provides a formalized framework, clarifies the modeling difficulties, and aids physical interpretation. Results are presented that show the effects on performance of varying cooling flowrates and cooling losses. A comparison between simple and reheat cycles highlights the ro^le of the thermal mixing loss. Detailed modeling of the heat transfer and cooling losses is discussed in Part II of this paper.

A New Superalloy Enabling Heavy Duty Gas Turbine Wheels for Improved Combined Cycle Efficiency

2017 ◽  
Author(s):  
Andrew Detor ◽  
◽  
Richard DiDomizio ◽  
Don McAllister ◽  
Erica Sampson ◽  
...  
Keyword(s):  
Gas Turbine ◽  
Combined Cycle ◽  
Heavy Duty ◽  
Heavy Duty Gas Turbine ◽  
Cycle Efficiency

Mixing of Exhaust and By-pass Flow in a By-pass Engine

1962 ◽  
Vol 66 (620) ◽  
pp. 528-530 ◽  
Author(s):  
H. Pearson
Keyword(s):  
Gas Turbine ◽  
Combustion Temperature ◽  
Propulsive Efficiency ◽  
Jet Engine ◽  
Equivalent Result ◽  
Jet Velocity ◽  
Cycle Efficiency

It is well known that the main purpose of the by-pass principle is to improve the propulsive efficiency of a simple jet engine by removing some of the energy left in the jet gases and using this to compress an extra quantity of air, known as the by-pass air, this air being ejected rearwards with the jet gases. In this way a greater mass of air is ejected rearwards at a lower jet velocity and thus a better propulsive efficiency is obtained. This is an extremely simplified view of the advantages of the by-pass engine, however, since an equivalent result of obtaining a lower jet velocity can be obtained by designing the jet engine for a lower combustion temperature. The by-pass principle is of advantage because it enables a higher propulsive efficiency to be obtained at the same time as employing a high combustion temperature and therefore a high basic cycle efficiency. If the component efficiencies of a gas turbine were 100 per cent, cycle efficiency would not depend upon combustion temperature at all, and there would thus be no advantage in principle in using the by-pass engine. In practice there would probably be some residual advantage left in that for a given thrust a lower engine weight could be obtained.

Thermal performance prediction of a solar hybrid gas turbine

Solar Energy ◽  
2012 ◽  
Vol 86 (7) ◽  
pp. 2116-2127 ◽  
Author(s):  
G. Barigozzi ◽  
G. Bonetti ◽  
G. Franchini ◽  
A. Perdichizzi ◽  
S. Ravelli
Keyword(s):  
Gas Turbine ◽  
Thermal Performance ◽  
Performance Prediction

scholarly journals Thermodynamic Analysis of Different Configurations of Combined Cycle Power Plants

2015 ◽  
Vol 5 (2) ◽  
pp. 89
Author(s):  
Munzer S. Y. Ebaid ◽  
Qusai Z. Al-hamdan
Keyword(s):  
Gas Turbine ◽  
Power Plants ◽  
Combined Cycle ◽  
Cycle Performance ◽  
Maximum Efficiency ◽  
Specific Work ◽  
Slight Effect ◽  
Turbine Engine ◽  
Gas Turbine Cycle ◽  
Cycle Efficiency

<p class="1Body">Several modifications have been made to the simple gas turbine cycle in order to increase its thermal efficiency but within the thermal and mechanical stress constrain, the efficiency still ranges between 38 and 42%. The concept of using combined cycle power or CPP plant would be more attractive in hot countries than the combined heat and power or CHP plant. The current work deals with the performance of different configurations of the gas turbine engine operating as a part of the combined cycle power plant. The results showed that the maximum CPP cycle efficiency would be at a point for which the gas turbine cycle would have neither its maximum efficiency nor its maximum specific work output. It has been shown that supplementary heating or gas turbine reheating would decrease the CPP cycle efficiency; hence, it could only be justified at low gas turbine inlet temperatures. Also it has been shown that although gas turbine intercooling would enhance the performance of the gas turbine cycle, it would have only a slight effect on the CPP cycle performance.</p>

Hybrid Modeling of Heavy Duty Gas Turbines for On-Line Performance Monitoring

2014 ◽  
Author(s):  
Thomas Palmé ◽  
Francois Liard ◽  
Dan Cameron
Keyword(s):  
Gas Turbine ◽  
Surrogate Model ◽  
Gas Turbines ◽  
Performance Monitoring ◽  
Performance Model ◽  
Heavy Duty ◽  
Operational Parameters ◽  
Actual Performance ◽  
Real Gas ◽  
The Real

Due to their complex physics, accurate modeling of modern heavy duty gas turbines can be both challenging and time consuming. For online performance monitoring, the purpose of modeling is to predict operational parameters to assess the current performance and identify any possible deviation between the model’s expected performance parameters and the actual performance. In this paper, a method is presented to tune a physical model to a specific gas turbine by applying a data-driven approach to correct for the differences between the real gas turbine operation and the performance model prediction of the same. The first step in this process is to generate a surrogate model of the 1st principle performance model through the use of a neural network. A second “correction model” is then developed from selected operational data to correct the differences between the surrogate model and the real gas turbine. This corrects for the inaccuracies between the performance model and the real operation. The methodology is described and the results from its application to a heavy duty gas turbine are presented in this paper.

The Impact of Gas Modeling in the Numerical Analysis of a Multistage Gas Turbine

2008 ◽  
Vol 130 (2) ◽  
Author(s):  
Filippo Rubechini ◽  
Michele Marconcini ◽  
Andrea Arnone ◽  
Massimiliano Maritano ◽  
Stefano Cecchi
Keyword(s):  
Gas Turbine ◽  
Flow Direction ◽  
Three Dimensional ◽  
Navier Stokes ◽  
Ratio Distribution ◽  
Real Gas ◽  
Turbine Performance ◽  
Wall Boundary Conditions ◽  
Heavy Duty Gas Turbine ◽  
The Impact

In this work a numerical investigation of a four stage heavy-duty gas turbine is presented. Fully three-dimensional, multistage, Navier-Stokes analyses are carried out to predict the overall turbine performance. Coolant injections, cavity purge flows, and leakage flows are included in the turbine modeling by means of suitable wall boundary conditions. The main objective is the evaluation of the impact of gas modeling on the prediction of the stage and turbine performance parameters. To this end, four different gas models were used: three models are based on the perfect gas assumption with different values of constant cp, and the fourth is a real gas model which accounts for thermodynamic gas properties variations with temperature and mean fuel∕air ratio distribution in the through-flow direction. For the real gas computations, a numerical model is used which is based on the use of gas property tables, and exploits a local fitting of gas data to compute thermodynamic properties. Experimental measurements are available for comparison purposes in terms of static pressure values at the inlet∕outlet of each row and total temperature at the turbine exit.

scholarly journals Modeling of advanced fossil fuel power plants

2021 ◽  
Author(s):  
Farshid Zabihian
Keyword(s):  
Power Generation ◽  
Gas Turbine ◽  
Power Plants ◽  
Fossil Fuel ◽  
Specific Power ◽  
Operating Pressure ◽  
Utilization Factor ◽  
Fuel Switching ◽  
Wide Range ◽  
Cycle Efficiency

The first part of this thesis deals with greenhouse gas (GHG) emissions from fossil fuel-fired power stations. The GHG emission estimation from fossil fuel power generation industry signifies that emissions from this industry can be significantly reduced by fuel switching and adaption of advanced power generation technologies. In the second part of the thesis, steady-state models of some of the advanced fossil fuel power generation technologies are presented. The impacts of various parameters on the solid oxide fuel cell (SOFC) overpotentials and outputs are investigated. The detail analyses of operation of the hybrid SOFC-gas turbine (GT) cycle when fuelled with methane and syngas demonstrate that the efficiencies of the cycles with and without anode exhaust recirculation are close, but the specific power of the former is much higher. The parametric analysis of the performance of the hybrid SOFC-GT cycle indicates that increasing the system operating pressure and SOFC operating temperature and fuel utilization factor improves cycle efficiency, but the effects of the increasing SOFC current density and turbine inlet temperature are not favourable. The analysis of the operation of the system when fuelled with a wide range of fuel types demonstrates that the hybrid SOFC-GT cycle efficiency can be between 59% and 75%, depending on the inlet fuel type. Then, the system performance is investigated when methane as a reference fuel is replaced with various species that can be found in the fuel, i.e., H₂, CO₂, CO, and N₂. The results point out that influence of various species can be significant and different for each case. The experimental and numerical analyses of a biodiesel fuelled micro gas turbine indicate that fuel switching from petrodiesel to biodiesel can influence operational parameters of the system. The modeling results of gas turbine-based power plants signify that relatively simple models can predict plant performance with acceptable accuracy. The unique feature of these models is that they are developed based on similar assumptions and run at similar conditions; therefore, their results can be compared. This work demonstrates that, although utilization of fossil fuels for power generation is inevitable, at least in the short- and mid-term future, it is possible and practical to carry out such utilization more efficiently and in an environmentally friendlier manner.

scholarly journals The role of Islamic Educational Institutions in Achieving Intellectual Unity among Muslims in Cameroon: دور المؤسسات التربوية الإسلامية في تحقيق الوحدة الفكرية بين المسلمين في الكاميرون

2020 ◽  
Vol 4 (12) ◽  
Author(s):  
Mouhamadou Maudud
Keyword(s):  
Human Life ◽  
Functional Integration ◽  
Educational Institutions ◽  
Educational Work ◽  
Academic Challenges ◽  
Formal Framework ◽  
Cultural Cohesion ◽  
Intellectual Unity ◽  
The Relationship

Unity is one of the fundamental tools for social security in human life and Islamic Educational institutions in Cameroon are not excluded. The present study aimed at identifying the main roles and Educational needs of Islamic Educational institutions in Cameroon in bringing about Intellectual unity. The descriptive analytical approach was used as a research methodology. The research has come up with the following findings: The spread of misconceptions among individuals is the main cause of weak and limited results of educational work. Due to this, the relationship between those institutions and the society in its formal framework remains negative. The Islamic Educational institutions in Cameroon have been playing an important role in the service of religion and society in order to preserve peace and unity, but despite its tangible achievements they still face challenges in some aspect, such as academic challenges, scientific developments, and Educational supervision, which were identified as obstacle to functional integration. In conclusion, it is recommended to develop a strategic and effective programs in which all the Islamic Educational institutions of Cameroon are involved in order to erase the misconceptions causing intellectual disunity. These should involve dissemination of pure Islamic values, modern technical and professional educational courses, besides promoting solidarity, religious and cultural cohesion in order to address the diverse challenges of the enemies of religion and society.

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