Dynamic Performance Simulation of an Aeroderivative Gas Turbine Using the Matlab Simulink Environment

Author(s):  
Elias Tsoutsanis ◽  
Nader Meskin ◽  
Mohieddine Benammar ◽  
Khashayar Khorasani

In fossil fuel applications, such as air transportation and power generation systems, gas turbine is the prime mover which governs the aircraft’s propulsive and the plant’s thermal efficiency, respectively. Therefore, an accurate engine performance simulation has a significant impact on the operation and maintenance of gas turbines as far as reliability and availability considerations are concerned. Current trends in achieving stable engine operation, reliable fault diagnosis and prognosis requirements do motivate the development and implementation of real-time dynamic simulators for gas turbines that are sufficiently complex, highly nonlinear, have high fidelity and include fast response modules. This paper presents a gas turbine performance model for predicting the transient dynamic behavior of an aeroderivative engine that is suitable for both mechanical drive and power generation applications. The engine model has been developed in the Matlab/Simulink environment and combines both the inter-component volume and the constant mass flow methods. Dynamic equations of the mass momentum and the energy balance are incorporated into the steady state thermodynamic equations. This allows one to represent the engine model by a set of first order differential and algebraic equations. The developed Simulink model in an object oriented environment, can be easily adapted to any kind of gas turbine configuration. The model consists of a number of subsystems for representing the gas turbine’s components and the thermodynamic relationships among them. The components are represented by a set of suitable performance maps that are available from the open literature. The engine model has been validated with an established gas turbine performance simulation software. Time responses of the main variables that describe the gas turbine dynamic behavior are also included. The proposed gas turbine model with its dynamic simulation characteristics is a useful tool for development of real-time model-based diagnostics and prognostics technologies.

2002 ◽  
Vol 128 (3) ◽  
pp. 506-517 ◽  
Author(s):  
S. M. Camporeale ◽  
B. Fortunato ◽  
M. Mastrovito

A high-fidelity real-time simulation code based on a lumped, nonlinear representation of gas turbine components is presented. The code is a general-purpose simulation software environment useful for setting up and testing control equipments. The mathematical model and the numerical procedure are specially developed in order to efficiently solve the set of algebraic and ordinary differential equations that describe the dynamic behavior of gas turbine engines. For high-fidelity purposes, the mathematical model takes into account the actual composition of the working gases and the variation of the specific heats with the temperature, including a stage-by-stage model of the air-cooled expansion. The paper presents the model and the adopted solver procedure. The code, developed in Matlab-Simulink using an object-oriented approach, is flexible and can be easily adapted to any kind of plant configuration. Simulation tests of the transients after load rejection have been carried out for a single-shaft heavy-duty gas turbine and a double-shaft aero-derivative industrial engine. Time plots of the main variables that describe the gas turbine dynamic behavior are shown and the results regarding the computational time per time step are discussed.


Author(s):  
Konstantinos G. Kyprianidis ◽  
Vishal Sethi ◽  
Stephen O. T. Ogaji ◽  
Pericles Pilidis ◽  
Riti Singh ◽  
...  

In this two-part publication, various aspects of thermo-fluid modelling for gas turbines are described and their impact on performance calculations and emissions predictions at aircraft system level is assessed. Accurate and reliable fluid modelling is essential for any gas turbine performance simulation software as it provides a robust foundation for building advanced multi-disciplinary modelling capabilities. Caloric properties for generic and semi-generic gas turbine performance simulation codes can be calculated at various levels of fidelity; selection of the fidelity level is dependent upon the objectives of the simulation and execution time constraints. However, rigorous fluid modelling may not necessarily improve performance simulation accuracy unless all modelling assumptions and sources of uncertainty are aligned to the same level. Certain modelling aspects such as the introduction of chemical kinetics, and dissociation effects, may reduce computational speed and this is of significant importance for radical space exploration and novel propulsion cycle assessment. This paper describes and compares fluid models, based on different levels of fidelity, which have been developed for an industry standard gas turbine performance simulation code and an environmental assessment tool for novel propulsion cycles. The latter comprises the following modules: engine performance, aircraft performance, emissions prediction, and environmental impact. The work presented aims to fill the current literature gap by: (i) investigating the common assumptions made in thermo-fluid modelling for gas turbines and their effect on caloric properties and (ii) assessing the impact of uncertainties on performance calculations and emissions predictions at aircraft system level. In Part I of this two-part publication, a comprehensive analysis of thermo-fluid modelling for gas turbines is presented and the fluid models developed are discussed in detail. Common technical models, used for calculating caloric properties, are compared while typical assumptions made in fluid modelling, and the uncertainties induced, are examined. Several analyses, which demonstrate the effects of composition, temperature and pressure on caloric properties of working mediums for gas turbines, are presented. The working mediums examined include dry air and combustion products for various fuels and H/C ratios. The errors induced by ignoring dissociation effects are also discussed.


Author(s):  
Konstantinos G. Kyprianidis ◽  
Vishal Sethi ◽  
Stephen O. T. Ogaji ◽  
Pericles Pilidis ◽  
Riti Singh ◽  
...  

In this two-part publication, various aspects of thermo-fluid modelling for gas turbines are described and their impact on performance calculations and emissions predictions at aircraft system level is assessed. Accurate and reliable fluid modelling is essential for any gas turbine performance simulation software as it provides a robust foundation for building advanced multi-disciplinary modelling capabilities. Caloric properties for generic and semi-generic gas turbine performance simulation codes can be calculated at various levels of fidelity; selection of the fidelity level is dependent upon the objectives of the simulation and execution time constraints. However, rigorous fluid modelling may not necessarily improve performance simulation accuracy unless all modelling assumptions and sources of uncertainty are aligned to the same level. Certain modelling aspects such as the introduction of chemical kinetics, and dissociation effects, may reduce computational speed and this is of significant importance for radical space exploration and novel propulsion cycle assessment. This paper describes and compares fluid models, based on different levels of fidelity, which have been developed for an industry standard gas turbine performance simulation code and an environmental assessment tool for novel propulsion cycles. The latter comprises the following modules: engine performance, aircraft performance, emissions prediction, and environmental impact. The work presented aims to fill the current literature gap by: (i) investigating the common assumptions made in thermo-fluid modelling for gas turbines and their effect on caloric properties and (ii) assessing the impact of uncertainties on performance calculations and emissions predictions at aircraft system level. In Part II of this two-part publication, the uncertainty induced in performance calculations by common technical models, used for calculating caloric properties, is discussed at engine level. The errors induced by ignoring dissociation are examined at 3 different levels: i) component level, ii) engine level, and iii) aircraft system level. Essentially, an attempt is made to shed light on the trade-off between improving the accuracy of a fluid model and the accuracy of a multi-disciplinary simulation at aircraft system level, against computational time penalties. The results obtained demonstrate that accurate modelling of the working fluid is not always essential; the accuracy/uncertainty for an overall engine model will always be better than the mean accuracy/uncertainty of the individual component estimates as long as systematic errors are carefully examined and reduced to acceptable levels to ensure error propagation does not cause significant discrepancies. Computational time penalties induced by improving the accuracy of the fluid model as well as the validity of the ideal gas assumption for future turbofan engines and novel propulsion cycles are discussed.


Author(s):  
K G Kyprianidis ◽  
V Sethi ◽  
S O T Ogaji ◽  
P Pilidis ◽  
R Singh ◽  
...  

In this article, various aspects of thermo-fluid modelling for gas turbines are described and the impact on performance calculations and emissions predictions at aircraft system level is assessed. Accurate and reliable fluid modelling is essential for any gas turbine performance simulation software as it provides a robust foundation for building advanced multi-disciplinary modelling capabilities. Caloric properties for generic and semi-generic gas turbine performance simulation codes can be calculated at various levels of fidelity; selection of the fidelity level is dependent upon the objectives of the simulation and execution time constraints. However, rigorous fluid modelling may not necessarily improve performance simulation accuracy unless all modelling assumptions and sources of uncertainty are aligned to the same level. A comprehensive analysis of thermo-fluid modelling for gas turbines is presented, and the fluid models developed are discussed in detail. Common technical models, used for calculating caloric properties, are compared while typical assumptions made in fluid modelling, and the uncertainties induced, are examined. Several analyses, which demonstrate the effects of composition, temperature, and pressure on caloric properties of working media for gas turbines, are presented. The working media examined include dry air and combustion products for various fuels and H/C ratios. The uncertainty induced in calculations by (a) using common technical models for evaluating fluid caloric properties and (b) ignoring dissociation effects is examined at three different levels: (i) component level, (ii) engine level, and (iii) aircraft system level. An attempt is made to shed light on the trade-off between improving the accuracy of a fluid model and the accuracy of a multi-disciplinary simulation at aircraft system level, against computational time penalties. The validity of the ideal gas assumption for future turbofan engines and novel propulsion cycles is discussed. The results obtained demonstrate that accurate modelling of the working fluid is essential, especially for assessing novel and/or aggressive cycles at aircraft system level. Where radical design space exploration is concerned, improving the accuracy of the fluid model will need to be carefully balanced with the computational time penalties involved.


Author(s):  
Vishal Sethi ◽  
Fulvio Diara ◽  
Sina Atabak ◽  
Anthony Jackson ◽  
Arjun Bala ◽  
...  

This paper describes the structure of an advanced fluid thermodynamic model which has been developed for a novel advanced gas turbine simulation environment called PROOSIS. PROOSIS (PRopulsion Object Oriented SImulation Software) is part of the VIVACE-ECP (Value Improvement through a Virtual Aeronautical Collaborative Enterprise - European Cycle Programme) project. The main objective of the paper is to determine a way to achieve an accurate, robust and reliable fluid model. The results obtained demonstrate that accurate modeling of the working fluid is essential to avoid convergence problems of the thermodynamic functions thereby increasing the accuracy of calculated fluid properties. Additionally, the impact of accurately modeling fuel thermodynamic properties, at the point of the injection, is discussed.


Author(s):  
Elias Tsoutsanis ◽  
Moussa Hamadache ◽  
Roger Dixon

Abstract Recent expansion of renewable power plants have transformed the role and operation of gas turbines to a great extent. From the base load operation era we are moving into a flexible and dynamic engine operation of gas turbines. In particular, aero derivative engines that have the capacity to start up, shut down in a short time frame are becoming quite popular for both hybrid power plant arrangements and distributed electricity generation. Advances in computational intelligence, such as digital twins, have amplified the importance of condition monitoring, diagnostics and prognostics capabilities in the face of gas turbine operation. Given the dynamic operating profile of the gas turbines, it is of paramount importance to develop, tune and deploy engine models that are accurate and robust to accommodate their nonlinear behavior. Performing diagnostics in transient conditions has recently gained attention, since the gas turbines are acting as partners of renewables and they have a supporting role. Among a family of diagnostics methods, one that has real time capabilities is based on zero-dimensional engine models. This paper present a novel diagnostic approach for determining the health of a gas turbine when it works in conjunction with a wind farm in hybrid power plant. In contrary to our earlier works, where we have mathematically modeled component maps to derive the health of an engine, in this paper we propose a model-based diagnostic method without reconstructing component maps according to their degradation. Once the engine model is initially adapted to its clean condition, it is subsequently tuned in real time to reflect the changes in both the operation and degradation with respect to a benchmark engine model. Time evolving multiple component degradation scenarios for a gas turbine operating in conjunction with a wind farm, are simulated to test the accuracy and efficiency of the proposed method. From a bank of simulated measurements, data trending is performed which facilitates the detection of degradation and provides useful conclusions about the health state of the engine. This diagnostic method is suitable for gas turbines that spend most of their life time in part-load and transient operation and it forms a simple and useful tool for operators in planning their assets maintenance in a computational efficient and accurate manner.


Author(s):  
V. Panov ◽  
S. Cruz-Manzo

Abstract This contribution reports on the development of Performance Digital Twin for industrial Small Gas Turbines. The objective of this study was the development of automation systems with control and monitoring functionalities, capable of addressing the requirements of future gas turbine plants for increased availability and reliability by use of Digital Twin technology. The project explored development of Performance Digital Twin based on Real-Time Embedded computing, which can be leveraged with Internet-of-Things (IOT) Cloud Platforms. The proposed solution was provided in a form of modular software for a range of hardware platforms, with corresponding functionalities to support advanced control, monitoring, tracking and diagnostics strategies. The developed Digital Twin was designed to be used in offline mode to assist the software commissioning process and in on-line mode to enable early detection of degradation and fault modes typical for gas path components. The Performance Digital Twin is based on a dynamic gas turbine model which was augmented with a Kalman tuner to enable performance tracking of physical assets. To support heterogeneity of gas turbine Distributed Control Systems (DCS), this project explored deployment of Digital Twin on multiple platforms. In the paper, we discuss model-based design techniques and tools specific for continuous, discrete and hybrid systems. The hybrid solution was deployed on PC-based platform and integrated with engine Distributed Control System in the field. Monitoring of gas turbine Performance Digital Twin functionalities has been established via Remote Monitoring System (STA-RMS). Assessment of deployed solution has been carried out and we present results from the field trial in this paper. The discrete solution was deployed on a range of Programable Logical Controller (PLC) platforms and has been tested by integrating Digital Twin in virtual engine Distributed Control System network. The Performance Digital Twin was embedded in Single Master PLC and Master-Slave PLC configurations, and we present results from the system testing using virtual gas turbine assets. The IoT Platform MindSphere was integrated within virtual engine network, and in this contribution, we explore expansion of the developed system with Cloud based applications and services.


Author(s):  
Rainer Kurz ◽  
Klaus Brun ◽  
Meron Wollie

This paper provides a discussion on how degradation develops and affects the performance of the gas turbine. Because the function of a gas turbine is the result of the fine tuned cooperation of many different components, the emphasis of this paper is on the gas turbine and its components as a system. Therefore, the interaction of components is studied in detail. An engine model is subjected to various types of degradation, and the effect on operating parameters is studied. The focus is on three areas: How does component degradation impact the operating points of the engine compressor, how does component degradation impact full load and part load gas turbine performance characteristics, and how does component degradation impact measurable engine operating parameters. Experimental data is provided that support the theoretical conclusion. Parameters that indicate levels of degradation are outlined, thus providing guidance for condition monitoring practice.


Author(s):  
Rainer Kurz ◽  
Klaus Brun ◽  
Meron Wollie

This paper provides a discussion on how degradation develops and affects the performance of the gas turbine. Because the function of a gas turbine is the result of the fine-tuned cooperation of many different components, the emphasis of this paper is on the gas turbine and its components as a system. Therefore, the interaction of components is studied in detail. An engine model is subjected to various types of degradation, and the effect on operating parameters is studied. The focus is on three areas: How does component degradation impact the operating points of the engine compressor, how does component degradation impact full load and part load gas turbine performance characteristics, and how does component degradation impact measurable engine operating parameters. Experimental data are provided that supports the theoretical conclusion. Parameters that indicate levels of degradation are outlined, thus providing guidance for condition monitoring practice.


Author(s):  
Siddig Dabbashi ◽  
Tarak Assaleh ◽  
Asia Gabassa

This paper investigates the effect of type and level of degradation in industrial gas turbine components on its performance under flexible operation due to working as a back-up to renewable energy sources (RES). This investigation was carried out for a 2-shaft 100MW aero-derivative gas turbine with intercooler. Due to the influence of unpredictable nature of power produced by RES, power plants are now operating in a flexible manner, which will require the operator to either stop operation during high feed-in from renewables or reducing the power output from the power plant to a certain percentage. This in turn has an impact on the gas turbine performance and thermal efficiency, which is also affected by the type and level of degradation of their components compared to the non-degraded gas turbines. In-House performance simulation software (TURBOMATCH), which was developed in Cranfield University, was used to carry out gas turbine performance modelling according to daily flexible operation scenarios for all seasons. These daily operating scenarios, which describe the power settings and ambient conditions for a period of 24 hours, were developed from data obtained from the UK national grid and the meteorology office data base. Different levels of degradation in mass flow and efficiency for low-pressure compressor and high-pressure turbine were applied in this study. Results illustrate an obvious impact of degradation type and level on fuel flow, turbine entry temperature, blade cooling temperature, shaft rotational speed and thermal efficiency for different seasons. This study has resulted in a tool which may be useful to power plant operators in understanding the various operating scenarios according to the criteria they wish to choose.


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