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1
Thompson, Haydn Ashley. "Parallel processing applications for gas turbine engine control." Thesis, Bangor University, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.254683.
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2
Churchhouse, Stephen Paul. "Multivariable control of a propfan engine." Thesis, University of Cambridge, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.303222.
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3
Keng, W. "Gas turbine engine control and performance enhancement with fuzzy logic." Thesis, Cranfield University, 1998. http://dspace.lib.cranfield.ac.uk/handle/1826/11028.
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Gas turbine engine performance improvement has been requested continuously for both military and commercial applications due t various reasons. One of the issues is to save fuel and/or to increase the engine life to meet the multi-mission and operation cost economics requirements. I order to satisfy the customers' requirements, the engine manufacturers invested a lot of money and time if the gas turbine performance improvement. The most straight forward and simple approach is to trade the excess remained surge margins for performance. NASA has demonstrated the feasibility of this concept in their F-15 Highly Integrated Digital Electronic Control and Performance Seeking Control programs. It offers not only obvious benefits if the overall system performance improvement but also cost effective operations such a fuel saving and extended component life. Those were carried out with traditional control approaches which have to face the modelling difficulties. ' Due to successful control implementations of fuzzy logic if various environment of uncertainties, a proportional plus integral z logic controller if proposed. The fuzzy logic control system simulation results prove that the fuzzy logic controller is appropriate for gas turbine engine control. Basic fuzzy logic control concept is used with new approaches to simplifying the fuzzy logic controller. I order to enhance the engine performance, fuzzy logic control concept is used to optimize the engine performance parameters. A time function linear control scheme is proposed to the engine to a new operation location System simulation results prove the new methodology. It has to be understood that the engine model used if this research is not representative of a gas turbine, but it `is appropriate for the fuzzy logic control design analysis and simulation.
4
Mahmoud, Saad M. "Effective optimal control of a fighter aircraft engine." Thesis, Loughborough University, 1988. https://dspace.lboro.ac.uk/2134/7287.
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Typical modem fighter aircraft use two-spool, low by-pass ratio, turbojet engines to provide the thrust needed to carry out the combat manoeuvres required by present-day air warfare tactics. The dynamic characteristics of such aircraft engines are complex and non-linear. The need for fast, accurate control of the engine throughout the flight envelope is of paramount importance and this research was concerned with the study of such problems and subsequent design of an optimal linear control which would improve the engine's dynamic response and provide the required correspondence between the output from the engine and the values commanded by a pilot. A detailed mathematical model was derived which, in accuracy and complexity of representation, was a large improvement upon existing analytical models, which assume linear operation over a very small region of the state space, and which was simpler than the large non-analytic representations, which are based on matching operational data. The non-linear model used in this work was based upon information obtained from DYNGEN, a computer program which is used to calculate the steady-state and transient responses of turbojet and turbofan engines. It is a model of fifth order which, it is shown, correctly models the qualitative behaviour of a representative jet engine. A number of operating points were selected to define the boundaries used for the flight envelope. For each point a performance investigation was carried out and a related linear model was established. By posing the problem of engine control as a linear quadratic problem, in which the constraint was the state equation of the linear model, control laws appropriate for each operating point were obtained. A single control was effective with the linear model at every point. The same control laws were then applied to the non-linear mathematical model adjusted for each operating point, and the resulting responses were carefully studied to determine if one single control law could be used with all operating points. Such a law was established. This led, naturally, to the determination of an optimal linear tracking control law, and a further investigation to determine whether there existed an optimal non-linear control law for the non-linear model. In the work presented in this dissertation these points are fully discussed and the reasons for choosing to find an optimal linear control law for the non-linear model by solving the related two-point, boundary value problem using the method of quasilinearisation are presented. A comparison of the effectiveness of the respective optimal control laws, based upon digital simulation, is made before suggestions and recommendations for further work are presented.
5
Gomma, Hesham Wagih. "Robust and predictive control of 1.5 MW gas turbine engine." Thesis, University of Exeter, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.302533.
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Keng, W. "Gas turbine engine control and performance enchancement with fuzzy logic." Thesis, Cranfield University, 1998. http://dspace.lib.cranfield.ac.uk/handle/1826/11028.
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Gas turbine engine performance improvement has been requested continuously for both
military and commercial applications due t various reasons. One of the issues is to save
fuel and/or to increase the engine life to meet the multi-mission and operation cost
economics
requirements. I order to satisfy the customers' requirements, the engine
manufacturers invested a lot of money and time if the gas turbine performance
improvement. The most straight forward and simple approach is to trade the excess
remained
surge margins for performance. NASA has demonstrated the feasibility of this
concept in their F-15 Highly Integrated Digital Electronic Control and Performance
Seeking Control programs. It offers not only obvious benefits if the overall system
performance improvement but also cost effective operations such a fuel saving and
extended component life. Those were carried out with traditional control approaches
which have to face the modelling difficulties. ' Due to successful control
implementations of fuzzy logic if various environment of uncertainties, a proportional
plus integral z logic controller if proposed. The fuzzy logic control system
simulation results prove that the fuzzy logic controller is appropriate for gas turbine
engine control. Basic fuzzy logic control concept is used with new approaches to
simplifying the fuzzy logic controller. I order to enhance the engine performance, fuzzy
logic control concept is used to optimize the engine performance parameters. A time
function linear control scheme is proposed to the engine to a new operation location
System simulation results prove the new methodology. It has to be understood that the
engine model used if this research is not representative of a gas turbine, but it `is
appropriate for the fuzzy logic control design analysis and simulation.
7
Chung, Gi Yun. "An analytical approach to real-time linearization of a gas turbine engine model." Diss., Georgia Institute of Technology, 2013. http://hdl.handle.net/1853/50702.
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A recent development in the design of control system for a jet engine is to use a suitable, fast and accurate model running on board. Development of linear models is particularly important as most engine control designs are based on linear control theory. Engine control performance can be significantly improved by increasing the accuracy of the developed model. Current state-of-the-art is to use piecewise linear models at selected equilibrium conditions for the development of set point controllers, followed by scheduling of resulting controller gains as a function of one or more of the system states. However, arriving at an effective gain scheduler that can accommodate fast transients covering a wide range of operating points can become quite complex and involved, thus resulting in a sacrifice on controller performance for its simplicity.
This thesis presents a methodology for developing a control oriented analytical linear model of a jet engine at both equilibrium and off-equilibrium conditions. This scheme requires a nonlinear engine model to run onboard in real time. The off-equilibrium analytical linear model provides improved accuracy and flexibility over the commonly used piecewise linear models developed using numerical perturbations. Linear coefficients are obtained by evaluating, at current conditions, analytical expressions which result from differentiation of simplified nonlinear expressions. Residualization of the fast dynamics states are utilized since the fast dynamics are typically outside of the primary control bandwidth. Analytical expressions based on the physics of the aerothermodynamic processes of a gas turbine engine facilitate a systematic approach to the analysis and synthesis of model based controllers. In addition, the use of analytical expressions reduces the computational effort, enabling linearization in real time at both equilibrium and off-equilibrium conditions for a more accurate capture of system dynamics during aggressive transient maneuvers.
The methodology is formulated and applied to a separate flow twin-spool turbofan engine model in the Numerical Propulsion System Simulation (NPSS) platform. The fidelity of linear model is examined by validating against a detailed nonlinear engine model using time domain response, the normalized additive uncertainty and the nu-gap metric. The effects of each simplifying assumptions, which are crucial to the linear model development, on the fidelity of the linear model are analyzed in detail. A case study is performed to investigate the case when the current state (including both slow and fast states) of the system is not readily available from the nonlinear simulation model. Also, a simple model based control is used to illustrate benefits of using the proposed modeling approach.
8
Stambaugh, Craig T. (Craig Todd) 1960. "Improving gas turbine engine control system component optimization by delaying decisions." Thesis, Massachusetts Institute of Technology, 2003. http://hdl.handle.net/1721.1/91787.
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Bae, Jinwoo W. "An experimental study of surge control in a helicopter gas turbine engine." Thesis, Massachusetts Institute of Technology, 1998. http://hdl.handle.net/1721.1/50319.
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Villarreal, Daniel Christopher. "Digital Fuel Control for a Lean Premixed Hydrogen-Fueled Gas Turbine Engine." Thesis, Virginia Tech, 2009. http://hdl.handle.net/10919/34974.
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Hydrogen-powered engines have been gaining increasing interest due to the global concerns of
the effects of hydrocarbon combustion on climate change. Gas turbines are suitable for operation on hydrogen fuel. This thesis reports the results of investigations of the special requirements of the fuel controller for a hydrogen gas turbine. In this investigation, a digital fuel controller for a hydrogen-fueled modified Pratt and Whitney PT6A-20 turboprop engine was successfully designed and implemented. Included in the design are safety measures to protect the operating personnel and the engine. A redundant fuel control is part of the final design to provide a second method of managing the engine should there be a malfunction in any part of the primary controller.
<p>
Parallel to this study, an investigation of the existing hydrogen combustor design was performed to analyze the upper stability limits that were restricting the operability of the engine. The upstream propagation of the flame into the premixer, more commonly known as a flashback, routinely occurred at 150 shaft horsepower during engine testing. The procedures for protecting the engine from a flashback were automated within the fuel controller, significantly reducing the response time from the previous (manual) method. Additionally, protection measures were added to ensure the inter-turbine temperature of the engine did not exceed published limits. Automatic engine starting and shutdown procedures were also added to the control logic, minimizing the effort needed by the operator. The tested performance of the engine with each of the control functions demonstrated the capability of the controller.
<p>
Methods to generate an engine-specific fuel control map were also studied. The control map would not only takes into account the operability limits of the engine, but also the stability limits of the premixing devices. Such a map is integral in the complete design of the engine fuel
controller.<br>Master of Science
11
Pakmehr, Mehrdad. "Towards verifiable adaptive control of gas turbine engines." Diss., Georgia Institute of Technology, 2013. http://hdl.handle.net/1853/49025.
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This dissertation investigates the problem of developing verifiable stable control architectures for gas turbine engines. First, a nonlinear physics-based dynamic model of a twin spool turboshaft engine which drives a variable pitch propeller is developed. In this model, the dynamics of the engine are defined to be the two spool speeds, and the two control inputs to the system are fuel flow rate and prop pitch angle. Experimental results are used to verify the dynamic model of JetCat SPT5 turboshaft engine. Based on the experimental data, performance maps of the engine components including propeller, high pressure compressor, high pressure, and low pressure turbines are constructed. The engine numerical model is implemented using Matlab.
Second, a stable gain scheduled controller is described and developed for a gas turbine engine that drives a variable pitch propeller. A stability proof is developed for a gain scheduled closed-loop system using global linearization and linear matrix inequality (LMI) techniques. Using convex optimization tools, a single quadratic Lyapunov function is computed for multiple linearizations near equilibrium and non-equilibrium points of the nonlinear closed-loop system. This approach guarantees stability of the closed-loop gas turbine engine system. To verify the stability of the closed-loop system on-line, an optimization problem is proposed which is solvable using convex optimization tools. Through simulations, we show the developed gain scheduled controller is capable to regulate a turboshaft engine for large thrust commands in a stable fashion with proper tracking performance.
Third, a gain scheduled model reference adaptive control (GS-MRAC) concept for multi-input multi-output (MIMO) nonlinear plants with constraints on the control inputs is developed and described. Specifically, adaptive state feedback for the output tracking control problem of MIMO nonlinear systems is studied. Gain scheduled reference model system is used for generating desired state trajectories, and the stability of this reference model is also analyzed using convex optimization tools. This approach guarantees stability of the closed-loop gain scheduled gas turbine engine system, which is used as a gain scheduled reference model. An adaptive state feedback control scheme is developed and its stability is proven, in addition to transient and steady-state performance guarantees. The resulting closed-loop system is shown to have ultimately bounded solutions with a priori adjustable bounded tracking error. The results are then extended to GS-MRAC with constraints on the magnitudes of multiple control inputs. Sufficient conditions for uniform boundedness of the closed-loop system is derived. A semi-global stability result is proven with respect to the level of saturation for open-loop unstable plants, while the stability result is shown to be global for open-loop stable plants. Simulations are performed for three different models of the turboshaft engine, including the nominal engine model and two models where the engine is degraded. Through simulations, we show the developed GS-MRAC architecture can be used for the tracking problem of degraded turboshaft engine for large thrust commands with guaranteed stability.
Finally, a decentralized linear parameter dependent representation of the engine model is developed, suitable for decentralized control of the engine with core and fan/prop subsystems. Control theoretic concepts for decentralized gain scheduled model reference adaptive control (D-GS-MRAC) systems is developed. For each subsystem, a linear parameter dependent model is available and a common Lyapunov matrix can be computed using convex optimization tools. With this control architecture, the two subsystems of the engine (i.e., engine core and engine prop/fan) can be controlled with independent controllers for large throttle commands in a decentralized manner. Based on this D-GS-MRAC architecture, a "plug and play" (PnP) technology concept for gas turbine engine control systems is investigated, which allows us to match different engine cores with different engine fans/propellers. With this plug and play engine control architecture, engine cores and fans/props could be used with their on-board subordinate controllers ready for integration into a functional propulsion system. Simulation results for three different models of the engine, including the nominal engine model, the model with a new prop, and the model with a new engine core, illustrate the possibility of PnP technology development for gas turbine engine control systems.
12
Sheldon, Karl Edward. "Analysis Methods to Control Performance Variability and Costs in Turbine Engine Manufacturing." Thesis, Virginia Tech, 2001. http://hdl.handle.net/10919/32290.
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Few aircraft engine manufacturers are able to consistently achieve high levels of performance reliability in newly manufactured engines. Much of the variation in performance reliability is due to the combined effect of tolerances of key engine components, including tip clearances of rotating components and flow areas in turbine nozzles. This research presents system analysis methods for determining the maximum possible tolerances of these key components that will allow a turbine engine to pass a number of specified performance constraints at a selected level of reliability.
Through the combined use of a state-of-the-art engine performance code, component clearance loss models, and stochastic simulations, regions of feasible design space can be explored that allow for a pre-determined level of engine reliability. As expected, constraints such as spool speed and fuel consumption that are highly sensitive to certain component tolerances can significantly limit the feasible design space of the component in question. Discussed are methods for determining the bounds of any components feasible design space and for selecting the most economical combinations of component tolerances.
Unique to this research is the method that determines the tolerances of engine components as a system while maintaining the geometric constraints of individual components. The methods presented in this work allow for any number of component tolerances to be varied or held fixed while providing solutions that satisfy all performance criteria. The algorithms presented in this research also allow for an individual specification of reliability on any number of performance parameters and geometric constraints.
This work also serves as a foundation for an even larger algorithm that can include stochastic simulations and reliability prediction of an engine over its entire life cycle. By incorporating information such as time dependent performance data, known mission profiles, and the influence of maintenance into the component models, it would be possible to predict the reliability of an engine over time. Ultimately, a time-variant simulation such as this could help predict the timing and levels of maintenance that will maximize the life of an engine for a minimum cost.<br>Master of Science
13
Haas, David William. "The instrumentation design and control of a T63-A-700 gas turbine engine." Thesis, Monterey, California. Naval Postgraduate School, 1996. http://hdl.handle.net/10945/8538.
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Approved for public release; distribution is unlimited<br>Gas Turbine Instrumentation and Control<br>A T63-A-700 gas turbine engine has been instrumented to measure performance parameters. Pressure and temperature monitoring systems have been designed, fabricated, and installed to ensure accurate measurement of performance parameters. All measured parameters have been compared against predicted thermodynamic cycle analysis. Design and control of selected engine systems have been modified to incorporate more precise engine control and safety
14
McNulty, Gregory Scott. "A study of dynamic compressor surge control strategies for a gas turbine engine." Thesis, Massachusetts Institute of Technology, 1993. http://hdl.handle.net/1721.1/47350.
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Wang, Chen. "Transient performance simulation of gas turbine engine integrated with fuel and control systems." Thesis, Cranfield University, 2016. http://dspace.lib.cranfield.ac.uk/handle/1826/9881.
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Two new methods for the simulation of gas turbine fuel systems, one based on an inter-component volume (ICV) method, and the other based on the iterative Newton Raphson (NR) method, have been developed in this study. They are able to simulate the performance behaviour of each of the hydraulic components such as pumps, valves, metering unit of a fuel system, using physics-based models, which potentially offer more accurate results compared with those using transfer functions. A transient performance simulation system has been set up for gas turbine engines based on an inter-component volume (ICV). A proportional- integral (PI) control strategy is used for the simulation of engine control systems. An integrated engine and its control and hydraulic fuel systems has been set up to investigate their coupling effect during engine transient processes. The developed simulation methods and the systems have been applied to a model turbojet and a model turboshaft gas turbine engine to demonstrate the effectiveness of both two methods. The comparison between the results of engines with and without the ICV method simulated fuel system models shows that the delay of the engine transient response due to the inclusion of the fuel system components and introduced inter-component volumes is noticeable, although relatively small. The comparison of two developed methods applied to engine fuel system simulation demonstrate that both methods introduce delay effect to the engine transient response but the NR method is ahead than the ICV method due to the omission of inter-component volumes on engine fuel system simulation. The developed simulation methods are generic and can be applied to the performance simulation of any other gas turbines and their control and fuel systems. A sensitivity analysis of fuel system key parameters that may affect the engine transient behaviours has also been achieved and represented in this thesis. Three sets of fuel system key parameters have been introduced to investigate their sensitivities, which are, the volumes introduced for ICV method applied to fuel system simulation; the time constants introduced into those first order lags tosimulate the valve movements delay and fuel spray delay effect; and the fuel system key performance and structural parameters.
16
Kamalova, Zukhra. "Dynamic modelling and control of gas turbine engines." Thesis, University of Manchester, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.492127.
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This work is focused on the investigation of the performance of genetic algorithms with application to on-line dynamic modelling of a gas turbine engine. Data from a real engine is used to create, compare and analyse genetic algorithms. The gas turbine engine models obtained from the engine input-output data using genetic algorithm have been used in a Local Optimal Control design. An analogy between the first order Local Optimal Controller and the PI controller parameters has been discovered. An approach for tuning the PI controller parameters using Local Optimal Controller is presented.
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Korak, Ghosh. "Model predictive control for civil aerospace gas turbine engines." Thesis, University of Sheffield, 2013. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.595827.
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Afshari, Seyed Saeed Tavakoli. "Multivariable PID control with application to gas turbine engines." Thesis, University of Sheffield, 2006. http://etheses.whiterose.ac.uk/14882/.
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To meet increasing and often conflicting demands on performance, stability, fuel consumption and functionality, modem jet engines are becoming increasingly complex. Improved compressor performance is a major factor in this development process. Optimum compressor efficiency is achieved in operating regions close to flow instability. Surveying basic concepts and control methods of compressor instabilities, an overview of the fundamentals of surge and rotating stall is presented. To maximise the potential of an aero gas turbine compression system, it is proposed to use more advanced control strategies, such as multi variable control. Multivariable control may offer the prospect of lower safety margin requirements leading to greater compressor efficiency. Alternatively, it may result in more agility in combat through improved engine responses and prolonged engine life. A multivariable control technique is proposed and tested on a Rolls-Royce three-spool high bypass ratio turbofan engine. Since elements of the 2x2 system can be represented by linear third order models, a muItivariable PID controller will be sufficient provided the design requirements are not too rigorous. To have a simple and efficient design, a systematic decentralised PI (PID) control design strategy is developed. Decoupling a given 2x2 process by a stable decoupler, the elements of the resulting diagonal matrix are approximated by first (second) order plus dead time processes using the proposed model reduction techniques. Then, SISO controllers are designed for each element using the developed tuning formulae. Any practical design method should be simple, easy to apply, flexible, generic or extendable, and applicable to complex control schemes to fulfil more demanding control requirements. It will be advantageous if the design algorithm can also directly address the design requirements, be repeatable for any control objective, constraint and category of processes, have a design parameter, and can consider any number of objectives and constraints. Formulating the PI (PID) control design problem as an optimisation problem, a non-dimensional tuning (NDT) method satisfying the above-mentioned design properties is presented. For a given first (second) order plus dead time process, the NOT method is used in conjunction with either a single-objective or a multi-objective optimisation approach to design PI (PID) controllers satisfying conflicting design requirements. In addition, considering load disturbance rejection as the primary design objective, a simple analytical PI tuning method is presented. The design problem is constrained with a specified gain or phase margin. Compared to the corresponding conventional SISO controller, it is demonstrated that the resulting decentralised controller considerably improves the overall surge risk to the engine during the transient manoeuvres while maintaining similar thrust levels. Due to non-linearity of jet engine models, gain scheduling is necessary. Designing decentralised controllers at various operating points, the gain-scheduled controller accommodates the non-linearity in engine dynamics over the full thrust range.
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Prashanth, Prakash. "Post-combustion emissions control for aero-gas turbine engines." Thesis, Massachusetts Institute of Technology, 2018. https://hdl.handle.net/1721.1/122402.
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Thesis: S.M., Massachusetts Institute of Technology, Department of Aeronautics and Astronautics, 2018<br>Cataloged from PDF version of thesis.<br>Includes bibliographical references (pages 47-50).<br>Aviation NO[subscript x] emissions have an impact on air quality and climate change, where the latter is magnified due to the higher sensitivity of the upper troposphere and lower stratosphere. In the aviation industry, efforts to increase the efficiency of propulsion systems are giving rise to higher overall pressure ratios which results in higher NO[subscript x] emissions due to increased combustion temperatures. This thesis identifies that the trend towards smaller engine cores (gas generators) that are power dense and contribute little to the thrust output presents new opportunities for emissions control that were previously unthinkable when the core exhaust stream contributed significant thrust. This thesis proposes and assesses selective catalytic reduction (SCR), which is a post-combustion emissions control method used in ground-based sources such as power generation and heavy-duty diesel engines, for use in aero-gas turbines.<br>The SCR system increases aircraft weight and introduces a pressure drop in the core stream. The effects of these are evaluated using representative engine cycle models provided by a major aero-gas turbine manufacturer. This thesis finds that employing an ammonia-based SCR can achieve close to 95% reduction in NO[subscript x] emissions for ~0.4% increase in block fuel burn. The large size of the catalyst needs to be housed in the body of the aircraft and hence would be suitable for future designs where the engine core is also within the fuselage, such as would be possible with turbo-electric or hybrid-electric designs. The performance of the post-combustion emissions control is shown to improve for smaller core engines in new aircraft in the NASA N+3 time-line (2030-2035), suggesting the potential to further decrease the cost of the ~95% NO[subscript x] reduction to below ~0.4% fuel burn.<br>Using a global chemistry and transport model (GEOS-Chem) this thesis estimates that using ultra-low sulfur (<15 ppm fuel sulfur content) in tandem with post-combustion emissions control results in a ~92% reduction in annual average population exposure to PM₂.₅ and a ~95% reduction in population exposure to ozone. This averts approximately 93% of the air pollution impact of aviation.<br>by Prakash Prashanth.<br>S.M.<br>S.M. Massachusetts Institute of Technology, Department of Aeronautics and Astronautics
20
Ekong, Godwin I. "Tip clearance control concepts in gas turbine H.P. compressors." Thesis, University of Sussex, 2014. http://sro.sussex.ac.uk/id/eprint/48906/.
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Egener, P. "Design, implementation, and testing of a digital control system for a small gas turbine engine." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape8/PQDD_0006/MQ44840.pdf.
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Lyes, Peter A. "Low speed axial compressor design and evaluation : High speed representation and endwall flow control studies." Thesis, Cranfield University, 1999. http://hdl.handle.net/1826/4251.
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This Thesis reports the design, build and test of two sets of blading for the
Cranfield University low speed research compressor. The first of these was a datum low
speed design based on the fourth stage of the DERA high speed research compressor
C 147. The emphasis of this datum design was on the high-to-low speed transformation
process and the evaluation of such a process through comparing detailed flow
measurements from both compressors.
Area traverse measurements in both the stationary and rotating frame of reference
were taken at Cranfield along with overall performance, blade surface static pressure and
flow visualisation measurements. These compare favourably with traverse and
performance measurements taken on C147 before commencement of the PhD work.
They show that despite the compromises made during the transformation process, due to
both geometric and aerodynamic considerations, both the primary and secondary flow
features can be successfully reproduced in the low speed environment.
The aim of the second design was to improve on the performance of the datum
blading through the use of advanced '3D' design concepts such as lean and sweep. The
blading used nominally the same blade sections as the datum, and parametric studies
were conducted into various lean/sweep configurations to try to optimise the blade
performance. The final blade geometry also incorporated leading edge recambering
towards the fixed endwalls of both the rotor and stator. The '3D' blading demonstrated a
1.5% increase in efficiency (over the datum blading) at design flow rising to around 3%
at near stall along with an improvement in stall margin and pressure rise characteristic.
The design work was completed using the TRANSCode flow solver for both the
blade-to-blade solutions (used in the SI-S2 datum design calculation) and the fully 3D
solutions (for the advanced design and post datum design appraisal). The 3D solutions
gave a reasonable representation of the mid-span and main 3D flow features but failed to
model the corner and tip clearance flow accurately. An interesting feature of the low
speed flowfield was the circumferential variation in total pressure observed at exit from
all rotors for both designs. This was not present at high speed and represents one of the
main differences between the high and low speed flow. Unsteady modelling of mid-
height sections from the first stage indicate that part of this variation is due to the
potential interaction of the rotor with the downstream stator while the remainder is due
to the wake structure from the upstream stator convecting through the rotor passage.
Finally, the implications for a high speed design based on the success of the 3D low
speed design are considered.
23
Behrens, Christopher Karl. "An Experimental Investigation into NOx Control of a Gas Turbine Combustor and Augmentor Tube Incorporating a Catalytic Reduction System." Thesis, Monterey, Califonia : Naval Postgraduate School, 1990. http://handle.dtic.mil/100.2/ADA231427.
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Thesis (M.S. in Aeronautical Engineering)--Naval Postgraduate School, March 1990.<br>Thesis Advisor(s): Netzer, D. W. Second Reader: Shreeve, R. P. "March 1990." Description based on signature page as viewed on August 25, 2009. DTIC Descriptor(s): Air, augmentation, catalysis, catalysts, combustors, configurations, engines, fuels, gas generating systems, gas turbines, measurement, pressure, profiles, ratios, reduction, tubes, velocity. DTIC Identifier(s): Nitrogen oxides, NOx control, Gas turbines, Gas analyzers, Pollution abatement, computer programs, Emissions control, Exhaust augmentor tubes, Thesis. Author(s) subject terms: Nox control, gas turbine combustors; emissions control exhaust augmentor tubes; gas analyzers; pollution control. Includes bibliographical references (p. 73-74). Also available online.
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Eveker, Kevin M. "Model Development for active control of stall phenomena in aircraft gas turbine engines." Diss., Georgia Institute of Technology, 1993. http://hdl.handle.net/1853/12363.
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Cornwell, Michael. "Causes of Combustion Instabilities with Passive and Active Methods of Control for practical application to Gas Turbine Engines." University of Cincinnati / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1307323433.
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Kaptain, Tyler J. "Hardware Scaled Co-Simulation of Optimal Controlled Hybrid Gas-Electric Propulsion." Cleveland State University / OhioLINK, 2021. http://rave.ohiolink.edu/etdc/view?acc_num=csu1631634390032462.
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Kratz, Jonathan L. "Robust Control of Uncertain Input-Delayed Sample Data Systems through Optimization of a Robustness Bound." The Ohio State University, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=osu1429149093.
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Єнчев, Сергій Васильович, та Serhii Vasylovych Yenchev. "Синтез інтелектуальних систем керування авіаційними газотурбінними двигунами". Thesis, Національний авіаційний університет, 2020. https://er.nau.edu.ua/handle/NAU/44729.
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Проаналізовано принципи побудови, функції, задачі, методи й
алгоритми синтезу інтелектуальних систем керування авіаційними
газотурбінними двигунами. Досліджено структури та інформаційні потоки в
електронних системах керування авіаційними ГТД, створено комплекс
методик і алгоритмів ідентифікації авіаційних ГТД й обробки інформації в
САК ГТД на основі методів інтелектуального керування.
Сформульовано науково-методичні основи проектування
нейромережевих регуляторів у структурах ІСК авіаційними ГТД: навчання,
алгоритми синтезу та налаштування; формування структури ІСК ГТД та
інтелектуального вейвлет-фільтру. Розроблено методику синтезу нечітких
ІСК ГТД за допомогою методу гармонічної лінеаризації та алгоритмічне
забезпечення їх функціонування.
З позицій системного підходу запропоновано концепцію оптимізації
ІСК ГТД, керувальна частина якої являє собою єдиний математичний
оператор, що перетворює вхідну інформацію в керувальні впливи. На основі
концепції розроблено метод і методику оптимізації законів керування в ІСК
ГТД у процесі експлуатації на сталих та перехідних режимах за обраними
критеріями: швидкодія, мінімальна витрата палива.
Запропоновано вирішення задачі синтезу алгоритмів відмовостійкого
керування ІСК ГТД на основі нечіткої логіки та нейронних мереж.
Розроблено алгоритм і методику синтезу НМ-регулятора в складі ІСК ГТД.
Досліджено залежність показників якості керування САК від вибору
архітектури та структури НМ. Запропоновано алгоритм забезпечення
відмовостійкості САК ГТД, базований на використанні методу FDI, який
відрізняється тим, що виявлення відмов у системі здійснюється шляхом
порівняння елементів САК ГТД з аналогічними виходами елементів
еталонної нейромережевої моделі САК, налаштовуваній у режимі реального
часу, що дозволяє підвищити оперативність і достовірність виявлення відмов
у широкому діапазоні зміни роботи та характеристик САК ГТД.<br>The thesis analyses the synthesis of intelligent control systems of aircraft
gas turbine engines principles of construction, functions, tasks, methods and
algorithms. The thesis studies the structures and information flow in aviation gas
turbine engines electronic control systems and establishes the methods and
algorithms for identification of aviation gas turbine engines and information
processing in the system of automatic control system of gas turbine engines based
on intelligent control methods.
The study establishes scientific and methodological bases of designing
neural network regulators in the structures of intelligent control systems of aviation
gas turbine engines: training, synthesis algorithms and settings; intelligent control
systems of gas turbine engines formation and intelligent wavelet filter. The method
of synthesis of fuzzy intelligent control systems of gas turbine engines using the
method of balanced straight line approximation and algorithmic maintenance of
their functioning is developed.
The thesis proposes the concept of intelligent control systems of gas turbine
engines optimization in terms of system approach. The control part of the systems
is a single mathematical operator that converts input information into control
effects. The study provides the method and methodology for the intelligent control
systems of the gas turbine engine control laws optimization in the course of
operation in stable and transient modes according to the criteria: speed, minimum
fuel consumption, based on the abovementioned concept.
The thesis offers the solution to the problem of failure-resistant control
algorithms synthesis of intelligent control systems of gas turbine engines on the
basis of fuzzy logic and neural networks. The algorithm and method for the
synthesis of neural network regulator as a part of intelligent control systems of gas
turbine engines are developed. The study analyses the dependence of intelligent
control systems management quality on the choice of neuron network architecture
and structure. The failure-resistance algorithm for intelligent control systems of gas
turbine engines is proposed. The algorithm is based on the use of FDI method,
characterized in that the detection of failures in the system is carried out by
comparing elements of intelligent control systems of gas turbine engines with the
elements of the reference neural network model of intelligent control systems. The
reference model is used in real-time mode. Therefore, the reliability of the failures
detection in a wide work and characteristics variation range of intelligent control
systems of gas turbine engines.
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Ismail, Ibrahim H. "Simulation of aircraft gas turbine engine." Thesis, University of Hertfordshire, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.303465.
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Farahani, Arash. "Gas turbine engine static strip seals." Thesis, University of Sussex, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.444118.
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Kashinath, Karthik. "Nonlinear thermoacoustic oscillations of a ducted laminar premixed flame." Thesis, University of Cambridge, 2013. https://www.repository.cam.ac.uk/handle/1810/264291.
Full textAbstract:
Finding limit cycles and their stability is one of the central problems of nonlinear thermoacoustics. However, a limit cycle is not the only type of self-excited oscillation in a nonlinear system. Nonlinear systems can have quasi-periodic and chaotic oscillations. This thesis examines the different types of oscillation in a numerical model of a ducted premixed flame, the bifurcations that lead to these oscillations and the influence of external forcing on these oscillations. Criteria for the existence and stability of limit cycles in single mode thermoacoustic systems are derived analytically. These criteria, along with the flame describing function, are used to find the types of bifurcation and minimum triggering amplitudes. The choice of model for the velocity perturbation field around the flame is shown to have a strong influence on the types of bifurcation in the system. Therefore, a reduced order model of the velocity perturbation field in a forced laminar premixed flame is obtained from Direct Numerical Simulation. It is shown that the model currently used in the literature precludes subcritical bifurcations and multi-stability. The self-excited thermoacoustic system is simulated in the time domain with many modes in the acoustics and analysed using methods from nonlinear dynamical systems theory. The transitions to the periodic, quasiperiodic and chaotic oscillations are via sub/supercritical Hopf, Neimark-Sacker and period-doubling bifurcations. Routes to chaos are established in this system. It is shown that the single mode system, which gives the same results as a describing function approach, fails to capture the period-$2$, period-$k$, quasi-periodic and chaotic oscillations or the bifurcations and multi-stability seen in the multi-modal case, and underpredicts the amplitude. Instantaneous flame images reveal that the wrinkles on the flame surface and pinch off of flame pockets are regular for periodic oscillations, while they are irregular and have multiple time and length scales for quasi-periodic and chaotic oscillations. Cusp formation, their destruction by flame propagation normal to itself, and pinch-off and rapid burning of pockets of reactants are shown to be responsible for generating a heat release rate that is a highly nonlinear function of the velocity perturbations. It is also shown that for a given acoustic model of the duct, many discretization modes are required to capture the rich dynamics and nonlinear feedback between heat release and acoustics seen in experiments. The influence of external harmonic forcing on self-excited periodic, quasi-periodic and chaotic oscillations are examined. The transition to lock-in, the forcing amplitude required for lock-in and the system response at lock-in are characterized. At certain frequencies, even low-amplitude forcing is sufficient to suppress period-$1$ oscillations to amplitudes that are 90$\%$ lower than that of the unforced state. Therefore, open-loop forcing can be an effective strategy for the suppression of thermoacoustic oscillations. This thesis shows that a ducted premixed flame behaves similarly to low-dimensional chaotic systems and that methods from nonlinear dynamical systems theory are superior to the describing function approach in the frequency domain and time domain analysis currently used in nonlinear thermoacoustics.
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Siddiqi, Majid. "Turbine Engine Control and Diagnostics." The Ohio State University, 2005. http://rave.ohiolink.edu/etdc/view?acc_num=osu1420210543.
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Zedda, M. "Gas turbine engine and sensor fault diagnosis." Thesis, Cranfield University, 1999. http://dspace.lib.cranfield.ac.uk/handle/1826/9117.
Full textAbstract:
Substantial economic and even safety related gains can be achieved if effective gas
turbine performance analysis is attained. During the development phase, analysis can help
understand the effect on the various components and on the overall engine performance
of the modifications applied. During usage, analysis plays a major role in the assessment
of the health status of the engine. Both condition monitoring of operating engines and
pass off tests heavily rely on the analysis.
In spite of its relevance, accurate performance analysis is still difficult to achieve. A
major cause of this is measurement uncertainty: gas turbine measurements are affected by
noise and biases. The simultaneous presence of engine and sensor faults makes it hard to
establish the actual condition of the engine components.
To date, most estimation techniques used to cope with measurement uncertainty are
based on Kalman filtering. This classic estimation technique, though, is definitely not
effective enough. Typical Kalman filter results can be strongly misleading so that even
the application of performance analysis may become questionable. The main engine
manufactures, in conjunction with research teams, have devised modified Kalman filter
based techniques to overcome the most common drawbacks. Nonetheless, the proposed
methods are not able to produce accurate and reliable performance analysis.
In the present work a different approach has been pursued and a novel method
developed, which is able to quantify the performance parameter variations expressing the
component faults in presence of noise and a significant number of sensor faults. The
statistical basis of the method is sound: the only accepted statistical assumption regards
the well known measurement noise standard deviations. The technique is based on an
optimisation procedure carried out by means of a problem specific, real coded Genetic
Algorithm. The optimisation based method enables to concentrate the steady state
analysis on the faulty engine component(s). A clear indication is given as to which
component(s) is(are) responsible for the loss of performance. The optimisation
automatically carries out multiple sensor failure detection, isolation and accommodation.
The noise and biases affecting the parameters setting the operating point of the engine
are coped with as well.
The technique has been explicitly developed for development engine test bed analysis,
where the instrumentation set is usually rather comprehensive. In other diagnostic cases
(pass off tests, ground based analysis of on wing engines), though, just few sensors may
be present. For these situations, the standard method has been modified to perform
multiple operating point analysis, whereby the amount of information is maximised by
simultaneous analysis of more than a single test point. Even in this case, the results are
very accurate.
In the quest for techniques able to cope with measurement uncertainty, Neural Networks
have been considered as well. A novel Auto-Associative Neural Network has been
devised, which is able to carry out accurate sensor failure detection and isolation.
Advantages and disadvantages of Neural Network-based gas turbine diagnostics have
been analysed.
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Singh, Grewal M. "Gas Turbine Engine Performance Deterioration Modelling and Analysis." Thesis, Cranfield University, 1988. http://dspace.lib.cranfield.ac.uk/handle/1826/8068.
Full textAbstract:
In-service performance deterioration of gas turbine engines
can be identified, at the engine module level, in terms of
reductions in the component mass flow and the efficiency.
Continued operation of a deteriorated gas turbine is (i)
uneconomical and (ii) unsafe. Timely identification of the
faults and ensuing maintenance could prevent both. Gas Path
Analysis is a technique to establish the current performance
level of the gas turbines and identify the faulty modules.
Computer models can predict the off_design performance of gas
turbines by aero-thermo-dynamically matching the engine
components. This thesis describes the development of DETEM
(DEeteriorated Turbine Engine Model), a generalised computer
program, developed to model degraded gas turbine engines and
analyse faults.
The program has an integrated graphics module and creates
windows on the VDU terminal,for displaying the program output
and accepting the user input. This enables the user to compare
the results of two different types of runs at the same time.
The program incorporates sensor models that modify the output,
with noise and in bias, based on the sensor characteristics,
thus simulating a real engine. It is possible to simulate the
engine performance at design point, off-design and under
transient conditions. The runs could be for a "clean" and a
deteriorated engine.
Three techniques, iterative, fault coefficient matrix, and
a statistical best-estimation technique, have been used to
analyse the engine performance and identify the fault.
Analysis of two and three shaft turbo-shaft engines and two
spool turbo-fan and turbo-jet engines have been worked out in
the thesis. Effects of reducing the number of measurements and
measuring different engine parameters, on the accuracy of the
fault identification, have been studied.
The program is considered to have a potential for the
generation of fault trees for rule-based expert system
applied to gas turbine diagnostics. Because of the controlled
output to the screen, a direct comparison of two different
runs side by side, on the same screen, makes the program a
good teaching aid for gas turbine diagnostics.
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Roth, Richard. "Materials substitution in aircraft gas turbine engine applications." Thesis, Massachusetts Institute of Technology, 1992. http://hdl.handle.net/1721.1/13112.
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Nishimoto, Keane T. (Keane Takeshi) 1981. "Design of an automobile turbocharger gas turbine engine." Thesis, Massachusetts Institute of Technology, 2003. http://hdl.handle.net/1721.1/41810.
Full textAbstract:
Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2003.<br>Includes bibliographical references (leaf 24).<br>The turbocharger gas turbine engine was designed with the intent of being built as a demonstration for the Massachusetts Institute of Technology Department of Mechanical Engineering courses 2.005 and 2.006 to supplement material covered. A gas turbine operates on an open version of the Brayton cycle and consists of a compressor, a combustion chamber and a turbine. An automobile turbocharger was chosen because it contains a compressor and turbine on a common shaft. Designs for the combustion chamber, oil system, fuel system, and ignition system were created based on research of similar projects. Many of the necessary parts were also specified.<br>by Keane T. Nishimoto.<br>S.B.
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Moy, Habs M. (Habs Mern) 1967. "Commercial gas turbine engine platform strategy and design." Thesis, Massachusetts Institute of Technology, 2000. http://hdl.handle.net/1721.1/88328.
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Gulati, Ankush. "An optimization tool for gas turbine engine diagnostics." Thesis, Cranfield University, 2001. http://dspace.lib.cranfield.ac.uk/handle/1826/10699.
Full textAbstract:
A
major challenge faced by the Gas Turbine industry, both the users and the
manufacturers is the reduction of life cycle costs and safe running of a gas turbine. A
reduction in the costs can be achieved by reducing the development time while the engine
is in the
development stage and reducing operating costs for in service engines. One of
the ways of achieving these would be the use of sophisticated performance analysis and
diagnostic techniques.
Techniques for such purposes of diagnosis have developed a great deal over the last three
decades. The initial work was on gas path analysis, followed by use of conventional
techniques such as Kalman filters and Least squares algorithm for gas path analysis. The
last decade has seen a lot of work on the use of intelligent systems such as neural
networks, fuzzy logic and expert systems for such purposes. Though improvements have
been made over the
years, but all these techniques have major drawbacks, which make
their use in the current
stage of development very unlikely.
The use of
genetic algorithm based optimization technique for diagnostics of well instrumented
engines (development engines) was successfully made at Cranfield
University. The present work presents a technique for fault diagnostics of engines that are
relatively poorly instrumented. The work presents how the task is achieved by the use of
multiple operating point analysis and the use of a genetic algorithm based optimization
technique for optimization of an objective function that depends on the measurements
and the
corresponding value for changed performance and power setting parameters
obtained from the thermodynamic performance model of the engine. The main issues that
have been addressed are the choice and number of operating points and also the
development of the multi objective optimization technique.
The
technique is able to accurately identify the faulty components and quantify the fault.
The fault is
expressed in terms of a change in efficiency and capacity of the various
components. The optimization also carries out Sensor fault detection, isolation and
accommodation .The
technique has been tested on a number of engine types using
simulated data. These
engines have been chosen to cover a wide range of instrumentation
suites. The
advantages, drawbacks and the suggested method of application have also
been
presented.
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Nikolaidis, Theoklis. "Water ingestion effects on gas turbine engine performance." Thesis, Cranfield University, 2008. http://hdl.handle.net/1826/3516.
Full textAbstract:
Although gas turbine engines are designed to use dry air as the working fluid,
the great demand over the last decades for air travel at several altitudes and
speeds has increased aircraft’s exposure to inclement weather conditions.
Although, they are required to perform safely under the effect of various
meteorological phenomena, in which air entering the engine contains water,
several incidents have been reported to the aviation authorities about power
loss during flight at inclement weather. It was understood that the rain ingestion
into a gas turbine engine influences the performance of the engine and
particular the compressor and the combustor.
The effects of water ingestion on gas turbine engines are aerodynamic,
thermodynamic and mechanical. These effects occur simultaneously and affect
each other. Considering the above effects and the fact that they are timedependent,
there are few gas turbine performance simulation tools, which take
into account the water ingestion phenomenon.
This study is a new research of investigating theoretically the water ingestion
effects on a gas turbine performance. It focuses on the aerodynamic and
mechanical effects of the phenomenon on the compressor and the combustor.
The application of Computational Fluid Dynamics (CFD) is the basic
methodology to examine the details of the flow in an axial compressor and how
it is affected by the presence of water. The calculations of water film thickness,
which is formed on the rotor blade, its motion (direction and speed) and the
extra torque demand, are provided by a code created by the author using
FORTRAN programming language. Considering the change in blade’s profile
and the wavy characteristics of the liquid film, the compressor’s performance
deterioration is calculated.
The compressor and combustor’s deterioration data are imported to a gas
turbine simulation code, which is upgraded to calculate overall engine’s
performance deterioration. The results show a considerable alteration in
engine’s performance parameters and arrive at the same conclusions with the
relevant experimental observations.
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Stitzel, Sarah M. "Flow Field Computations of Combustor-Turbine Interactions in a Gas Turbine Engine." Thesis, Virginia Tech, 2001. http://hdl.handle.net/10919/30992.
Full textAbstract:
The current demands for higher performance in gas turbine engines can be reached by raising combustion temperatures to increase thermal efficiency. Hot combustion temperatures create a harsh environment which leads to the consideration of the durability of the combustor and turbine sections. Improvements in durability can be achieved through understanding the interactions between the combustor and turbine. The flow field at a combustor exit shows non-uniformities in pressure, temperature, and velocity in the pitch and radial directions. This inlet profile to the turbine can have a considerable effect on the development of the secondary flows through the vane passage.
This thesis presents a computational study of the flow field generated in a non-reacting gas turbine combustor and how that flow field convects through the downstream stator vane. Specifically, the effect that the combustor flow field had on the secondary flow pattern in the turbine was studied. Data from a modern gas turbine engine manufacturer was used to design a realistic, low speed, large scale combustor test section. This thesis presents the results of computational simulations done in parallel with experimental simulations of the combustor flow field.
In comparisons of computational predictions with experimental data, reasonable agreement of the mean flow and general trends were found for the case without dilution jets. The computational predictions of the combustor flow with dilution jets indicated that the turbulence models under-predicted jet mixing. The combustor exit profiles showed non-uniformities both radially and circumferentially, which were strongly dependent on dilution and cooling slot injection. The development of the secondary flow field in the turbine was highly dependent on the incoming total pressure profile. For a case with a uniform inlet pressure in the near-wall region no leading edge vortex was formed. The endwall heat transfer was found to also depend strongly on the secondary flow field, and therefore on the incoming pressure profile from the combustor.<br>Master of Science
41
Poppe, Christian. "Scalar measurements in a gas turbine combustor." Thesis, Imperial College London, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.264987.
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Groshenry, Christophe. "Preliminary design study of a micro-gas turbine engine." Thesis, Massachusetts Institute of Technology, 1995. http://hdl.handle.net/1721.1/10386.
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Liu, Chunmeni 1970. "Dynamical system modeling of a micro gas turbine engine." Thesis, Massachusetts Institute of Technology, 2000. http://hdl.handle.net/1721.1/9249.
Full textAbstract:
Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 2000.<br>Also available online at the MIT Theses Online homepage <http://thesis.mit.edu>.<br>Includes bibliographical references (p. 123).<br>Since 1995, MIT has been developing the technology for a micro gas turbine engine capable of producing tens of watts of power in a package less than one cubic centimeter in volume. The demo engine developed for this research has low and diabtic component performance and severe heat transfer from the turbine side to the compressor side. The goals of this thesis are developing a dynamical model and providing a simulation platform for predicting the microengine performance and control design, as well as giving an estimate of the microengine behavior under current design. The thesis first analyzes and models the dynamical components of the microengine. Then a nonlinear model, a linearized model, and corresponding simulators are derived, which are valid for estimating both the steady state and transient behavior. Simulations are also performed to estimate the microengine performance, which include steady states, linear properties, transient behavior, and sensor options. A parameter study and investigation of the startup process are also performed. Analysis and simulations show that there is the possibility of increasing turbine inlet temperature with decreasing fuel flow rate in some regions. Because of the severe heat transfer and this turbine inlet temperature trend, the microengine system behaves like a second-order system with low damping and poor linear properties. This increases the possibility of surge, over-temperature and over-speed. This also implies a potentially complex control system. The surge margin at the design point is large, but accelerating directly from minimum speed to 100% speed still causes surge. Investigation of the sensor options shows that temperature sensors have relatively fast response time but give multiple estimates of the engine state. Pressure sensors have relatively slow response time but they change monotonically with the engine state. So the future choice of sensors may be some combinations of the two. For the purpose of feedback control, the system is observable from speed, temperature, or pressure measurements. Parameter studies show that the engine performance doesn't change significantly with changes in either nozzle area or the coefficient relating heat flux to compressor efficiency. It does depend strongly on the coefficient relating heat flux to compressor pressure ratio. The value of the compressor peak efficiency affects the engine operation only when it is inside the range of the engine operation. Finally, parameter studies indicate that, to obtain improved transient behavior with less possibility of surge, over-temperature and over-speed, and to simplify the system analysis and design as well as the design and implementation of control laws, it is desirable to reduce the ratio of rotor mechanical inertia to thermal inertia, e.g. by slowing the thermal dynamics. This can in some cases decouple the dynamics of rotor acceleration and heat transfer. Several methods were shown to improve the startup process: higher start speed, higher start spool temperature, and higher start fuel flow input. Simulations also show that the efficiency gradient affects the transient behavior of the engine significantly, thereby effecting the startup process. Finally, the analysis and modeling methodologies presented in this thesis can be applied to other engines with severe heat transfer. The estimates of the engine performance can serve as a reference of similar engines as well.<br>by Chunmei Liu.<br>S.M.
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Savoulides, Nicholas 1978. "Development of a MEMS turbocharger and gas turbine engine." Thesis, Massachusetts Institute of Technology, 2004. http://hdl.handle.net/1721.1/17815.
Full textAbstract:
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 2004.<br>Includes bibliographical references.<br>As portable electronic devices proliferate (laptops, GPS, radios etc.), the demand for compact energy sources to power them increases. Primary (non-rechargeable) batteries now provide energy densities upwards of 180 W-hr/kg, secondary (rechargeable) batteries offer about 1/2 that level. Hydrocarbon fuels have a chemical energy density of 13,000-14,000 W-hr/kg. A power source using hydrocarbon fuels with an electric power conversion efficiency of order 10% would be revolutionary. This promise has driven the development of the MIT micro gas turbine generator concept. The first engine design measures 23 x 23 x 0.3 mm and is fabricated from single crystal silicon using MEMS micro-fabrication techniques so as to offer the promise of low cost in large production. This thesis describes the development and testing of a MEMS turbocharger. This is a version of a simple cycle, single spool gas turbine engine with compressor and turbine flow paths separated for diagnostic purposes, intended for turbomachinery and rotordynamic development. The turbocharger design described herein was evolved from an earlier, unsuccessful design (Protz 2000) to satisfy rotordynamic and fabrication constraints. The turbochargers consist of a back-to-back centrifugal compressor and radial inflow turbine supported on gas bearings with a design rotating speed of 1.2 Mrpm. This design speed is many times the natural frequency of the radial bearing system. Primarily due to the exacting requirements of the micron scale bearings, these devices have proven very difficult to manufacture to design, with only six near specification units produced over the course of three years. Six proved to be a small number for this development program since these silicon devices are brittle<br>(cont.) and do not survive bearing crashes at speeds much above a few tens of thousands of rpm. The primary focus of this thesis has been the theoretical and empirical determination of strategies for the starting and acceleration of the turbocharger and engine and evolution of the design to that end. Experiments identified phenomena governing rotordynamics, which were compared to model predictions. During these tests, the turbocharger reached 40% design speed (480,000 rpm). Rotordynamics were the limiting factor. The turbomachinery performance was characterized during these experiments. At 40% design speed, the compressor developed a pressure ratio of 1.21 at a flow rate of 0.13 g/s, values in agreement with CFD predictions. At this operating point the turbine pressure ratio was 1.7 with a flow rate of 0.26 g/s resulting in an overall spool efficiency of 19%. To assess ignition strategies for the gas turbine, a lumped parameter model was developed to examine the transient behavior of the engine as dictated by the turbomachinery fluid mechanics, heat transfer, structural deformations from centrifugal and thermal loading and rotordynamics. The model shows that transients are dominated by three time constants - rotor inertial (10⁻¹ sec), rotor thermal (lsec), and static structure thermal (10sec). The model suggests that the engine requires modified bearing dimensions relative to the turbocharger and that it might be necessary to pre-heat the structure prior to ignition ...<br>by Nicholas Savoulides.<br>Ph.D.
45
Hancock, Simon David. "Gas turbine engine controller design using multi-objective optimization techniques." Thesis, Bangor University, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.304616.
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ASSUMPCAO, VICTOR DOS SANTOS. "CONTROL STRATEGY OF A GAS TURBINE." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2012. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=21016@1.
Full textAbstract:
PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO<br>Após um período de baixa nas bacias hidrográficas, o Brasil investiu em novas fontes de geração de energia elétrica. O gás natural é um dos exemplos destas novas fontes de energia. Dentre as usinas usuárias deste combustível, existem aquelas que operam com turbinas a gás. Muitos estudos sobre modelagem de turbinas a gás, simulação de desempenho, diagnóstico e controle começaram devido a importância dessas usinas. Assim, torna-se necessário que estas usinas trabalhem com segurança e confiabilidade. Para garantir esta estabilidade, é necessário o desenvolvimento de um sistema de controle, capaz de realizar esta operação de geração de energia elétrica de forma satisfatória. O sistema de controle utilizado por estes equipamentos é o objeto de estudo deste trabalho. Neste trabalho, foi utilizado um modelo computacional de uma turbina a gás com duas características principais: um modelo computacional do sistema de controle, desenvolvido com base em uma nova metodologia de controle de turbina a gás, e um modelo termodinâmico existente de uma turbina a gás ligado à rede brasileira. O sistema de controle utiliza a temperatura de saída da turbina a gás (TET), como um fator de correção, para ajustar a temperatura da entrada da turbina (TIT). Esta temperatura (TIT) é utilizada como referência para o controle de fluxo de combustível injetado no interior da câmara de combustão. O modelo também controla o VIGV (pás diretoras móveis na entrada do compressor) através de uma curva utilizada no controle desta turbina a gás ligada à rede brasileira. O modelo computacional ainda apresenta um cálculo simplificado da composição molar dos gases de exaustão desta máquina térmica. Esta característica pode ser usada em combinação com um modelo de uma caldeira de recuperação de calor (HRSG), para simular uma condição de queima suplementar (duct burner), onde o principal objetivo é aumentar a potência produzida no ciclo. Os resultados da simulação foram comparados com os dados operacionais da usina brasileira.<br>After a period of water shortage, Brazil invested in new sources of electricity generation. Natural gas is an example of these new energy sources. Among these plants, some operate with gas turbines. Many studies about gas turbine modeling, performance´s simulation, diagnosis and control have started due the importance of these power plants. Thus, it is necessary that these plants work safely and reliably. To ensure this stability, it is necessary to develop a control system capable of performing this operation for generating electricity in a satisfactory manner. Then, the control system used by this equipment becomes the objective of this study. In this work, a computational model of a gas turbine was used with two main features: a developed computational model of control system based on a new methodology of gas turbine control and an existing thermodynamic model of a gas turbine connected to the Brazilian grid. The control system uses the turbine exhaust temperature (TET) as a corrective factor to adjust the turbine inlet temperature (TIT). TIT was used as a setpoint to control the fuel flow injected inside the combustor. The model also controls the IGV (Inlet Guide Vanes) by a control curve used in control of a specific gas turbine. There is a simplified calculation of the molar composition of the exhaust gas. This feature could be used in combination with a model of a heat recovery steam generator (HRSG) to simulate a condition with duct burners where the main objective is increase the cycle power. The results of simulation were compared to the operational data from the Brazilian power plant.
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Boumedmed, Abdelkader. "The use of variable engine geometry to improve the transient performance of a two-spool turbofan engine." Thesis, University of Glasgow, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.263451.
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Lee, Y. H. "Gas turbine engine health monitoring by fault pattern matching method." Thesis, Cranfield University, 1998. http://dspace.lib.cranfield.ac.uk/handle/1826/10714.
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The
gas turbine engine has a wide range of applications, these include industrial and
aerospace applications on locomotive, ferry, compressor and power generation, and
the most popular application will be for the air transportation. The application for air
transportation including military and commercial aircraft is highly sensitive to safety
concerns. The engine health monitoring system plays a major role for addressing this
concern, a good engine monitoring system will not only to provide immediate and
correct information to the engine user but also provide useful information for
managing the maintenance activities. Without a reliable performance diagnosis
module involved, there will be not possible to build a good health monitoring system.
There are many methodologies had been proposed and studied during past three
decades, and yet still struggling to search for some good techniques to handle
instrumentation errors. In order to develop a reliable engine performance diagnosis
technique, a fully understanding and proper handling of the instrumentation is
essential.
A engine performance fault pattern matching method has been proposed and
developed in this study, two fault libraries contains a complete defined set of 51963
faults was created by using a newly serviced fighter engine component data. This
pattern matching system had been verified by different approaches, such as compares
with linear and nonlinear diagnosis results and compares with performance sensitivity
analysis results by using LTF program engine data. The outcomes from the
verications indicate an encouraging result for further exploring this method.
In
conclusion, this research has not only propose a feasible performance diagnosis
techniques, but also developed and verified through different kind of approaches for
this techniques. In addition to that, by proper manipulating the created fault library, a
possible new tool for analyzing the application of instruments' implementation was
discovered. The author believes there will be more to study by using this created fault
pattern library. For instance, this fault pattern library can be treated as a very good
initial training sets for neural networking to develop a neural diagnosis technique.
This study has put a new milestone for further exploring gas turbine diagnosis
technique by using fault pattern related methods.
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Joo, Won-Gu. "Intake/engine flowfield coupling in turbofan engines." Thesis, University of Cambridge, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.319865.
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Burgess, C. A. R. "The application of aero gas turbine engine monitoring systems to military aircraft." Thesis, Cranfield University, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.232816.
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