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1
Abdelghaffar, Walid Abdel Aziz Ibrahim. "Modelling of fuel droplet heating in diesel engines." Thesis, University of Brighton, 2005. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.418570.
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Islam, Moni. "Numerical and experimental investigations of high-pressure diesel sprays." Thesis, Imperial College London, 2002. http://hdl.handle.net/10044/1/7987.
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Клименко, Олександр Миколайович. "Оцінка впливу регулювання температурного стану поршнів на техніко-економічні показники дизеля." Thesis, НТУ "ХПІ", 2016. http://repository.kpi.kharkov.ua/handle/KhPI-Press/21635.
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Дисертація на здобуття наукового ступеня кандидата технічних наук зі спеціальності 05.05.03 – двигуни та енергетичні установки. – Національний технічний університет "Харківський політехнічний інститут". – Харків, 2016.
Дисертаційна робота присвячена дослідженню впливу регульованого температурного стану поршнів дизеля різного призначення на його техніко-економічні показники. Розроблено та реалізовано методику оцінки якості дизеля при регулюванні інтенсивності масляного охолодження поршнів та керуванні моментом початку впорскування палива в камеру згоряння, а також при врахуванні моделі експлуатації енергетичної установки. Проведено експериментальні дослідження впливу температурного стану поршнів з низькотеплопровідним покриттям поверхні камери згоряння транспортного дизеля, а також зміни кута випередження впорскування палива на показники токсичності відпрацьованих газів, паливної економічності та температурний стан деталей камери згоряння. В результаті виконаного оптимізаційного дослідження запропоновано характеристичні карти керування масляним охолодженням поршнів та моментом початку впорскування палива для комплексного покращення техніко-економічних показників дизеля. Оцінено ефективність впровадження запропонованих заходів в автомобільних та тракторних дизелях та стаціонарних дизельгенераторах. Запропоновано методику врахування температурного стану найбільш теплонавантажених зон поршня в загальній методиці оцінки якості дизеля. Проведені розрахункові дослідження дозволили визначити ефективність регулювання температурного стану поршнів на ресурсну міцність його камери згоряння.Thesis for the science degree of the Candidate of technical sciences by speciality 05.05.03 – engines and power plants. – National Technical University "Kharkоv polytechnic institute", Kharkоv, 2016. Dissertation is devoted to research of complex influence of pistons temperature state regulation on the diesel engine technical and economic performance. In the dissertation work a method of estimating the quality of the diesel engine when regulating of the pistons temperature state, which takes into account indicators of exhaust gases toxicity and ICE fuel efficiency in each mode of the power plant operation is proposed. Experimental study of the effect of temperature condition of pistons with low conductive coating combustion chamber surface and changes the fuel injection timing angle on the exhaust gases toxicity, fuel economy and thermal condition of combustion chamber parts is done. As a result of the optimization research the characteristic cards control of pistons oilcooling and the fuel injection start for complex diesel engine technical and economic indicators improvement are proposed, the effectiveness of their use in automobile and tractor diesel engines and stationary diesel generators are estimated. The method of accounting of the most heat-loaded piston zones temperature state in general procedure of diesel quality assessment is proposed. Conducted estimated researches have allowed to define the effectiveness of pistons temperature state regulation on the combustion chamber resource strength.
4
Клименко, Олександр Миколайович. "Оцінка впливу регулювання температурного стану поршнів на техніко-економічні показники дизеля." Thesis, НТУ "ХПІ", 2016. http://repository.kpi.kharkov.ua/handle/KhPI-Press/21632.
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Дисертація на здобуття наукового ступеня кандидата технічних наук зі спеціальності 05.05.03 – двигуни та енергетичні установки. – Національний технічний університет "Харківський політехнічний інститут". – Харків, 2016.
Дисертаційна робота присвячена дослідженню впливу регульованого температурного стану поршнів дизеля різного призначення на його техніко-економічні показники. Розроблено та реалізовано методику оцінки якості дизеля при регулюванні інтенсивності масляного охолодження поршнів та керуванні моментом початку впорскування палива в камеру згоряння, а також при врахуванні моделі експлуатації енергетичної установки. Проведено експериментальні дослідження впливу температурного стану поршнів з низькотеплопровідним покриттям поверхні камери згоряння транспортного дизеля, а також зміни кута випередження впорскування палива на показники токсичності відпрацьованих газів, паливної економічності та температурний стан деталей камери згоряння. В результаті виконаного оптимізаційного дослідження запропоновано характеристичні карти керування масляним охолодженням поршнів та моментом початку впорскування палива для комплексного покращення техніко-економічних показників дизеля. Оцінено ефективність впровадження запропонованих заходів в автомобільних та тракторних дизелях та стаціонарних дизельгенераторах. Запропоновано методику врахування температурного стану найбільш теплонавантажених зон поршня в загальній методиці оцінки якості дизеля. Проведені розрахункові дослідження дозволили визначити ефективність регулювання температурного стану поршнів на ресурсну міцність його камери згоряння.Thesis for the science degree of the Candidate of technical sciences by speciality 05.05.03 – engines and power plants. – National Technical University "Kharkоv polytechnic institute", Kharkоv, 2016. Dissertation is devoted to research of complex influence of pistons temperature state regulation on the diesel engine technical and economic performance. In the dissertation work a method of estimating the quality of the diesel engine when regulating of the pistons temperature state, which takes into account indicators of exhaust gases toxicity and ICE fuel efficiency in each mode of the power plant operation is proposed. Experimental study of the effect of temperature condition of pistons with low conductive coating combustion chamber surface and changes the fuel injection timing angle on the exhaust gases toxicity, fuel economy and thermal condition of combustion chamber parts is done. As a result of the optimization research the characteristic cards control of pistons oilcooling and the fuel injection start for complex diesel engine technical and economic indicators improvement are proposed, the effectiveness of their use in automobile and tractor diesel engines and stationary diesel generators are estimated. The method of accounting of the most heat-loaded piston zones temperature state in general procedure of diesel quality assessment is proposed. Conducted estimated researches have allowed to define the effectiveness of pistons temperature state regulation on the combustion chamber resource strength.
5
Naeem, Muhamma. "Implications of aero-engine deterioration for a military aircraft's performance." Thesis, Cranfield University, 1999. http://hdl.handle.net/1826/3397.
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World developments have led the armed forces of many countries to become more
aware of how their increasingly stringent financial budgets are spent. Major expenditure
for military authorities is upon aero-engines. Some in-service deterioration in any
mechanical device, such as an aircraft's gas-turbine engine, is inevitable. However, its
extent and rate depend upon the qualities of design and manufacture, as well as on the
maintenance/repair practices followed by the users. Each deterioration has an adverse
effect on the performance and shortens the reliable operational life of the engine thereby
resulting in higher life cycle costs. The adverse effect on the life-cycle cost can be reduced
by determining the realistic fuel and life-usage and by having a better knowledge of the
effects of each such deterioration on operational performance. Subsequently improvements
can be made in the design and manufacture of adversely-affected components as well as
with respect to maintenance / repair and operating practices.
For a military aircraft's mission-profiles (consisting of several flight-segments),
using computer simulations, the consequences of engine deterioration upon the aircraft's
operational-effectiveness as well as fuel and life usage are predicted. These will help in
making wiser management decisions (such as whether to remove the aero-engines from the
aircraft for maintenance or to continue using them with some changes in the aircraft's
mission profile), with the various types and extents of engine deterioration. Hence
improved engine utilization, lower overall life-cycle costs and the optimal mission
operational effectiveness for a squadron of aircraft can be achieved.
6
Ulizar, Alvarez J. I. "Simulation of multi fluid gas turbines." Thesis, Cranfield University, 1998. http://hdl.handle.net/1826/3537.
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This work focuses on two main subjects: first, the development and validation
of a robust generic performance code for industrial gas turbines (GTSI) and, second,
the study of an innovative carbon dioxide/argon semi-closed cycle burning low
calorific gas coming from coal gasification. GTSI will be able to simulate open,
closed and semi-closed cycles at design and off-design conditions.
A comprehensive thermodynamic study of the properties of the most common
working fluids has been carried out, introducing the results in GTSI for a wide range
of temperatures and pressures, being easy to add other gases.
To make the code very general, in addition to gas turbines conventional
components, such as inlet, compressor,, intercooler, regenerator, combustor, turbine
and exhaust system, GTSI can model evaporative intercooler, steam injection and
reheat. The possibility of variable geometry was introduced in the compressor, steam
injector and turbine modules. Given the high temperatures in modem and future
turbines, a detailed cooling system modeling has been developed, being able to
predict cooling flow requirements according to different technology levels. The
control of the complete power plant has also been considered in detail, allowing the
user to select among different options. The code incorporates a simple steam turbine
bottoming cycle for a preliminary analysis of the combined cycle arrangement. In
addition to the conventional off-design simulations it is possible to carry out studies
involving engine deterioration and modification, or substitution, of components.
A validation process was carried out using different gas turbine arrangements.
The result has been satisfactory, although additional configurations should be
examined when more data is available.
As a direct application of GTSI, the conceptual design of the carbon
dioxide/argon semi-closed cycle was conducted. Several key performance factors
were considered in this study, such as the working fluid composition, the gas turbine
arrangement and the cooling technology. Other main parameters were selected
according to the state-of-the-art technology. Advanced concepts such as cryogenic
precooling and turbine stator internal cooling, together with improved component
efficiencies and higher temperatures were contemplated for a mid-long term future
design. The results obtained for the conventional cycles have not been very
promising, with slightly better values for the advanced cycles. Five of the most
interesting cycles were selected for off-design studies, evaluating the part-power
behaviour, the variable geometry requirement, etc. To complete the investigation, the
starting sequence of one of them was performed. Also, considering the possibility of
using existing turbomachinery, designed for air, in a semi-closed cycle pilot plant, the
operation of several gas turbine configurations was analysed.
7
Engelbrecht, Geoffrey E. "Modelling of premixed combustion in a gas turbine." Thesis, Cranfield University, 1998. http://hdl.handle.net/1826/3987.
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Three steady state combustion models, two turbulence models and a model for tK'6
prediction of NO., were implemented and investigated on a simple backward facing
step experiment as well as an experimental lean prevaporised premixed (LPP)
combustor. The three combustion models included the simple Eddy Break-up model
as well as a presumed probability density function (pdf) model and a form of the BML
crossing frequency flamelet model. These models were adapted to consider a
variable mixture fraction to account for a non-homogeneous fuel air mixture. The
two turbulence models used were the k-e and second moment models.
Despite being unable to capture the flame front spreading in the case of the
backward facing step, these predictions provided insight into the performance and
implementation of the models. All three of the combustion models, after appropriate
tuning, worked well for the LPP test combustor. This illustrates that such time
averaged models are useful for flows which do not contain large transient coherent
structures, such as that of the LPP test combustor and most practical engine
combustors designed today. The second moment closure turbulence model was
found to have the greatest impact on the flame front through the flow field predictions
rather than through counter gradient diffusion. The Eddy Break-up and BML
crossing frequency models both performed very well, qualitatively predicting the
correct trends. The additional consideration of flame front straining in the BML
crossing frequency model did not appear to significantly influence the flame front.
This is because the type of model adopted to predict this effect had a relatively
uniform influence everywhere in the flow. The presumed pdf model also performed
well and was additionally found to self ignite without the existence of hot products
when the inlet temperature was high enough. The NO., model faired well for a simple
experimental geometry. However, it considerably over predicted the NO., formed
within the LIPP test combustor, which was most probably due to poor boundary
conditions. Despite this overprediction, the results give insight into how to improve
the NQ, emissions for the experimental combustor.
8
Bennett, Guy Malcolm. "CFD modelling of ignition and combustion in diesel engines." Thesis, Imperial College London, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.408413.
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Sison, Kelly. "In-cylinder studies of diesel combustion with oxygenated fuels and multiple injections." Thesis, Brunel University, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.425198.
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Matthews, Alexander J. "Scramjet intakes." Thesis, University of Oxford, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.400217.
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Mahmoud, Osama Esmail. "An intelligent engine condition monitoring system." Thesis, University of Newcastle Upon Tyne, 2009. http://hdl.handle.net/10443/1665.
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The main focus of the work reported here is in the design of an intelligent condition monitoring system for diesel engines. Mechanical systems in general and diesel engines in particular can develop faults if operated for any length of time. Condition monitoring is a method by which the performance of a diesel engine can be maintained at a high level, ensuring both continuous availability and design-level efficiency. A key element in a condition monitoring program is to acquire sensor information from the engine, and use this information to assess the condition of the engine, with an emphasis on monitoring causes of engine failure or reduced efficiency. A Ford 70PS 4-stroke diesel engine has been instrumented with a range of sensors and interfaced to a PC in order to facilitate computer controlled data acquisition and data storage. Data was analyzed to evaluate the optimum use of sensors to identify faults and to develop an intelligent algorithm for the engine condition monitoring and fault detection, and in particular faults affecting the combustion process in the engine. In order to investigate the fault-symptom relationships, two synthetic faults were introduced to the engine. Fuel and inlet air shortage were selected as the faults for their direct relationship to the combustion process quality. As a subtask the manually operated hydraulic brake was adapted to allow automatic control to improve its performance. Two modes of controlling were designed for the developed automatic control of the hydraulic brake system. A robust mathematical diesel engine model has been developed which can be used to predict the engine parameters related to the combustion process in the diesel engine, was constructed from the basic relationships of the diesel engine using the minimum number of empirical equations. The system equations of a single cylinder engine were initially developed, from which the multi-cylinder diesel engine model was validated against experimental test data. The model was then tuned to improve the predicted engine parameters for better matching with the available engine type. The final four-cylinder diesel engine model was verified and the results show an accurate match with the experimental results. Neural networks and fuzzification were used to develop and validate the intelligent condition monitoring and fault diagnosis algorithm, in order to satisfy the requirements of on-line operation, i. e. reliability, easily trained, minimum hardware and software requirements. The development process used a number of different neural network architecture and training techniques. To increase the number of the parameters used for the engine condition evaluation, the Multi-Net technique was used to satisfy accurate and fast decision making. Two neural networks are designed to operate in parallel to accommodate the different sampling rate of the key parameters without interference and with reduced data processing time. The two neural networks were trained and validated using part of the measured data set that represents the engine operating range. Another set of data, not utilized within the training stage, has been applied for validation. The results of validation process indicate the successful prediction of the faults using the key measured parameters, as well as a fast data processing algorithm. One of the main outcomes of this study is the development of a new technique to measure cylinder pressure and fuel pressure through the measurement of the strain in the injector body. The main advantage of this technique is that, it does not require any intrusive modification to the engine which might affect the engine actual performance. The developed sensor was tested and used to measure the cylinder and fuel pressure to verify the fuel fault effect on the combustion process quality. Due to high sampling rate required, the developed condition monitoring and fault diagnosis algorithm does not utilize this signal to reduce the required computational resources for practical applications.
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Manuvelpillai, Joël Umakanthan. "Adsorption of aromatics with diesel engine derived soot." Thesis, University of Bristol, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.495643.
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The diesel engine combustion process produces carbonaceous deposits known as soot. Such carbonaceous deposits are accumulated at critical locations in a diesel engine, with detrimental effect on engine performance. The main objective of this project is to explore the role of polymers and additives, on the stability of carbon black, soot model, in organic solvents. Lubrizol uses a wide range of polyolefin derivatives, such as polar head groups grafted onto saturated polymers, as lubricants in diesel engine oil. A new generation of additive, known as a Dispersant Viscosity Modifier, that has dual functional properties in a single molecule, has been synthesised. The additive can be used for both dispersancy and viscosity modification. It is composed of a long hydrocarbon chain and a polar head group.
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Abdul-Karim, Zainal A. "Direct injection diesel engine combustion diagnostics." Thesis, Loughborough University, 2004. https://dspace.lboro.ac.uk/2134/7681.
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The demand for the protection of the environment from air pollution and reduction of carbon dioxide has resulted in worldwide exhaust emissions regulations imposed on the diesel engines. Fortunately, diesel engine offers the best fuel economy and low emissions of carbon dioxide of most engines currently available. However, the engine's inherent drawbacks are that the engine is heavy, noisy, and expensive, in addition to producing significant level of particulates and nitrogen oxides emissions. The present research attempts to understand the combustion characteristics and emissions trade-off by experimental investigations of the diesel engine using a production Lister Petter 2.97 litres, four-cylinder, high-speed, direct injection diesel engine. The investigation involved the analysis of the in-cylinder pressure data, heat release rate calculation and exhaust gas measurements of various injectors having different nozzle geometry. The engine experiments cover both the investigation of the fuel injection and the engine operating parameters such as injection rate, nozzle geometry, the engine load and speed. The effects of each parameter on ignition delay, heat release rate, nitrogen oxides emissions, smoke density, and total hydrocarbon levels were investigated. Two complementary diagnostic techniques were employed in order to assist in understanding the injection characteristics. The first technique involved the imaging of the fuel sprays from the different injectors in a constant volume spray chamber using a CCD camera. The images were than process using a dedicated image processing software. The second technique involved the measurements of the fuel injection rates from the injectors using the Bosch Tube meter. A three-zone model was developed to determine the heat release rate of combustion. The cylinder pressure data was used to validate the model written in Matlab computer programme. The model is based on the principles of the First Law of Thermodynamics applied to the three zones, formed due to the fuel injection into the combustion chamber. The heat release rate profiles produced by the model were used to analyse the formation of pollutants that were measured in the exhaust gas. The results showed that injectors with large nozzle hole diameters produced high smoke levels, especially at high engine load conditions with small increase in NOx. These injectors also caused the sprays to impinged on the combustion chamber walls at high load conditions. On the other hand, injectors having small nozzle hole diameters produced high levels of NOx while the smoke emission levels were low. The effect of nozzle geometry has little significant on the emissions of THC.
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Kim, Sogkyun. "Fuzzy modelling and control for gas turbine altitude relighting." Thesis, University of Sheffield, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.421225.
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Castres, Fabrice. "Mode detection in turbofan inlets." Thesis, University of Southampton, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.438539.
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Goh, Keng Boon. "Fault diagnosis and control of a diesel power generator using sliding mode techniques." Thesis, University of Leicester, 2004. http://hdl.handle.net/2381/30217.
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The sliding mode concept, which is based on the notion of a variable structure system, has inherent advantages of robustness and performance specification and is here applied to the problems of fault diagnosis and control of the diesel engine. A real-time condition monitoring and fault diagnosis system and also control system using sliding mode techniques are described. The designs are assessed through tests on a particular Perkins diesel-electric power generator. A model-based approach incorporating a non-linear sliding mode observer scheme is proposed for fault monitoring. The diesel engine coolant system is considered. The system parameters are monitored using the concept of the equivalent injection signal which is required to maintain the sliding mode. The proposed diagnostic scheme is shown to be robust in estimating component parameters. The approach is applicable to many automotive engine approach problems and is cost effective as only low cost temperature sensors are involved in the implementation. The engine control strategy investigates both model-based and model-free sliding mode control techniques. The development of an engine model appropriate for speed control has been considered using closing-loop event-based system identification. Several control algorithms are proposed. Real-time speed control systems have been designed and implemented using Matlab/Simulink/dSPACE. The proposed model-based and model-free controllers show good tracking performance and disturbance rejection properties. The proposed model-free controller is shown to be an appropriate candidate for industrial control of the diesel engine system. The established gain-tuning algorithms allow non-experts to maintain and tune the resulting control schemes.
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Dellis, Polichronios. "Aspects of lubrication in piston cylinder assemblies." Thesis, Imperial College London, 2005. http://hdl.handle.net/10044/1/45467.
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The main objective of the project is to characterise piston ring lubrication in reciprocating test rigs and engines in terms of film thickness as a function of oil properties, reciprocating speed and load. A purpose-built test rig, which consists of a moving liner and a fixed piston ring, is used to measure the oil film thickness employing the capacitance and laser induced fluorescence (LIF) techniques. The intensity of the fluorescent light measured as voltage is interpreted as film thickness through calibration. Ring profile fitting is being used as the standard calibration method, but also a dynamic technique has been proposed whereby a groove of known depth on a piston ring specimen is used to provide in-situ dynamic calibration, circumventing the uncertainties of oil film temperature and properties variation during the cycle. A micrometer based static calibration method is compared directly to the dynamic one. The power output of the fibres should be taken into account as well as background noise and resident voltage on the fluorescence detector. Extensive oil parametric studies have been conducted and oil film thickness, LIF, friction and oil film pressure measurements are presented and compared for different speed, load, temperature, lubricant type and piston-ring geometry. The goal of enhancing the repeatability of the parametric study was achieved through the different positioning of the capacitance transducer and through the increased rigidity of the simulation rig. Useful results were drawn and the effect of properties such as viscosity, viscosity index, HTHS, piston - ring curvature and ring "effective width" on film thickness, film pressure and friction could be determined. Viscosity remains an important factor. Oil flow visualisation using a CCD camera allowed observation of cavitation throughout the stroke through a glass liner. At mid-stroke the presence of string cavities was evident, whereas near the dead centres the initiation of cavitation was observed in the form of fern-shaped cavities at the diverging wedge of the piston ring specimen at all times. The cavities take the shape of ferns, grown ferns, fissures, strings and bubbles. The existence of the cavities, previously identified indirectly with the LIF technique, was further supported by measurements using a new aluminium liner which incorporates a miniature pressure transducer used for the first time for oil film pressure measurements and an optical fibre. The oil film pressure measurements provided further support to the interpretation of cavitation at different parts of the stroke. The transition between different cavitating conditions (from P vapour to P atm) previously identified in the minimum oil film thickness measurement signal was further supported by the addition of the glass liner and the pressure transducer. Eventually, an insight was obtained into the onset and development of cavitation in the piston assembly via the simulation test rig, which will encourage further efforts in modelling cavitation under a much wider range of operating conditions than those examined here. Engine testing under motoring conditions was conducted in a modified single cylinder engine with parts of the liner cut and fitted with quartz windows for visualisation experiments. Comparable cavity forms to the test rig were identified and an approach towards their formation is presented. It became clear that the numerous factors affecting the lubrication between the piston-rings and cylinder liner in the engine are giving a different picture compared to the single-ring test rig where the structures are more uniform and the transition fi-om one cavitation type to another is much clearer. The unavailability of the oil film pressure measurements for the engine, though, does not support as strongly the findings from imaging. The top compression ring operates under starved lubrication conditions. Oil droplets were captured by the camera emerging from the ring side clearances that contribute to oil transport. Higher magnification imaging gave further evidence and was compared with previous engine research on oil transport. The engine study was limited by the unclear images obtained from the CCD camera and the window size which on one hand has the required size for the fixture firing tests and on another is quite small to provide adequate information about the residence time of the cavities that were identified. Another limiting factor of the study regarding the simulation test rig is that it can only provide data for the case of atmospheric conditions.
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Demosthenous, Alexis. "Soot formation and oxidation in a high-pressure spray flame." Thesis, Queen Mary, University of London, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.424461.
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Vargas, Gabriella Margarita Ascanio. "Performance monitoring and full diagnosis of a diesel engine turbocharger." Thesis, University of Sussex, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.494826.
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Turbocharging systems are of high importance in the enhancement of engine power and efficiency. Faults in such systems may cause increased emissions levels beyond those set by legislation, and may also compromise fuel efficiency. This thesis investigates the application of system identification and vibration signal analysis techniques for the performance monitoring of turbocharged diesel engines by exploring turbocharger behaviour. The first technique is based on the use of system identification to build models representing the input and output relationship of an engine process. In this case, torque demand is the input, and the turbocharger speed is the output in a medium duty, turbocharged diesel engine. The proposition set here is that the model that can be derived does not have to reflect the complexity of the physical system. Hence, if simple models can be derived, any deviation from the model of normal operation, if adhering to some principles, could indicate the existence of a fault in a system. Dynamic linear auto-regressive moving averages with exogenous input (ARMAX) models were estimated to represent the relationship between input and output. The models have been used to demonstrate the capability of the proposed technique to diagnose faults.
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Talbot-Weiss, Jonathan. "SFC improvements from turbo-generating heavy-duty diesel engines." Thesis, University of Sussex, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.496856.
Full textAbstract:
This thesis describes the development of high efficiency turbochargers and turbogenerators to significantly increase the power to weight ratio and reduce both the fuel consumption and emissions from heavy duty diesel engines. A literature overview is provided for turbomachinery based exhaust energy recovery projects in the public domain. The technologies are discussed in detail and compared using real test data. The thesis describes some design issues that were experienced during engine testing one with a heat shield and one with a volute - and how finite element analysis was used to generate solutions and long term evolutions in the designs. A variable nozzle guide vane ring was designed but seizing of the mechanism occurred during testing. A low friction coating was shown to be the solution.
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Plianos, Alexandros. "Nonlinear modelling and control of turbocharged diesel engines." Thesis, University of Sussex, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.496800.
Full textAbstract:
The main focus of this thesis is the investigation of nonlinear control designs on the airpath of a diesel engine equipped with exhaust gas recirculation (EGR) and variable geometry turbocharger (VGT). This problem presents strong couplings between controlled variables and actuators, since both EGR and VGT flows are driven by gases in the exhaust manifold. An additional coupling arises from the common shaft of the compressor and the turbine. The multivariable, highly nonlinear dynamics of the system gives motivation for model-based nonlinear control. Firstly, an eighth order mean-value model of the diesel engine is derived. This is consequently used to perform closed-loop simulations and to tune the controller gains offline. To reduce the complexity of the controllers, a third-order mean-value is used to design the nonlinear controllers.
22
Parra, Fernando Lopez. "Computational study on the effect of fuel stream perturbations on soot and NOx emissions in turbulent diffusion flames and applications to IC diesel engines." Thesis, University of Manchester, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.488992.
Full textAbstract:
The work contained in this thesis presents a computational study on the effects of fuel stream perturbations in non-premixed flames in terms of pollutant formation (soot and NOx), including the application to a practical case scenario, such as direct injection diesel engine. The initial part of the work concentrates on the implementation in FLUENT of a soot model that is based on the Eddy Dissipation concept of Magnussen, which accounts for the effects of small scale turbulence in the formation and depletion of soot particles.
23
Nivesrangsan, Pornchai. "Multi-source, multi-sensor approaches to diesel engine monitoring using acoustic emission." Thesis, Heriot-Watt University, 2004. http://hdl.handle.net/10399/1124.
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Tan, Yiping. "Automotive diesel turbocharger investigation." Thesis, University of Bath, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.437605.
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Zweiri, Yahya Hashem. "Non-linear modelling and estimation for diesel engines." Thesis, King's College London (University of London), 2003. https://kclpure.kcl.ac.uk/portal/en/theses/nonlinear-modelling-and-estimation-for-diesel-engines(6cc4a92f-924e-4223-93c2-3c010321a5a5).html.
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Stewart, Jill. "Combustion diagnostics of a dual fuel CI engine : an experimental and theoretical study." Thesis, Loughborough University, 2006. https://dspace.lboro.ac.uk/2134/7840.
Full textAbstract:
The term 'dual fuel' refers to a compression ignition engine where a small quantity of diesel fuel called the pilot is used to ignite a second gaseous fuel which is the primary energy source. The motivation to use dual fuel has traditionally been economic, as the primary fuel is often less expensive than the distillate fuel it replaces. However, some benefits in terms of the reduced emissions of smoke and oxides of nitrogen (NOx) can also be achieved. In this research, a small, direct injection diesel engine was converted to dual fuel operation. This engine is typical of those used in stationary power generation applications. A review of literature revealed that whilst performance and emissions trends were well established for indirect injection engines, little research had been conducted on a direct injection engine. In particular, this class of small, high speed industrial engine had been somewhat neglected, partly because they have been subject to less stringent emissions legislation than their automotive counterparts. By performing a detailed investigation ' into the errors and assumptions that have a bearing on the three zone technique, it was possible to challenge some previous assumptions regarding the dual fuel combustion process. Namely, the theory that the pilot bums in two separate initial stages was found to be a deficiency of previous analysis techniques and therefore incorrect. It was found that as the proportion of the gaseous fuel was increased, the combustion process retained similar characteristics and magnitudes of mass burned to diesel until all but the highest equivalence ratios. At this point, the premixed and diffusion burning periods merged, but continued to show a fundamental dependence on the pilot ignition and the combustion processes were never independent of the pilot. The range of equivalence ratios over which the transition between the two patterns occurs is firstly a function of the primary fuel, and secondly a function of the operating conditions (such as in cylinder temperature). It is proposed that the dual fuel combustion process is better described as a diesel combustion process with a modified diffusion burning period that results from the gaseous fuel concentration and type. By using this explanation, it was identified that the emissions characteristics of the engine could be modified through the use of a second fuel. The primary fuel can reduce the initial mass burning rates (to reduce NOx) and simultaneously elevated the diffusion burning rates (to reduce smoke emissions). This provides an alternative, beneficial means by which the classic diesel NOx-Particulate trade-off can be manipulated. Butane was found to be unsuitable for this type of engine, and propane consistently yielded the best performance and emissions trends. Additionally, it was found that the addition of small quantities of methane or propane can result in disproportionately large reductions in smoke and NOx without the penalty of increased carbon monoxide and unburned hydrocarbons.
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McGowan, D. J. "Integration of gen-set control." Thesis, Queen's University Belfast, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.411043.
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Brooks, Thomas D. "Split-main fuel injection strategies for diesel engines and their influence on emissions and fuel consumption." Thesis, University of Nottingham, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.417186.
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Sautermeister, Falko Alexander. "Piston ring lubrication-influence of sulphuric acid formation from high sulphur content fuel." Thesis, University of Leeds, 2012. http://etheses.whiterose.ac.uk/3132/.
Full textAbstract:
Large 2-stroke marine diesel engines burn high sulphur content residual fuel. The sulphur converts to aqueous sulphuric acid, H2SO4, and condenses on the cylinder liner surface, where it causes corrosive attack when not neutralised by the high alkaline reserve in the lubricant. Cylinder liner wear and deposit formation are observed to reflect poor lubricant distribution, surface temperature and sulphur fuel content, which all influence acid concentration. Currently neglected by the industry, is the catalysing action of H2SO4 on lubricant degradation and the rheology of entrained droplets in the oil film, which was the motivation for this study. To understand the basic interaction of H2SO4 with the lubricant film, the Saturated hydrocarbon squalane, C30H62, was chosen as a simple model oil in addition to fully formulated lubricants and their corresponding API Group I base oils. Interfacial tension between oil and aqueous solutions of H2SO4 was measured. Contact angles of aqueous solutions of H2SO4 immersed in C30H62 on piston ring chrome coating compared to grey cast iron cylinder liner material were measured. Fully formulated lubricant and API Group I base oil was used pure and emulsified with H2SO4 to lubricate a piston ring/ cylinder contact on a Plint TE77 Tribometer. The main analytical techniques were the light microscope, SEM/EDX, XPS, FTIR, laser diffraction particle size characterisation, white-light-interferometer and viscometer. Inter facial tension measurements of aqueous H2SO4 against C30H62 reveal a close relationship with the dissociation of H2SO4, which is also reflected by the formation of bituminous emulsions with API Group I base oil when above 40% w/wH2SO4 and formation of solids when above 80% w/wH2SO4 and high temperatures of around 120–165°C or long storage times. For pure water, the contact angles were found to be large while they were small for concentrated sulphuric acid. Contact angles on chrome coating were bigger than on grey cast iron. Advancing contact angles were larger than static and receding contact angles, which was expected. During the TE77tests,the degradation temperature of the base oil was lowered when in contact with H2SO4 from 250 to 80°C for oxidation, from 300 to 170°C for nitration and from 300 to 120°C for deposit formation. Over all the appearance of the surfaces improved when sulphuric acid was added to both, the API Group I base oil and the fully formulated lubricant.
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Attia, Osama Abdel Moniem Mohamied. "Finite element static, dynamic, and flutter analysis of rotating composite layered plates and shells." Thesis, Cranfield University, 1996. http://hdl.handle.net/1826/4052.
Full textAbstract:
This thesis introduces new conforming and non-conforming finite elements for the
static and dynamic analysis of rotating composite layered plates and shells. The
elements consider parabolic distributions of transverse shear stresses, and based on
Lagrangian and Hermitian shape functions. They can deal with variable thickness
distributions as well as uniform distributions, and they are fully capable to deal with
rotating plate and shell structures, i. e. centrifugal stiffening and Coriolis force effects
are considered. Natural frequency analysis, forced vibration analysis, and flutter
analysis of composite layered plate and shell structures, employing those elements,
have been investigated. A computer programming package based on the developed
theory was designed, and it is machine independent and user friendly. A modular
approach was adopted in the package structure to allow any further development to
be considered. Efficient frontal solvers were adopted in the package for different
types of analysis. The developed package has been successfully validated on a main
frame computer (VAX), Unix workstations, and personal computers. Several case
studies were investigated and the results obtained were compared with corresponding,
published theoretical and/or experimental work. The package has proved to be a very
useful tool for the design optimization of composite layered plates and shells by
means of using different fibre angles for different layers so as to achieve the required
strength and/or stiffness.
31
Fowler, Andrew. "A new advanced turbine-stage test facility : the concept, design, construction and commissioning." Thesis, University of Oxford, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.386786.
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Nikpour, B. "Measurement of the performance of a radial inflow turbine." Thesis, University of Manchester, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.282899.
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Robotham, William. "The elastic-plastic buckling behaviour of shafts." Thesis, University of Nottingham, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.323611.
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Lucas, Simon Charles. "Higher specific speed impulse turbines." Thesis, University of Reading, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.270200.
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Hughes, Adam William. "Investigation of tip-driven thruster and waterjet propulsion systems." Thesis, University of Southampton, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.322015.
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Dunkley, Michael John. "The aerodynamics of intermediate pressure turbines." Thesis, University of Cambridge, 1998. https://www.repository.cam.ac.uk/handle/1810/272045.
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Knife, S. "Propulsion system safety analysis methodology for commercial transport aircraft." Thesis, Cranfield University, 1997. http://hdl.handle.net/1826/4256.
Full textAbstract:
Airworthiness certification of commercial transport aircraft requires a
safety analysis of the propulsion system to establish that the probability of a
failure jeopardising the safety of the aeroplane is acceptably low. The
needs and desired features of such a propulsion system safety analysis are
discussed, and current techniques and assumptions employed in such
analyses are evaluated. It is concluded that current assumptions and
techniques are not well suited to predicting behaviour of the propulsion
system in service. The propulsion accident history of the high bypass ratio
commercial transport fleet is reviewed and an alternate approach to
propulsion system safety analysis is developed, based on this accident
history. Features of the alternate approach include quantified prediction of
propulsion related crew error, engine-level reliability growth modelling to
realistically predict engine failure rates, and quantified credit for design
features which mitigate the effects of propulsion system failures. The
alternate approach is validated by applying it to two existing propulsion
systems. It is found to produce forecasts in good agreement with service
experience. Use of the alternate approach to propulsion system safety
analysis during design and development will enable accurate prediction of
the expected propulsion related accident rate and identification of
opportunities to reduce the accident rate by incorporating mitigating
features into the propulsion system/ aeroplane design.
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Robinson, Christopher J. "End-wall flows and blading design for axial flow compressors." Thesis, Cranfield University, 1991. http://dspace.lib.cranfield.ac.uk/handle/1826/6929.
Full textAbstract:
The flow in multistage axial flow compressors is
particularly complex in nature because of the proximity of
moving bladerows, the growth of end-wall boundary layers and
the presence of tip and seal leakages and secondary flow.
The problems associated with these phenomena are at their
most acute in the latter, subsonic stages of the core
compressor, where Reynolds numbers are modest and the
blading has low aspect ratio. Indeed, much of the
inefficiency of axial stages is believed to be associated
with the interaction between blading and end-wall flows.
The fact that the end-wall flow phenomena result in
conditions local to the blade which are quite different
from those over the major part of the annulus was
appreciated by many of the earliest workers in the axial
turbomachinery field. However, experiments on blading
designs aimed specifically at attacking the end-loss have
been sparse.
This thesis includes results from tests of conventional
and end-bent blading in a four-stage, low-speed, axial
compressor, built specifically for the task, at a scale
where high spatial measurement resolution could be readily
achieved within the flowpath. Two basic design styles are
considered: a zero a0 stage with DCA aerofoils and a
low-reaction controlled-diffusion design with cantilevered
stators.
The data gives insight into the flow phenomena present in
'buried' stages and has resulted in a much clearer
understanding of the behaviour of end-bent blading. A
3D Navier-Stokes solver was calibrated on the two
low-reaction stators and was found to give good agreement
with most aspects of the experimental results. An improved
design procedure is suggested based on the incorporation
of end-bends into the throughflow and iterative use of the
3D Navier-Stokes solver.
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Addison, John Stephen. "Wake-boundary layer interaction in axial flow turbomachinery." Thesis, University of Cambridge, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.357704.
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Leontopoulos, Chris. "Vibration analysis for the design on a turbo-generator based powertrain for hybrid vehicles." Thesis, Imperial College London, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.284809.
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Brayton, Simon Nicholas. "Hot wire instrumentation for unsteady aerodynamic measurements in a rotating gas turbine stage." Thesis, University of Oxford, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.390399.
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Kuk, Victor H. M. "An investigation of particle trajectories and particle impact points in turbine film cooling hole system." Thesis, University of Oxford, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.294380.
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Slater, J. T. D. "Three-dimensional aerodynamic studies of a turbine stage in a transient flow facility." Thesis, University of Oxford, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.358729.
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Nascimento, M. A. R. "The selective bleed variable cycle engine." Thesis, Cranfield University, 1992. http://dspace.lib.cranfield.ac.uk/handle/1826/7359.
Full textAbstract:
A new concept in aircraft propulsion is described in this work. In particular, variable jet engine is investigated for supersonic ASTOVL aircraft. This engine is a Selective Bleed Variable Cycle, twin shaft turbofan. At low flight speeds the engine operates as a medium bypass turbofan. At supersonic cruise it operates as low bypass turbofan without reheat. The performance of the engine and its components is analyzed using a novel matching procedure. Off-design engine performance characteristics are explained, compressor running lines are shown, and variable geometry requirements are described.
The performance analysis shows that fuel savings are significant, thus reducing aircraft take-off weight. The major advantage of this engine is that all the components are used continuously for all operating modes, thus incurring low weight penalties. The benefits predicted by this preliminary investigation indicate that further research on this engine should be carried out.
The matching procedure developed and described shows itself to be very effective for two-shaft engines with a fixed geometry LP turbine. The method can also be extended to three shaft cases with or without a variable geometry LP turbine.
Extensive development of compressor and turbine design and performance software has been undertaken.
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Rolston, Stephen Carson. "An application of passive control for supersonic sidewall intakes." Thesis, Queen's University Belfast, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.359123.
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Al-Ajmi, Rashed. "Evaluation of vortex cooling systems for turbine blades." Thesis, Cardiff University, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.364475.
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Isaias, Loizos. "Performance simulation of a medium speed diesel engine under optimal and fault conditions." Thesis, University of Newcastle Upon Tyne, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.388759.
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Zhou, Ji. "Intelligent fault diagnosis with applications to gas turbine engines." Thesis, University of Sheffield, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.284354.
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Montazeri-Gh, Morteza. "Active control of surge in an aircraft compressor." Thesis, Cranfield University, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.309637.
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Monmont, Franck. "Experimental and theoretical study of the two-phase flow inside a lean premixed prevaporised combustor." Thesis, Cranfield University, 1999. http://dspace.lib.cranfield.ac.uk/handle/1826/10576.
Full textAbstract:
A
experimental study of the two-phase flow inside a lean premixed prevaporised
combustor has been carried out in order to evaluate the capabilities of large eddy
simulations
applied to engineering applications. To this end, a existing LPP design was
modified in order to
simplify the injection mechanisms involved and gain a optimum
optical access if the critical injection region. The liquid and the gas phase inside the LPP
module are then characterised with the help of non-invasive laser techniques, namely
PDA for the
liquid phase, LDA for the airstream and PLIF for the vapour phase. Relevant
information
regarding droplet sizes, droplet velocity, airstream velocity and fuel
placement have thus been collected. The measurements are then evaluated against flow
solutions
computed by a Eulerian-Lagrangian ite-volume solver. A hybrid
RANS/LES
modelling strategy has been adopted for the gas phase and the Lagrangian
tracking procedure has been updated to predict the influence of the gas turbulence on the
droplet dispersion, and the heat penetrating the droplet during its evaporation. This
simulation is
finally matched against ZD and 3D steady RANS solution in a attempt to
demonstrate the
superiority of the time dependent approach.