After undergoing a study about current engine modelling and mapping approaches as well as the engine modelling requirements for different applications, a major problem found to be present is the extensive and time consuming mapping procedure that every engine has to go through so that all control parameters can be derived from experimental data. To improve this, a cycle-by-cycle modelling approach has been chosen to mathematically represent reciprocating engines starting by a complete dynamics crankshaft mechanism model which forms the base of the complete engine model. This system is modelled taking into account the possibility of a piston pin offset on the mechanism. The derived Valvetrain model is capable of representing a variable valve lift and phasing Valvetrain which can be used while modelling most modern engines. A butterfly type throttle area model is derived as well as its rate of change which is believed to be a key variable for transient engine control. In addition, an approximation throttle model is formulated aiming at real-time applications. Furthermore, the engine inertia is presented as a mathematical model able to be used for any engine. A spark ignition engine simulation (SIES) framework was developed in MATLAB SIMULINK to form the base of a complete high fidelity cycle-by-cycle simulation model with its major target to provide an environment for virtual engine mapping procedures. Some experimental measurements from an actual engine are still required to parameterise the model, which is the reason an engine mapping (EngMap) framework has been developed in LabVIEW, It is shown that all the moving engine components can be represented by a single cyclic variable which can be used for flow model development.

Suction caissons are a new foundation option for offshore wind turbines. This thesis is focussed on the behaviour of suction caisson foundations in sand and in clay during installation, and under subsequent vertical and combined moment-lateral loadings. The research is based on extensive experimental work carried out using model scaled caissons. The analysis of the results allowed the determination of parameters for hyperplasticity models. Model caissons were vertically loaded in loose and dense sands to study in service states and plastic behaviour. Bearing capacity increased with the length of the caisson skirt. The bearing capacity formulation showed that the angle of friction mobilised was close to the critical state value for loose sands and close to those of peak values due to dilation for dense sands. The vertical load increased, though at a lower rate than during initial penetration, after large plastic displacements occurred. A hardening law formulation including this observed behaviour is suggested. In sand the installation of caissons by suction showed a drastic reduction in the net vertical load required to penetrate the caisson into the ground compared with that required to install caissons by pushing. This occurred due to the hydraulic gradients created by the suction. The theoretical formulations of the yield surface and flow rule were calibrated from the results of moment loading tests under low constant vertical loads. The fact that caissons exhibit moment capacity under tension loads was considered in the yield surface formulation. Results from symmetric and non symmetric cyclic moment loading tests showed that Masing’s rules were obeyed. Fully drained conditions, partially drained and undrained conditions were studied. Caisson rotation velocities scaled in the laboratory to represent those in the field induced undrained response for relevant periods of wave loading, a wide range of seabed permeabilities and prototype caisson dimensions. Under undrained conditions and low constant vertical loads the moment capacity of suction caissons was very small. Under partially drained conditions the moment capacity decreased with the increase of excess pore pressure. In clay, vertical cyclic loading around a mean vertical load of zero showed that in the short term the negative excess pore pressures generated during suction installation reduced vertical displacements. The yield surface and the flow rule were determined from moment swipe and constant vertical load tests. The moment capacity was found to depend on the ratio between the preload Vo and the ultimate bearing capacity Vu. Gapping response was observed during cyclic moment loading tests, but starting at smaller normalised rotations than in the field. The hysteresis loop shape obtained during gapping cannot be reproduced by means of the Masing’s rules.

Within the existing available mix of numerical and analytical thermal analysis options, lumped parameter thermal modelling is selected as the operational backbone to develop an improved novel synchronous generator thermal modelling package. The objective is for the creation of a user friendly quick feedback tool, which can serve as a means to make quick machine design thermal calculations and answer customer queries quickly and reliably. Furthermore, thermally improved generator designs will allow for inevitable operational losses to be channelled away from the machine more efficiently. As a result, machine component temperatures will be reduced, allowing lower generator thermal ratings. The end result will be smaller, longer lasting, more efficient generators, with the ability to be adapted with greater ease to particular applications. With the contribution of selected numerical analysis techniques, mainly finite element analysis for the distribution of iron losses, the MySolver thermal modelling package is developed and presented in this thesis. It is this combination of numerical and analytical tools that improves synchronous generator thermal modelling accuracy, but ultimately it is the lumped parameter nature of the thermal models developed that makes MySolver succeed as a reliable quick feedback electrical machine thermal design tool, validated using experimental results for a wide range of operating conditions. The initial part of the thesis analyses the electrical machine thermal modelling techniques available today, indicating advantages and disadvantages associated with each one, and providing a rationale for the selection of lumped parameter modelling to be used by MySolver. The development of the synchronous generator lumped parameter thermal models is detailed, with examples on its construction presented. Subsequently, finite element analysis is utilised to predict the distribution of machine iron losses across the rotor and stator laminations, with the findings applied to MySolver. Furthermore, a study is performed into the lumped parameter discretisation level needed to effectively represent machine windings. MySolver is experimentally verified using experimental data from a fully instrumented synchronous generator and this data is also used to obtain further insight into the temperature distribution within the generator. In the final part results are evaluated and the use of MySolver for modelling and optimising electrical machines is discussed. Finally, appropriate conclusions on the work presented are drawn.

Heat management is an essential part of combustor design, as operating temperatures within the combustor generally exceed safe working temperatures of the materials employed in its construction. Two principal methods used to manage this heat are impingement and film cooling. Impingement heat transfer refers to jets of impinging fluid delivered by orifices integrated into internal structures in order to remove undesired heat. This mode of heat transfer has a relatively high effectiveness, making it an attractive method of heat management. As such, a considerable number of studies have been done on the subject providing a substantial body of useful knowledge. However, there are innovative cooling configurations being used in gas turbines which generate compressibility and temperature ratio effects on heat transfer which are currently unexplored. Presented here are data showing that these effects have a significant impact on heat transfer and new correlations are presented to account for temperature ratio and Mach number effects for a range of conditions. These findings are significant and can be applied to impinging flows in other areas of a gas turbine engine such as turbine blades and vanes. Film cooling refers to the injection of coolant onto a surface through an array of sharply angled holes. This is done in a manner that allows the coolant to remain close to the surface where it provides an insulating layer between the hot gas freestream and the cooler surface. In order to improve turbine efficiency, research efforts in film cooling are directed at reducing film cooling flow without decreasing turbine inlet temperatures. Both impingement cooling and film cooling are heavily utilized in combustor liners. Frequently, cooling air first impinges against the back side of the liner, then the spent impingement fluid passes through film cooling holes. This arrangement combines the convective heat transfer of the impinging jets convection as the coolant passes through the film cooling holes and the benefits that come from having a thin film of cool air between the combustor wall and the combustion products. In order to improve the understanding of internal cooling in gas turbine engines, the influence of previously unexplored physical parameters such as compressible flow effects and temperature ratio in impingement flows and variable blowing ratio in a film cooling array must be examined. Prior to this work, there existed in the available literature only an extremely limited exploration of compressibility effects in impingement heat transfer and the results of separately examining the effects of Mach number and Reynolds number. The film cooling literature provides no information for a full array of film cooling holes along a contraction at high blowing ratios. Exploring these effects and conditions adds to the body of available data and allows the validation of numerical predictions.

Les mécanismes chimiques détaillés de combustion des carburants à basse température font intervenir un nombre important d'espèces et de réactions. Les logiciels de génération automatique permettent de faire face à cette complexité. Ces logiciels font appel à des corrélations permettant de prédire les propriétés thermodynamiques (enthalpies de formation, entropies et capacités calorifiques) et cinétiques (constantes de vitesse) associées aux espèces et aux réactions. Ces corrélations reposent cependant, généralement, sur un nombre limité de données de référence. Dans ce travail de thèse, nous avons utilisé une méthode faisant appel à la chimie quantique pour développer de nouvelles corrélations pour le logiciel de génération automatique EXGAS. En ce qui concerne les données thermodynamiques, des groupes de Benson associés aux fonctions hydroxyle et hydroperoxyle ont été évalués, ainsi que des énergies de liaison C-H, et O-H de fonctions hydroxyle et hydroperoxyle. En ce qui concerne les données cinétiques, nous nous sommes plus particulièrement intéressés aux réactions d'isomérisation des radicaux alkylperoxyles et hydroxyalkylperoxyles, ainsi qu'aux réactions de formation d'éthers cycliques. Nous avons également étudié l'impact de certaines règles de globalisation et introduit de nouvelles réactions pour rendre compte de la formation de produits de combustion jusqu'ici négligés ou sommairement prédits par les modèles. Les résultats obtenus ont été introduits dans des mécanismes chimiques détaillés générés par EXGAS. Ces mécanismes ont servi de base pour réaliser des simulations de la combustion du propane et du n-butane à basse température. Les résultats de ces simulations ont été comparés à des résultats expérimentaux récents afin de valider les calculs effectués. Les résultats des simulations ont montré que la prise en compte des nouvelles corrélations ainsi que la modification des règles de globalisation dans les mécanismes permettaient d'améliorer la prédiction de certains polluants mineurs pouvant avoir un impact sanitaire et environnemental majeur / Detailed chemical kinetic models for the low-temperature combustion of fuels involve a large number of species and reactions. Automatic generation of kinetic mechanisms is a powerful tool to deal with this complexity. These softwares are based on correlations that predict thermodynamic (enthalpies of formation, entropies and heat capacities) and kinetic (rate constants) properties associated with species and reactions. However, these correlations are generally based on a limited number of reference data. In this work, we used a method involving quantum chemistry to develop new correlations for EXGAS, a software for the automatic generation of kinetic mechanisms. For thermodynamic data, new Benson groups associated with hydroxyl and hydroperoxyl functions were evaluated. Bond dissociation energies of C-H bonds and O-H bonds of these groups were also evaluated. For the kinetic data, we focused our study on the isomerization reactions of alkylperoxyl and hydroxyalkylperoxyl radicals, and on the reactions of formation of cyclic ethers. We also studied the impact of some rules of globalization and introduced new reactions to account for the formation of minor combustion products usualy neglected or imperfectly predicted by the current models. The results obtained have been introduced into detailed chemical mechanisms generated by EXGAS. These mechanisms were used to simulate the combustion of propane and n-butane at low temperatures. The results of these simulations were compared with recent experimental results to validate the calculations. The simulations showed that taking into account the new correlations and the modifications of the rules of globalization in the mechanisms improved the prediction of some minor pollutants that can have major health and environmental impacts

A new quasi-dimensional, multi-zone model has been developed to describe the combustion processes occurring inside a dual fuel engine. A dual fuel engine is a compression ignition engine in which a homogeneous lean premixed charge of gaseous fuel and air is ignited by a pilot fuel spray. The atomisation and preparation of the pilot leads to the formation of multiple ignition centres from which turbulent flame fronts develop. The energy release in a dual fuel engine is therefore a combination of that from the combustion of the pilot fuel spray and lean premixed charge. Hence, the dual fuel combustion process is complex, combining elements of both conventional spark and compression ignition engines. The dual fuel engine is beneficial as it can achieve significant reductions in emissions of carbon dioxide (CO2), as well as reducing emissions of oxides of nitrogen (NOx) and particulate matter (PM).

Governments across the world are implementing legislation for ever more strict limits for vehicle emissions; combined with customer expectations for growing levels of performance and equipment, automotive manufacturers face a significant challenge. With the aim of meeting this challenge, downsizing is an established trend in passenger car engine development. However, since downsizing is commonly achieved through pressure charging (turbocharging, for example), the associated benefits in improved fuel economy and emissions are often obtained at the expense of engine dynamic response, and, consequently, vehicle driveability. This thesis presents predominantly simulation-based research into a novel combined charging system comprising a conventional turbocharger used in conjunction with a declutchable supercharger driven through a CVT. An initial investigation using this system in place of a variable geometry turbocharger on an already downsized passenger car diesel engine demonstrated greatly increased low speed torque as well as improved dynamic response. A downsizing project that involved replacing a naturally aspirated gasoline engine with a highly boosted engine with 40% of the original displacement formed the basis for more extensive investigations. Although it was unable to produce the low speed transient response of the naturally aspirated engine, in tip-in tests the CVT-supercharger system was shown to achieve the target torque much quicker than an equivalent system with a fixed supercharger drive ratio. However, balancing this with good fuel efficiency for the initial part load period was a complex trade-off. In vehicle acceleration simulations the CVT-supercharger system did not outperform the fixed drive ratio configuration, but on the CVT system the boost limit was reached at an early stage during the transients. Thus there may be potential to include an ‘over-boost’ facility, allowing boost pressure to temporarily exceed normal steady state limits in order to improve transient performance and bring it closer to that of the baseline vehicle. It is suggested that the CVT-supercharger provides the best flexibility for calibration and compromise between performance and fuel efficiency, perhaps incorporating different user-selectable modes (such as ‘economy’ and ‘sport’ modes).

The automated testing of internal combustion engines is a field of considerable importance. This thesis describes a novel area in the form of dynamic testing. The investigation represents an original approach to the problem with which the author believes he has developed a new concept in engine testing. The resulting information, combined with an appreciation of the latest developments in automation equipment technology, has lead to a review of the requirements of a generalised engine test system together with an outline of the way in which it could be implemented. The automated engine test beds used during the work are described. The conventional methods of testing internal combustion engines are reviewed and a generalised approach to automating them proposed. This then leads to the suggestion of a new method using dynamic testing techniques specially evolved in the course of the work. On the basis of this the implementation of a dynamic full-load power curve as a replacement for its steady state equivalent was pursued. The second major use of dynamic techniques is for exhaust emission cycles. Both dynamic (USEPA Smoke Cycle) and steady-state (USEPA 13 Mode Cycle) cycles were performed. In the case of the former, outer digital loop techniques were used to improve control response. In performing the above work, use was made of both analog and digital simulation techniques for development purposes. This work was also extended by the development of a simulation of a material handling system to enable the control and optimisation of a production test facility to be studied. The testing methods associated with automated fault diagnosis are also analysed. On the basis of the above work an engine test system task analysis was generated and this new concept used to plan a microprocessor based engine test automation scheme.

The continuing requirement for computational processing power, multi-functional devices and component miniaturization have emphasised the need for thermal management systems able to maintain the temperature at safe operating condition. The thermal management industry is constantly seeking for new cutting edge, efficient, cost effective heat transfer enhancement technologies. The aim of this study is to utilize the electron beam treatment for the improvement of the heat transfer area in liquid cooled plates and experimentally evaluate the performance. Considering the complexity of the technology, this thesis focuses on the design and production of electron beam enhanced test samples, construction of the test facility, testing procedure and evaluation of thermal and hydraulic characteristics. In particular, the current research presented in this thesis contains a number of challenging and cutting edge technological developments that include: (1) an overview of the semiconductor industry, cooling requirements, the market of thermal management systems, (2) an integral literature review of pin-fin enhancement technology, (3) design and fabrication of the electron beam enhanced test samples, (4) upgrade and construction of the experimental test rig and the development of the test procedure, (5) reduction of the experimental data and analysis to evaluate thermal and hydraulic performance. The experimental results show that the capability of the electron beam treatment to improve the thermal efficiency of current untreated liquid cooled plates is approximately three times. The highest heat transfer rate was observed for the sample S3; this is attributed to the irregularities of the enhanced structure, which improves the heat transfer area, mixing, and disturbs the thermal and velocity boundary layers. Enhancement of heat transfer for all three samples was characterised by an increase of pressure drop. The electron beam enhancement technique is a rapid process with zero material waste and cost effective. It allows thermal management systems to be produced smaller and faster, reduce material usage, without compromising safety, labour cost or the environment.

In this thesis, the experimental test facilities consisted of a well instrumented live Ford 2.0 litre turbocharged diesel engine connected to a specially made exhaust can, which contained a diesel oxidation catalyst (DOC). Experiments were performed on DOCs, which were specially prepared by Johnson Matthey, and had thermocouples mounted in their walls to measure axial temperature profiles. These DOCs consisted of a Pt catalyst dispersed in an alumina washcoat on a cordierite monolith supports, and were representative of a commercial application. Experiments were performed on Full-scale DOCs (o.d. = 106 mm, length = 114 mm), and also on Thin-slice DOCs (length = 5 and 10 mm), which generate some interesting data, and enabled a technique that is normally only used in laboratory bench-top experiments to be applied to a live engine. A number of different methodologies were developed based on (a) the operation of the engine at pseudo-steady-state operating conditions, and (b) transient experiments (e.g. a pulse of CO was injected into the exhaust gas just before the DOC). For example, it was shown how experiments on a live engine can be used to explore: (a) the hysteresis between light-off and extinction curves, (b) how catalyst temperature rise during warm-up of a DOC, (c) the promotion effect that hydrogen has on the conversion of CO, (d) the extent of competition for active catalytic sites, e.g. between CO, THCs, propane or hydrogen. The main findings are: (a) the hysteresis between light-off and extinction curves are mainly caused by CO inhibition, (b) the promotion effect of hydrogen on CO oxidation is largely attributed to thermal effect, (c) LHHW form rate expression is not adequate for catalytic converter modelling under transient conditions, (d) the competition for active catalytic sites is not apparent at the test conditions performed in this thesis. Moreover, a number of case studies were also used to illustrate how the experimental results/techniques developed in this thesis, may be used to support modelling studies. iii