Lubricant degradation mechanisms in the 4-stroke heavy duty diesel engines of RNLI lifeboats were investigated. These mechanisms lead to the increased wear of main engine components, such as cylinder liners. The lifeboat application is distinct from the other marine applications from an engine lubrication perspective, since it involves infrequent engine running conditions and is often subjected to either under or over engine maintenance due to the unpredictable usage of lifeboats. This research has demonstrated the key lubricant properties which were affected by the lifeboat operations. Analysis of used lubricants was conducted such as Wear Debris Analysis (Analytical Ferrography) to identify the wear mechanism of affected tribological contacts and Nuclear Magnetic Resonance (NMR) analysis to analyse the trend in reduced effectiveness of antiwear additives. Other standard lubricant analysis technique were also performed to supplement the information about the lubricant condition. The experimental test rig involved the modification of a high frequency reciprocating tribometer (Plint TE77) to simulate piston ring and cylinder liner configuration. Boundary lubrication conditions that exist near the top dead centre region of cylinder liner were simulated in order to evaluate the tribological performance of lubricant additives. Also real-time condition monitoring of engine lubricant samples was carried out using a commercially available on-line sensing system. The obtained results from oil sensor were sufficiently promising to conduct engine level tests in lifeboat to monitor lubricant performance in real-time and build the system as part of the planned maintenance strategies of the RNLI. The work also involved recovering the tribological performance of used engine lubricants for further use at the end of their service life. Ionic Liquids (ILs) were tested as performance improving additives in used engine lubricants at engine start and running conditions using the modified Plint TE77 experimental test setup. Additional tests were conducted with different fully-formulated and mineral base oils with ILs as additives. Post-test surface analysis for wear mechanism and surface chemistry analysis of boundary antiwear films were performed to relate the chemical composition of films with its tribological performance. Obtained results demonstrated significant improvement in tribological performance of used engine lubricants. Also interference between Phosphonium ILs and existing additives in engine oils was noted. ILs effectively contributed to the boundary film formation when already present additives (such as ZDDP) are substantially depleted as seen in the case of used engine oil. The extension of service life of used engine oils can be achieved and has potential of significant savings in terms of fuel economy, engine reliability and by reduced oil consumption and drainage into the environment.

There is a concerted world wide effort to limit greenhouse gases into the atmosphere. Civil shipping accounts for a 3 % proportion of greenhouse gas emissions and to combat this problem, nuclear power is proposed as an alternative energy source. This thesis set out to evaluate the use of a civil marine nuclear reactor for commercial shipping purposes. A review was carried out to determine past uses of civil marine nuclear reactors to assist specification of the criteria for a civil ship reactor e.g. reactor type, operating conditions. The refuelling period of such ships was understood as an issue for commercial success and so having fuel in the reactor for periods of 15 years was determined to be a key goal, as well as keeping the fissile enrichment of the fuel low. Computational simulation of the thermo-mechanical performance on fuel rods under expected operating conditions for a civil marine reactor were conducted. Higher thermal efficiency in the fuel rods was determined to be key in achieving long refuelling periods. Fabrication of simulant fuel cermets was undertaken with spark plasma sintering to produce simulant cermet fuel pellets with improved thermal conductivity and was evaluated to be an efficient cermet production route. This was achieved with YSZ as a simulant for UO2 fuel, with metallic Mo and W to produce stable cermets at varying metallic loading. The thermal conductivity values were found to increase by a factor of 2-3 with up to 30 % metallic loading. The final aspect of this thesis focused on finite element simulation, studying the shape of metallic loading inside a cermet to determine a suitable layout to provide the greatest thermal transfer with several candidate geometries determined to be appropriately suitable.

Electric propulsion is a growing market in the marine sector, this growth is mainly driven by commercial shipping due to space and economy benefits. However military applications are watching developments closely due to the inherently quiet nature of electric propulsion when compared to traditional methods. Therefore Rolls-Royce fine Electrical Systems are looking for a mechanism of providing quiet operations on a standard marine drive. The work undertaken within the thesis has shown the benefits and limitations of this highly data intensive torque table based controller.

No description available.

With the increased understanding of the physical processes of the large 2-stroke marine engine and the corresponding numerical models as turbulence, injection, evaporation and chemical combustion, it has become realisable to investigate the whole working processes using Computational Fluid Dynamics (CFD). However, CFD itself needs to be validated to produce reliable results. The focus of this thesis is on the CFD validation of the large 2-stroke marine diesel engine working processes. The turbulence models and the wall functions in the CFD solver were firstly tested using two basic 2D cases to obtain performance results in the modelling of turbulence flow and heat transferring near the wall. It was concluded that the RNG and the realisable Ҡ-Ɛ turbulence models predict the same best flow field and non-equilibrium wall function produces the best heat transfer results. Following this, the spray breakup models were evaluated through the constant volume spray chamber test. The Stochastic Secondary Droplet (SSD) model was verified as the best one for its generality and accuracy. During this process, the appropriate mesh for droplet calculation using Euler-Lagrange approach was determined. Based on the ontained conclusions, the computation model of a large 2-stroke marine diesel engine MAN B&W S60MC-C6 was generated, with the proven best models, the RNG Ҡ-Ɛ turbulence model, the Non-Equilibrium wall function and the SSD breakup models. In addition, different combustion models including the Finite Rate/Eddy Dissipation (FRED), the Non-Premixed Equilibrium, the Non-Premixed Steady Flamelet and the Non-Premixed Unsteady Flamelet Diesel were investigated at four engine loads (25%, 50%, 75% and 100% Maximum Continuous Revolution (MCR)). The obtained in-cylinder pressure traces were compared with the test shop data. It was proven that the Non-Premixed Equilibrium combustion model presented the best prediction performance at four loads. The derived conclusions can be used as guidelines for CFD simulations of the large 2-stroke marine diesel engines working processes. It also provides the starting point for engine optimisation to increase engine efficiency and reduce pollutant emissions.

The answers to the question, “How might the roughness of coatings and biofouling be related to full-scale ship resistance and powering?” were sought in this research, and novel contributions were made to the state-of-the-art knowledge. The current techniques used for predicting the roughness effects of marine coatings and biofouling on the resistance of full-scale ships rely on assumptions from similarity law scaling and boundary layer theory. Although this is a reasonable method, it may be difficult for less experienced users to carry out such an analysis since similarity law scaling includes several numerical procedures which may cause numerical errors and requires deep knowledge of the subject. It would also be beneficial to propose alternative methods with which to accurately predict these effects using fully-nonlinear Computational Fluid Dynamics (CFD) models, since current technological advances offer computational power which can be utilised to perform simulations based on Reynolds-Averaged Navier-Stokes (RANS) approaches. This work mainly aims to model the roughness effects of marine coatings and biofouling on ship resistance and powering, and to develop and propose alternative models for this purpose. Firstly, drag characterisation of several marine coatings, including the novel paints developed within the EU FP7 FOUL-X-SPEL Project, as well as control surfaces, was made through towing tests of flat plates coated with such coatings. An in-house code based on the similarity law scaling was then developed. This was used to assess the roughness effects of different marine coatings, including FOUL-X-SPEL Paints, and different fouling conditions on the frictional resistances of flat plates of ship lengths. Added resistance diagrams were generated using these predictions. Following this, two separate CFD models were developed and proposed for the prediction of the roughness effects of marine coatings and biofouling using flat plates of both model-scale and full-scale. These models were validated against an experiment and compared with the similarity law scaling, respectively. Afterwards, unsteady RANS CFD simulations of the roughness effects of marine coatings and biofouling on the full-scale KCS hull appended with a rudder were performed, using the roughness models proposed earlier, in order to arrive at a final conclusion. Finally, some discussions and conclusions on the outcomes of the work performed within this thesis are presented. This author believes that this study has shown the applicability of the CFD-based method to investigate the roughness effects of marine coatings and biofouling on ship frictional resistance. The CFD methods and added resistance diagrams proposed in this thesis stand as practical prediction methods for both academia and industry.

The design of green ships has received significant attention with the goal of reducing the negative environmental impacts of shipping and to comply with the more stringent environmental regulations. Therefore, in 2009 the International Maritime Organisation (IMO) published the Energy Efficiency Design Index (EEDI) measures to be adopted by new ships to reduce the Greenhouse Gases (GHG). Hybrid electric power and propulsion is one of the EEDI measures and fuel cell technologies are considered as a candidate to be used due to their high efficiency, lower emissions, lower maintenance, and quiet operation. This project aims to investigate the use of hybrid propulsion systems for marine propulsion which utilise fuel cells as a main source of power and the effect of energy management on the performance of these systems through voyage simulation. In order to assess the effectiveness of fuel cells as a source of power for ship propulsion systems, the development of a time-domain three degree of freedom total ship system simulator using MATLAB/Simulink is completed. Different components of the ship, including its propulsion system, and the ship's interaction with the surrounding environment are mathematically modelled. Considered power sources in the thesis include conventional two and four-stroke diesel engines, fuel cells and batteries to enable the comparison between conventional and hybrid fuel cell power trains. The verification and validation of the developed ship system simulator are also conducted using numerical, experimental and real ship operational data. The thesis demonstrates the use of the developed total ship system simulator in proposing a hybrid fuel cell/battery propulsion system for a domestic ferry. The results indicate that the hybrid fuel cell system has less weight and requires less space than the conventional diesel system. However, the hybrid fuel cell system's associated costs are still higher than diesel propulsion system. For hybrid fuel cell systems, the design of a suitable energy management strategy is essential in order to handle properly the required power split between the fuel cell and the battery systems. Therefore, the developed ship system simulator is also used to study and compare the most common energy management strategies. An improvement to the classical proportional-integral controller based strategy is presented in this thesis. This improvement results in minimizing the fuel cell operational stress and hydrogen consumption. Alongside this work, a novel multi-scheme energy management strategy with a main objective of reducing the total consumed energy is also developed for the world's first fuel cell passenger ship.

Cavitation erosion process is a very complex phenomenon depending not only on the type and unsteadiness of cavitation, but also the response of the propeller and rudder materials to the cavitation energy imparted upon. It is highly destructive in nature and can cause severe loss in the performance of the ships that may eventually lead to frequent dry dockings, inspections and preventive maintenance or replacement of the damaged parts, resulting in a rather expensive maintenance. The aim of this PhD project is to look at different aspects in characterising the materials generally used for manufacturing the ship propellers and rudders based on their resistance to cavitation erosion. It aims to understand the cavitation phenomena simulated by the ultrasonic vibratory probe device on various ship propeller material samples. Several ultrasonic vibratory cavitation tests were conducted for cavitation erosion, pure corrosion and combined cavitation erosion-corrosion on the two most common metallic propeller materials, Duplex Stainless Steel (DSS) and Nickel Aluminium Bronze (NAB), especially comprising of well-formed oxide films in different conditions. The investigation of the synergistic effect existing between the cavitation erosion and corrosion was carried out with the help of steady mass loss over a period of time and in-situ electrochemical measurements of corrosion. Alicona was employed for surface analyses, and comparisons between gravimetric and volumetric/optical loss measurements were obtained using precision weighing machine and Alicona respectively. Ag/AgCl reference electrode was used for in-situ electrochemical experiments done on both the sample materials kept at open circuit potential, and electrochemical impedance spectroscopy to study the corrosion behaviour during the experimental tests. In order to understand the combined synergistic effects of cavitation erosion and corrosion in seawater five different methods were employed to measure and quantify synergism. The experiments were conducted using an ultrasonic vibratory horn functioning at 19.5 kHz frequency and 80 μm ± 0.2 μm peak-to-peak amplitude. The test methods used to obtain the synergy included gravimetric mass loss technique, volumetric mass loss and mean depth of penetration rate methods, and polarization technique. Scanning electron microscopy was used to analyse microstructural characteristics of the cavitated sample surfaces, as well as the transverse-sections of the surface features. The materials were subjected to pure erosion, pure corrosion and the combined effect of erosion-corrosion in order to understand and measure the individual contributions of each aspect. The extensive experimental results obtained and the conclusions drawn have attempted to address the aim of the research, and meet all the objectives to the best effect. Synergism was found to have measurable impact on the cavitation erosion-corrosion of both NAB and DSS. NAB underwent selective phase attack, resulting in increased material removal especially in the presence of corrosive environment. Whereas, DSS was observed to undergo ductile failure in the cavitated zone in the form of extrusion of the austenite at the cavity boundary along with microcracks and cleavage facets that could be attributed to the austenite to martensite transformation by either high strain or high temperature generated during cavitation. The implications of immersing as-cast NAB in 3.5% NaCl solution for few months seemed to drastically change the synergy behaviour of the material. Whereas, DSS, having higher mechanical and corrosion property as compared to NAB seemed to give best outcome for cavitation erosioncorrosion.

In order to meet the IMO’s (International Maritime Organisation) target of 14% reduction of CO₂ emissions from marine activities by 2020, the application of Carbon Capture and Storage (CCS) on ships is considered as an effective way to mitigate the CO₂ emission while other low carbon shipping emission technologies are being developed. A comprehensive literature review of onshore CCS applications has indicated that current CCS technologies could not be implemented on-board directly due to the various limitations of ships, such as constraint space and system retrofit. In this thesis, a novel method of chemical CO₂ absorption and solidification for marine applications is analysed and presented. Technical feasibility and cost assessment of this method are carried out by comparison with the conventional method (liquefaction) for a case study ship. The thesis will also present results obtained from laboratory-scale experiments. Theoretical study and lab-scale experiments have shown that the proposed CO₂ absorption and solidification method is a promising, cost-effective and practicable method for CO₂ emissions reduction on ships. Carbon capture and storage is an excellent solution for reducing the greenhouse gas emissions from applications on shore. A novel method to absorb and solidify CO₂ from the exhaust gases on the ship is proposed and verified. CO₂ gas flow rate, the geometry of the absorption tanks and the concentration of the absorption solution are key factors that affect the reaction efficiency. The experimental results illustrate the impacts of these factors on CO₂ absorption efficiency. Meanwhile, the effects of these key factors on CO₂ absorption rates will also be presented in the CFD simulations of this thesis. Pressure distributions, the concentration of the solution and the velocity of both the gas and the solution during the different processes will be derived from the numerical simulations. The results of the simulations provide fundamental details for the design of a prototype demonstration system on-board a ship. In addition to the key factors discussed above, the effect of atmospheric temperature will be observed and analysed. With a comparison of experimental data and CFD simulation results, it will be demonstrated that the CFD simulations of the effects of CO₂ gas flow rate, the geometry of the absorption container and the concentration of the absorption solution on absorption rate have a good agreement with the experimental results. Optimised values of these factors are obtained from the comparisons and analyses. The numerical simulations will [sic] carried out to test the impact of phase temperature on absorption rate also indicate the optimal temperature for carrying out the absorption process. As the simulation results match with the experimental results, the simulation model developed is considered to be applicable for a case study ship practical system simulation. Geometry, fluid flow rate, temperature and some other parameters are adjusted to fit a practical system. At this stage, the practical system is designed and the most appropriate absorption process is selected. The designated system is modelled and simulated based on the simulation processes from the lab-scale experiments. The orthogonal design method is applied to optimise the system. Key parameters are varied within a reasonable range so that a large number of trials are initially needed to find the optimal one. With the orthogonal design method, the number of trials is reduced so that computing intensity is reduced and finally the optimised absorption system is derived. The volume required for the precipitation tanks, CaO and CaCO₃ storage tanks and the centrifuge separation are derived and the installation and positioning of these tanks, as well as the positioning of the whole system, will be presented. It is concluded that CCS for marine activities could enable ships to comply with various regional and international CO₂ emissions regulation whilst also maintaining the efficiency of waterborne transportation. The whole design process for the case study ship is presented here and could be applied as a guideline process for new design, analysis and installation.

This project is to investigate the velocity profile and turbulence intensity within a ship's propeller wash using a joint computational and experimental approach. Ship's propeller jet consists of two zones, the zone of flow establishment (ZFE) and the zone of established flow (ZEF). In these zones, the axial, tangential and radial components of velocity are predicted using computational fluid dynamics (CFD). The CFD predictions show the axial component of velocity is predominant in the propeller wash. This is followed by the tangential component of velocity, which contributes to rotation of the jet, arid the radial component of velocity, which contributes to the jet diffusion. Laser Doppler Anemometry (LDA) is employed to measure the velocity magnitudes within these two zones allowing the validation of the CFD predictions. The investigation suggests the most appropriate choice of the turbulence model, rotating model, discretisation scheme, computational geometry and the grid type to be used to simulate a ship's propeller wash. A comparison between the current experimental measurements and the earlier works are also presented.