Diesel Particulate Filter (DPF) is believed to be one of the most effective methods and provides an efficient system that traps more than 90% of PM. However, the soot accumulated within the filter requires a regeneration process to recover its performance. Thus, the high oxidation ability of NO-NO₂ increases the interest of applying it in the low temperature regeneration process. The intention of this thesis is to investigate several possibilities of on-board NO-NO₂ oxidation methods for increasing the NO₂/NO_x ratio in the exhaust gas. These possible oxidation routes incorporate the in-cylinder to the exhaust gas treatment processes. A wide range of operated temperatures are managed by the application of the non-thermal plasma oxidation (NTP) for low temperatures, catalytic oxidation for moderated temperatures and thermal oxidation for high temperatures studied. The in-cylinder NO oxidation was significantly improved by adding H₂ or the reformed EGR (REGR) to the combustion. The remaining H₂ after the combustion also contributes to the downstream HC-SCR which in turn promotes the NO oxidation. The thermal and NTP methods in the exhaust treatment cannot adequately achieve a satisfactory NO oxidation result under a single occupied condition. The propane (C₃H₈) addition may potentially create useful radicals (HO₂, RO₂) within the system and convert a large portion of NO into NO₂.

The overall aim of the project/research was to develop finite element modelling/process simulation capability to predict workpiece surface integrity following machining of advanced aerospace alloys. The modelling work employed the general-purpose commercial finite element (FE) software ABAQUS, due to its robust solver for handling complex, dynamic non-linear problems as well as the facility to define custom algorithms/subroutines. Both 2D and 3D fully coupled thermo-mechanical FE models were formulated to simulate the orthogonal turning of Ti-6Al-4V titanium alloy and Inconel 718 nickel based superalloy. The performance of various material models and associated damage criteria were assessed, with high strain rate (up to ~ 6000 s\(^-\)\(^1\)) / temperature (up to ~ 850°C) flow stress data for Inconel 718 obtained from compression tests using SHPB and Gleeble systems. In addition to evaluating the influence of operating conditions on response measures such as cutting forces, temperatures and chip morphology, the FE models were extended to enable prediction of grain size distribution due to dynamic recrystallisation (DRX) of workpiece microstructure following machining. This was accomplished by developing a VUMAT user customised subroutine that included material constitutive modelling, damage initiation/propagation as well as a novel material model to predict workpiece grain refinement due to DRX.

Adsorption cooling systems are considered to be an important alternative to conventional heating and cooling systems, however at present it has had limited commercial applications. This is because of the low thermal heat transfer during its operations cycle from heat exchanger to adsorbent packing. The main objective of this study is the design and CFD simulation of a new compact copper wire woven fins heat exchanger and silica gel adsorbent bed used as part of an adsorption cooling system. This type of heat exchanger has a large surface area because of the wire woven fins design but can still be design as a small compact heat exchanger. It is proposed that this will help improve the coefficient of performance (COP) of the cycle and improve the heat transfer rate in the system.

Selective Laser Melting (SLM) as a method of netshape manufacture is of growing interest within the aerospace industry. There is currently a lack of understanding of the influence of process variables on the integrity and properties of the as fabricated material. The research presented investigates the SLM fabrication of three nickel superalloys: Primarily CM247LC and CMSX486/IN625 as secondary alloys. CM247LC is Ni-base superalloy hardenable by the precipitation of the coherent \(\gamma\)'phase. It presents a particular challenge due to weld-crack susceptibility. This research aims to establish a processing route for CM247LC components via SLM: Parametric studies are presented to quantitatively assess the cracking behaviour based on microstructural observations; Hot Isostatic Pressing HIPping) has been investigated as a retro-fix solution to cracking; Electron BackScatter Diffraction (EBSD), MicroCT Tomography and microscopy have been used to characterise the SLM microstructure. The \(\gamma\)' evolution through the manufacturing stages (SLM & Heat Treatment) has been examined. Mechanical testing creep/tensile) was performed for comparison against cast material. Research was extended to two additional alloys: CMSX486 and IN625. Statistical design of experiments methodology was used to rapidly establish process parameters for these two alloys and assess them by mechanical testing. In conclusion a processing route capable of yielding fully dense material with a satisfactory \(\gamma\)' structure is presented; however, it involves significant post-fabrication processing which reduces the attractiveness of SLM. Further research is suggested, specifically into modelling and thermal measurement of SLM

This Engineering Doctorate project aimed to study the effects of varying flowrates on the flow dynamics of carbon dioxide within a pipeline. The researched utilised the software gCCS to simulate three different transport system. The first system looked at the effects of transporting pure carbon dioxide in both the supercritical phase and the sub-cooled liquid phase. The outputs from the model showed that when the inlet flowrate is decreased, the outlet flowrate responds in three distinct phases. The second system compared the effects of three different impurities; hydrogen, nitrogen and oxygen, on the flow response when the inlet flowrate is decreased. It was found that all three impurities caused an increase in the offset between the inlet and outlet flowrate. The third system looked at how multiple sources of carbon dioxide effect the flowrate within the main trunk pipeline. It was found that multiple sources of carbon dioxide do not affect the flow of CO2 within the pipeline beyond that of the base case. The final part of the research compared data from the Shell QUEST pipeline to the model. This showed the model was able to predict the flowrate and pressure of the carbon dioxide with good accuracy.

The gear components in the aero-engine transmission system are subjected to very high stresses during service at elevated temperatures. Due to requirements of increasing power take-off and weight reduction further improvements in the high-strength gear steel are needed. The aim of this project was to design a new steel composition to give an increase in the core strength by 10 % compared to the currently used BS S 156 high-strength gear steel and increase the material capability to withstand higher operating temperatures of up to 300 oc. In addition to this, it was required that the new steel should also have similar or higher ductility, fracture and impact toughness, fatigue and wear resistance to the current steel, with minimal changes being allowed to the current heat treatment schedule. A final requirement was that the design process should also consider minimising the cost of the new steel composition through reducing the use of expensive alloying elements.

The emission performance of fuels and their blends in modern combustion systems have been studied with the purpose of reducing regulated and unregulated emissions, understanding of exhaust products of fuels such as gasoline, ethanol and 2,5-dimethylfuran and comparison of results. A quantitative analysis of individual hydrocarbon species from exhaust emissions of these three fuels were carried out with direct injects spark ignition (DISI) single cylinder engine. The analysis of hydrocarbon species were obtained using gas chromatography-mass spectrometry (GCMS) connected on-line to SI engine. During this project, novel works have been done including the set up of on-line exhaust emission measurement device for detection and quantification of individual volatile hydrocarbons. Setting of a reliable gas chromatography mass spectrometry measurement system required definition and development of a precise method. Lubricity characteristics of biofuels and gasoline were investigated using High Frequency Reciprocating Rig (HFRR). Results showed great enhancing lubricity characteristics of biofuels when added to conventional gasoline. 2,5-dimenthylfuran was found to be the best among the fuels used, addition of this fuel to gasoline also showed better result compared with ethanol addition.

In this work, a CFD model was developed to simulate the flow and phase-change process inside the Two-Phase Closed Thermosyphon (TPCT). This was carried out to investigate the effect of fill ratio and inclination angle on the thermal performance of the TPCT, and to visualise the phase change characteristics under the influence of the inclination and different fill ratios. Also, the surface wettability in terms of the contact angle was investigated to report their effect on the thermal characteristics of the TPCT and to visualise the phase-change characteristics inside the TPCT for different contact angles using Fluent Ansys. Furthermore, the effect of different parameters on the geyser boiling in the TPCT was investigated experimentally. Consequently, the influence of geyser effect on the TPCT thermal characteristics was examined under the effect of various liquid charges and inclination angles at a broad range of heat inputs. Finally, advanced manufacturing technique using wire Electrical Discharge Machining (EDM) was employed to introduce a surface roughness in the TPCT internal wall, thereby enhancing the thermal performance of the TPCT. This was achieved by comparing its thermal performance with a plain TPCT at two different initial sub-atmospheric pressures (3 and 30 kPa) and different heat loads.

The tests were conducted on a 2.2 L, four-cylinder Ford Puma engine running on a Premixed Compression Ignition (PCI) mode and at steady state. Hot EGR was introduced for fuels, G75 and naphtha and it significantly reduced the total particle number and mass concentrations by about 99% and the mean diameter to a smaller size ~ 10 nm compared to diesel fuel. Single injection reduced the total particle numbers’ concentration and smoke of both fuels G75 and naphtha by about 99%. Also, the total carbon (TC) was reduced by more than 54% for G75 and naphtha fuels compared to diesel fuel. The double injection strategy was flexible than the single injection. It reduced the total particle numbers’ concentration and smoke of G75 and naphtha fuels by about 99.80% at low and medium loads, also the total concentration of PAHs was reduced by more than 90% compared to single injected diesel fuel. For G75 fuel, double injection reduced the total concentration of alkanes by 60%, while single injection reduced the total concentration of cycloalkanes by 54% compared to other fuels.

New Concentrated Optical Water Filter (COWF) for Photovoltaic (PV) applications is investigated. The COWF is placed in front of the PV module in order to reduce the thermal load on the PV. The COWF acts as a spectrum splitter to absorb the unwanted radiation and convert it to heat, and allow the useful radiation to reach the PV. The COWF consists of two parts; Optical Water Filter (OWF) and V-trough Solar Concentrator (VTSC). The OWF consists of two glass panels with specific gab filled with water which flows carrying away the heat and preventing it from reaching the PV. However, the disadvantage of using the OWF with PV is some reduction in the electrical power output of the PV due to optical losses. Therefore, VTSCs are developed to be integrated with OWF to overcome the optical losses. The VTSC consists of two reflectors placed as a (V) letter in front of the OWF in order to increase the solar radiation received by the PV to overcome the optical losses by the OWF. Overall, it can be concluded that COWF can enhance the electrical performance of the PV and reduce the PV temperature simultaneously relative to the PV module without COWF.