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Advanced turbofan architectures with alternative fuels
No full textMourouzidis, Christos - Associate SupervisorAviation at present is required to reach net zero carbon emissions by 2050. An
effective method to reduce aviation’s carbon footprint with immediate effect is to
switch to alternative fuels. This thesis explores novel alternative fuels that could
be used for future civil aviation and investigates their impacts on turbofan design
to aid in research and development of future turbofan engines operating with
alternative fuels. Investigations have been conducted in a systematic manner by
adopting an appropriate methodology to answer the identified research
questions. The proposed novel alternative fuels for civil aviation consists of seven
fuels namely Hydrogen, Ammonia, Methane, DME, Butane, Butanol and Octane
with SAF as an additional drop in fuel.
The potential impacts and design opportunities for turbofan engines when
operating with the proposed alternative fuels is highlighted through a preliminary
turbofan design space exploration study. Maximum impacts in the design space
are observed for zero carbon fuels Hydrogen and Ammonia. They offer 3% and
6% ESFC benefits respectively against kerosene with up to 20K and 40K peak
cycle temperature reduction at take-off.
The potential impacts on turbofan engine size and weight when operated by
alternative fuels is brought to light through this research. Maximum impacts on
engine size, weight and temperature are observed for zero carbon fuels
Hydrogen and Ammonia. The maximum benefits in weight and take-off
temperatures are 20% and 164K respectively for Ammonia cycles whereas for
Hydrogen cycles, it is 6% and 64K respectively.
The potential role that aircraft mission range can play in affecting the turbofan
engines powered by alternative fuels is showcased in this thesis. Hydrogen SMR
and LR aircraft leads to BPR increment up to 31.7% and 61.5% respectively
considering a retrofitted style Hydrogen aircraft application..
The potential role of various fuel conditioning strategies and thermal power
requirements in affecting turbofan designs highlighted through this research work
indicates fuel conditioning to be a major design driver for future turbofan engines
operating with alternative fuels. For the investigated LR thrust class application,
Hydrogen, Methane and Ammonia requires up to 3 MW, 2.28 MW and 2.2 MW
of thermal power to condition the fuel respectively.
Finally, the thesis explores the feasibility of utilising Ammonia as a Hydrogen
carrier in aviation and highlights certain challenges at mission level and turbofan
design implications. For the investigated LR thrust class application, the amount
of thermal power required to crack Ammonia into Hydrogen for the Hydrogen
turbofan engines can be up to 25 MW which is interestingly an order of magnitude
higher than the fuel conditioning requirements of Hydrogen, Methane and
Ammonia.PhD in Aerospac
Analysis of active aerodynamics for high-performance vehicles
No full textThe pursuit of greater efficiency and performance drives advancements in the automotive
and motorsport industries, with active aerodynamics emerging as a promising approach
due to their ability to dynamically adapt aerodynamic characteristics to specific operating
conditions. However, their development presents challenges, including the need for
practical yet accurate simulation methodologies, a deeper understanding of vehicle aerodynamics
in dynamic conditions, and a comprehensive assessment of their performance
potential. This research addresses these challenges through interdependent studies. A
cost-effective Computational Fluid Dynamics (CFD) workflow is developed and validated
against experimental and high-fidelity simulation data, complemented by a structured
wind tunnel correlation process to ensure reliable aerodynamic predictions. Yaw
and cornering effects on flow field characteristics and aerodynamic performance are analysed
using wind tunnel experiments and CFD simulations. Finally, active aerodynamic
configurations, including 2D systems capable of modulating aerodynamic balance longitudinally
and laterally, are designed and examined using minimum lap time simulations to
assess performance gains, optimal control strategies, and dependencies on vehicle setup.
The CFD workflow demonstrates high predictive accuracy across various aerodynamic
conditions, with the structured correlation process improving experimental data interpretation
and validation. However, conditions critically dominated by highly unsteady
flow phenomena require higher-fidelity simulations. Yaw and cornering conditions induce
significant flow field alterations, including underbody interference, enhanced upper
surface flow acceleration, and asymmetric wake structures, leading to substantial downforce
and drag penalties. Active aerodynamic systems provide significant performance
benefits across diverse scenarios, with 2D systems consistently outperforming conventional
designs by prioritising aerodynamic loads on underloaded tyres to improve total
grip. Overall, this research advances numerical methodologies, deepens understanding of
vehicle aerodynamics in dynamic conditions, and demonstrates the performance potential
of various active aerodynamic designs. The work establishes a foundation for optimising
vehicle performance with active aerodynamic systems, supporting future research and
industry innovations in automotive and high-performance vehicle engineering.PhD in Transport System
Investigation of wire-based laser directed energy deposition (DED) process for high-resolution submillimetre features
No full textRodrigues Pardal, Goncalo - Associate SupervisorIn this thesis, the feasibility of manufacturing submillimetre-scale wall features using 250 W to 500 W and 1.00 kW to 2.79 kW laser power, from a 1.0 mm small beam to 1.5 mm – 3.0 mm large beams was investigated. The D-ratio correlates the beam diameter with wire diameter was introduced for deposition performance and wire position sensitivity discussion.
The study firstly reveals the possibility of fabricating defect-free, smooth surface appearance and submillimetre-scale wall features using 500 W of laser power with large laser beam diameters of 1.50 mm to 2.00 mm (D-ratio of 2.50 to 3.33) without the plume interference. It was found that using a larger beam size can enhance the chance of deposition success due to enough specific point energy applied, a relatively lower but even distribution of the power density, and less energy discrepancy projected on wire and substrate, as a result, increase in the possibility of deposition success.
This study also successfully applied 2.79 kW of high-level laser power and a large beam size of 3.00 mm (D-ratio of 5.00) to build the millimetre-scale wall features at a fast processing speed. It was found that fast processing speed, large laser beam size, and high-level laser power enable the chance of feeding more material into the melt pool, meanwhile, a larger D-ratio is needed for preventing the wire position sensitivity introduced back. A deposition rate of 400 g/h was achieved by using a 0.6 mm diameter wire and still exhibits the potential of fabricating submillimetre-scale wall features with the deposition rate potentially reaching 750 g/h, which is comparable to the conventional power-based laser DED process of 600 g/h.
Finally, the possibility of applying FLMIPs in the wire-based laser directed energy deposition regime was revealed, but the comprehensive feasibility of applying these parameters in the wire-based laser directed energy deposition regime needs to be further investigated.
These imply that wire-based laser DED process is capable of manufacturing submillimetre-scale features with good performance at relatively large beam
sizes and has the potential to achieve competitively high deposition rates in submillimetre-scale features to satisfy the rapid manufacturing requirements in the additive manufacturing regime.PhD in Manufacturin
Multi-point surrogate-based aerodynamic optimisation of a generic hypersonic waverider
No full textFor atmospheric flight at hypersonic speeds, waverider designs offer the benefit of higher aerodynamic performance by sustaining an attached shock wave at the leading edge. Inverse design methods are typically used to generate waverider shapes by combining an a priori desired flow field with streamline-tracing starting from the rear of the vehicle. A difficulty of these inverse design methods is to perform valid parameter space explorations or design optimisation tasks, for which direct optimisation frameworks are better suited. This work builds on the direct optimisation approach introduced by Son et al. (Aerospace, Vol 9, Issue 7, 2022, 348) in which four parameters are used to define waverider shapes. An in-depth exploration of the design space is presented based on similar methods consisting of inviscid CFD-derived surrogate modelling followed by genetic algorithm-based optimisation of aerodynamic performance and internal volume. Focus is placed on open-source software release and the wide-speed problem approached through a cost function incorporating information from simulations at multiple Mach numbers.Aerospace Science and Technolog
Scalable decarbonisation for the invisible majority - a data-driven framework to support a just transition for UK manufacturing SMEs
No full textDecarbonisation of the UK manufacturing sector is essential to achieving net zero, yet current industrial strategies focused on clusters overlook dispersed sites, which account for nearly half of manufacturing emissions. These sites are largely composed of small and medium-sized enterprises (SMEs), constrained by limited capacity, capability, and capital. Despite accounting for over 99% of UK manufacturing businesses, SMEs remain underrepresented in decarbonisation policy and emissions frameworks. This study addresses that gap by developing a hybrid modelling approach, combining two composite indicators, adapting the Bloomberg industry-implied carbon intensity model and an employment-based estimate from The Data City. By integrating these proxies in a 50:50 weighting and stress-testing through Monte Carlo simulations across the 19,130 manufacturing SMEs in the East of England, this research generates the first probabilistic baseline of SME emissions at regional, sectoral, and organisational scales. Results show that medium-sized firms contribute nearly 60% of regional SME emissions, while a small number of subsectors account for over 80%, underscoring concentration and volatility. High relative standard deviations highlight structural uncertainty yet also offer actionable insights by pinpointing where interventions can be targeted. By demonstrating that robust regional baselines can be built from imperfect secondary data, the research challenges the notion that SMEs are too fragmented to integrate systematically into decarbonisation policy. The thesis concludes that a just transition requires embedding SMEs into industrial frameworks through tiered fiscal instruments, interoperable digital tools, and place-sensitive strategies, reframing them as active agents of industrial transformation rather than peripheral actors.MSc in Environmental Management for Busines
Are two bodies in a trench a mass grave? an attempt to bridge the gap between single and mass graves
No full textWarning: This article contains images of mass Graves from genocides, which some may find disturbing.The definitions for mass graves proposed in the past concentrated on the minimum number of casualties and whether they were in a connected body matrix. This meant that many graves practitioners encounter could not be classified properly. They were neither a single grave nor a mass grave. This article proposes four key measures to address the grave classification issue. Firstly, it introduces three simple criteria to assist in classification. Secondly, it suggests three new grave types (cluster, trench, and serial grave) to name the most common graves. Thirdly, a final grave type, the multiple grave, is added to describe any grave that does not fit into any of the other categories. Finally, this article suggests that the threshold between multiple and many casualties, i.e. how many casualties constitutes a mass grave, should be set for each individual conflict or context rather than aiming for a universal figure. These four measures are designed to be simple, intuitive and flexible enough to allow practitioners to use grave labels that make sense in their particular context for forensic and legal professionals as well as the general public.Forensic Archaeology, Anthropology and Ecolog
The impact of heat transfer effects on civil aircraft engine transient performance
No full textPilidis, Pericles - Associate SupervisorDuring gas turbine transient manoeuvre, heat transfer occurs between the fluid
and metal. This results in various heat transfer effects, including heat soakage,
tip clearance, and change in component performance map. These will cause heat
loss and change in component flow characteristic and efficiency, which further
affect gas turbine transient performance. In this work, a comprehensive heat
transfer model including heat soakage, tip clearance and compressor map
modification has been developed. The proposed heat soakage model improves
the current state-of-the-art model by establishing a comprehensive thermal
network with the consideration of the combustor temperature distribution and
cooling technologies including film cooling, internal cooling, and thermal barrier
coatings. Additionally, the proposed novel compressor map modification model
can derive numerical correlations for compressor maps based on movement of
compressor speed line and map scaling, enabling the modification of adiabatic
maps to non-adiabatic maps during transient simulations. It improves the current
compressor map modification models by ensuring both flexibility and accuracy.
The developed heat transfer model has been integrated into Cranfield gas turbine
simulation platform Turbomatch, enhancing the realism of transient simulations.
The accuracy of the proposed model has been validated against data from public
sources, simulation platforms, and experimental results. A sensitivity analysis has
also been conducted to assess the impact of various assumptions on heat flow
rate estimation. The impact of heat transfer to overall engine’s performance has
been demonstrated by simulating transient operation of a turbojet and two
turbofan engines to demonstrate the effects of heat transfer on gas turbine
transient performance. Comparing with the conventional heat soakage method,
the application of the improved models can capture a delay on engine’s response
beyond the one simulated by the existing methods. This is a result of considering
the combustor temperature distribution and cooling technologies, not included in
the conventional heat soakage models. For the impact of heat transfer effect on
compressor characteristic and performance, a 4% reduction in compressor surge
margin is observed during a hot reslam transient manoeuvre, as a result of
movement in compressor speed line due to heat transfer effect.PhD in Aerospac
Advancing energy flexibility protocols for multi-energy system integration
No full textThis study investigates the incorporation of a standardised flexibility protocol within a physics-based models to enable controllable demand-side flexibility in residential energy systems. A heating subsystem is developed using MATLAB/Simulink and Simscape, serving as a testbed for protocol-driven control within a Multi-Energy System (MES). A conventional thermostat controller is first established, followed by the implementation of an OpenADR event engine in Stateflow. Simulations conducted under consistent boundary conditions reveal that protocol-enabled control enhances system performance in several respects. It maintains a more stable and pronounced indoor–outdoor temperature differential, thereby improving thermal comfort. It also reduces fuel consumption by curtailing or shifting heat output during demand-response events, while remaining within acceptable comfort limits. Additionally, it improves operational stability by dampening high-frequency fluctuations in mdot_fuel. The resulting co-simulation pipeline offers a modular and reproducible framework for analysing the propagation of grid-level signals to device-level actions. The research contributes a simulation-ready architecture that couples standardised demand-response signalling with a physics-based MES model, alongside quantitative evidence that protocol-compliant actuation can deliver comfort-preserving flexibility in residential heating. The framework is readily extensible to other energy assets, such as cooling systems, electric vehicle charging, and combined heat and power (CHP), and is adaptable to additional protocols, thereby supporting future cross-vector investigations into digitally enabled energy flexibility.Energie
Lung epithelial and alveolar macrophage-like cell interactions significantly modify innate responses to bacterial endotoxin with the involvement of direct cellular contacts, TNF-α, ICAM1 and MCP-1
No full textIntroduction: Lung alveolar macrophages (AMs) and epithelial cells form the first line of defense against inhaled pathogens. Their interactions strongly influence innate immune responses in the lung, yet the mechanisms underlying this cross-talk remain incompletely understood.
Methods: In this study, we established a co-culture system using a primary model of AMs (MPI alveolar macrophage-like cells) and MLE-12 alveolar epithelial cells to investigate innate responses and cellular interactions during bacterial lipopolysaccharide (LPS)-induced TLR4 activation.
Results: Cytokine and chemokine profiling revealed that co-cultures exhibited significantly enhanced proinflammatory responses to both LPS and TLR2 ligands—including IL-6, TNF-a, and MCP-1 secretion—compared with mono-cultures. Strikingly, we identified MLE-12 epithelial cells as a source of lipopolysaccharide-binding protein (LBP), which is essential for LPS recognition in AMs and MPI alveolar macrophage-like cells. LBP secretion by epithelial cells explained cytokine responses to LPS under serum-free conditions; however, additional mechanisms—apparent in the presence of serum/LBP—also contributed to the amplified co-culture responses. These mechanisms included direct cell–cell contacts, as conditioned media from unstimulated cells failed to reproduce similar effects in mono-cultures. Moreover, co-cultures of naïve MPI cells and inflamed epithelial cells (MLE-12 cells pretreated with media from activated MPI macrophages) were found to release a nonnegligible amount of chemokines, even in the absence of LPS. This demonstrated an inflammatory amplification loop mediated by both contact dependent and soluble factors. Phospho-flow cytometry further revealed coculture- specific signaling, with enhanced MAPK pathway activation in macrophages and NF-kB activation in epithelial cells. Finally, LPS-activated MPI alveolar macrophage-like cells induced TNF-a–dependent ICAM-1 expression and apoptosis in MLE-12 cells. Increased ICAM-1 expression, in turn, promoted MCP-1 production in epithelial cells in an ICAM-1–dependent and cell contact mediated manner.
Discussion: Together, these findings identify cellular contacts and a TNF-a–ICAM-1–MCP-1 axis—supported by epithelial-derived LBP—as key drivers of innate immune synergy between lung alveolar macrophages and epithelial cells. Our results establish the MPI–MLE-12 co-culture as a tractable model for dissecting pulmonary innate immune mechanisms.This research was supported by the National Research Foundation of Korea (NRF) funded by the Korean government (MSIT), through institutional grants NRF-2017M3A9G6068246 and RS-2024-00398073. This work was also funded by grants from the United Kingdom NERC BioAirNet (NE/V002171/1)Frontiers in Immunolog
Managerial overconfidence and information opacity: evidence from China
No full textThis study examines how managerial overconfidence affects information opacity in China… We find that overconfident managers significantly increase information opacity. This effect is amplified in firms embedded in strong Confucian cultural environment, where hierarchy and harmony norms suppress the effectiveness of board oversight. However, external governance mechanisms are found effective in constraining overconfidence-induced opacity. Our findings suggest that the overconfidence-opacity relationship is contextually dependent and varies with cultural environment and governance quality. The results carry important implications for regulators and investors in the Chinese emerging market.Review of Quantitative Finance and Accountin