Power and Infrastructure research projects

Investigation of the Impact of Mixing Regimes on Sedimentation in Anaerobic Digesters through CFD Modelling for Process Optimisation of Biogas Production

• PhD Student: José Carlos Nogueira Filho
• Supervisors: Prof John Bridgeman & Prof Mark Sterling
• Duration: 2015-2019

Mesophilic anaerobic digestion is the most widespread technology for the treatment of sewage sludge, a by-product of wastewater treatment. Sludge is mixed with anaerobic bacteria at temperatures between 22 and 41 degrees Celsius, and biodegradable material is broken down into more stable compounds, producing a methane-rich biogas during the process. Biogas, in turn, is increasingly harnessed as a renewable energy by means of combined heat and power technology. In order to understand how to enhance digester mixing, it is important to determine to what extent biogas output is influenced by flow patterns in a digester; flow patterns which are determined by physical parameters of the digesters, inflow mode, sludge rheology and, crucially, mixing regimes. However, research is still lacking in this area. Traditional approaches to digester design are firmly rooted in empiricism and rule of thumb rather than science, and design standards focus only on treated sludge quality, not quality and gas yield/energy consumption.

This project aims to enhance biogas output of anaerobic digesters through an analysis of the sludge flow patterns during mixing. Two-phase (liquid-solid) and three-phase (liquid-solid-gas) computational fluid dynamics (CFD) models will be built to investigate the interactions between mixing, sedimentation and biogas production. Lab-scale experiments will be undertaken to ensure model validation.

Measuring City Performance: Development of a City Analysis Methodology (CAM) to Assess the Liveability of UK Cities

• PhD Student: Joanne Leach
• Supervisors: Prof Chris Rogers & Dr Dexter Hunt
• Duration: 2012-2018

Recent years have seen increasing public, private and policy interest in the performance of cities, especially with regard to sustainability, climate change, resilience and, more recently, liveability. This has mirrored the increased attention being paid to cities more generally as engines of change and sites of economic and population growth. In order for cities to move towards increased liveability, it is important first to understand how cities function and how well they perform. This provides a baseline against which to identify and prioritise aspects that would benefit from change and assess the impact of any proposed interventions. Gaps in performance can then be identified, barriers to achieving a liveable future elucidated, and robust interventions designed and assessed. City performance refers to how well or poorly a city is functioning when set against defined criteria (e.g., sustainability, resilience, liveability). The assessment of a city’s performance is inherently influenced by how performance criteria are conceptualised and how they are measured. In order for the performance data to be useful, a determination of what constitutes ‘good’ performance must be made. Who does this, and how, materially influences the conclusions drawn. As such, the transparency of this information is crucial for policy making. Current city performance assessments are many and vary in criteria, measurement methodology, robustness, transparency and applicability to specific urban contexts, with no single method dominating. This presents a challenge to policy makers and others wishing to use these methods to inform policy.

This PhD programme is developing a City Analysis Methodology (CAM) specifically designed to aid UK policy makers by taking account of a uniquely broad set of perspectives (liveability). It proposes a new, relational conceptual framework for measuring the performance of cities as well as delivering unique insights into the performance of Birmingham, Lancaster and Southampton. The research forms part of Liveable Cities, a 5-year research programme exploring pathways to low-carbon, resource-secure cities in which societal wellbeing is prioritised, while changes in population, demography, climate, security of energy / other resources, and a plethora of historical legacies, provide the context (see www.liveablecities.org.uk).

• PhD Student: Khalid Dahmash
• Supervisors: Prof Chris Rogers & Prof David Chapman
• Duration: 2016-2019

There is current a global boom in construction allied to the growth in the world’s population. With more than 50% of the global population living in the cities, and the proportion expected to increase to 70% by 2050, the need for infrastructure is escalating. Going underground is considered to be a future ‘sustainable solution’ in urban areas. However, going underground is potentially dangerous. A lack of essential information (e.g. geotechnical and geological surveying data) allied to poor management of information on the underground is one of the basic reasons underlying construction risk, uncertain and often large costs, and not infrequently accidents. Building Information Modelling (BIM) systems provide a suggested solution to manage all subsurface information and help make explicit and visualise different types of risk.

The aim of this research project is to develop a Subsurface Building Information Modelling system to manage all relevant information during planning, designing, building and operating underground projects associated with buried infrastructure. Importantly, tracking subsurface information during building and updating the Subsurface BIM will enable visualisation of the data by each member of the project team to avoid conflicts.

A numerical and experimental investigation on installation and bearing capacity of suction caisson foundations for offshore wind turbine

• PhD Student: Koohyar Faizi
• Supervisors: Dr Asaad Faramarzi, Dr Samir Dirar, Prof David Chapman

Suction caisson foundation is an upturned bucket of cylindrical shape made from steel, open at the end and closed at the top. The simple installation and easy removal process, plus the low costs of materials and installation procedure are among some of the advantages of suction caisson compared with conventional solutions such as mono-piles. In general, the cost of installation for the foundation of offshore wind turbines can be up to 40% of the total installation cost; suction caissons can significantly reduce this figure since their installation only requires a pump! This has made suction caissons a promising attractive option for use in offshore wind turbine. Despite many advantageous, these types of foundations have not yet been adopted for foundations of offshore wind turbines.

This multidisciplinary research project will look at geotechnical, structural and fluid aspects of the problem to explore installation, bearing capacity and long-term functioning of suction caissons under various, yet realistic, loading and environmental conditions. The problem will be investigated by means of numerical, experimental and analytical approaches to analyse and predict both short-term and long-term behaviour of caissons under the effect of complex loading, and soil-structure interaction during their service life. The result of this project is expected to determine the suitability of using suction caissons as a foundation for wind turbines.

• PhD student: Rachel Fisher
• Supervisors: Dr Andrew Quinn and Dr David Jaroszweski
• Duration: 2015-2020

Great Britain’s railways are considered to be a resilient transport network compared to other modes, however over the eight years preceding the winter of 2013/14, weather and seasonal events on average could be attributed as the cause of 12% of delays on the railways. Railways are subject to a multitude of weather hazards and continuing operation is crucial to the socioeconomic performance of the country thus the aim of this project is to develop a methodological approach to assess the vulnerability of physical infrastructure assets to the effects of weather, both now and in the future by incorporating deterministic and probabilistic methods.

Emissions Charges, Environmental Attitudes and Uptake of Ultra-Low Emission Vehicles: Insights from Stated Preference Data Analysis

• PhD student: Michael Mammo
• Supervisors: Prof Miles Tight & Dr Andrew Quinn
• Duration: 2015-2019

The UK's 'Dieselisation' of vehicle fleet in recent years has been an enormous challenge. By 2014, there were 10.7 million diesel cars, representing 36% of the total road fleet, in contrast to only 1.6 million in 1994 (DfT, 2015). Failure to control the growth of diesel fleet on the road has resulted in UK failing to meet the values for NOx set out in the EU Ambient Air Quality Directive in many cities.

To counter this challenge, the City of London is planning to introduce a stringent emissions charging scheme (ULEZ) in the city centre by 2019. Birmingham has also been mandated by DEFRA to introduce a Clean Air Zone (CAZ) Scheme by 2020.

The main objective of the present research is to gain an understanding of how car owners in Birmingham and London would make vehicle replacement and journey-specific decisions when faced with emissions charges. A stated preference survey data will be used to study the trade-offs that car owners make between a range of vehicle attributes, emission charges and incentives when making car replacement decisions, and how these choices are influenced by their socio-economic backgrounds and environmental attitudes.

• PhD student: Isimenmen Obazele
• Supervisors: Prof Chris Baker & Dr Andrew Quinn
• Duration: 2014-2018

Climate change has resulted in the increase of extreme weather conditions. Inclement weather conditions induce negative effects on transportation capacity, speed, safety and infrastructure resilience. Both mitigation and adaptation strategies are currently being adopted to curb these impacts. Such strategies include improving drainage systems and attempting to reduce carbon concentrate in the atmosphere through various programs such as afforestation and promoting the use of renewable energy.

This project aims to predict the resilience of sections of the UK’s motorway network to future weather conditions (precipitation and temperature).

Infrastructure Management: Devising a Business Model for Transport Interdependencies Management

• PhD Student: Nikolaos Kalyviotis
• Supervisors: Prof Chris Rogers & Prof Miles Tight
• Duration: 2015-2018

There is an ongoing debate about the value of the benefits of infrastructure systems (specifically those of energy, water, transport, waste, and communications) and how to prioritize infrastructure investments to encompass considerations of social, economic and environmental wellbeing. The use of the term ‘infrastructure system’ is related to interdependencies.

The infrastructure systems that operate in countries and cities are interrelated in different ways, but all have a strong relationship to ‘transport’ – there is a cost and a utility associated with movement. Infrastructure systems are ultimately created to serve individuals, who place a value on them. In order to explore all forms of investment and value realisation – what is commonly termed a business model – the relationship between an individual and the transport systems needs to be established.

The hypothesis being tested in this research is that it is possible to identify both the full range of value created and investments required, and hence to establish a robust business model, for transport systems.

An Underground Information System in support of Sustainable, Resilient and Liveable Cities

• PhD Student: Stylianos Providakis
• Supervisors: Prof Chris Rogers & Prof David Chapman
• Duration: 2016-2019

Nowadays, most of the human population lives in cities and most of our everyday lives lie within their environments and interconnections. Moreover, these cities are expanding and as a result their design and planning is important for their future. Sustainability and resilience, two major contributors for urban liveability, owe much to the urban geological characteristics and processes of the cities’ underground. That is, they are dependent both on the resources of the subsurface and the geo-hazards that they present – important factors for the future of cities that can provide sustainability and safety, respectively, avoiding costs in the long term.

This research project utilizes the geological data derived from various urban ground investigations in order to develop 3D Geological Models. It also combines Building Information Modelling technology, extended in this case to the ground beneath cities, in order to explore the relative physical or manmade effects that occur in the underground. These effects change the geotechnical and other geo-environmentally related properties with time after construction of city developments occurs. The aim is to provide a multi-objective tool to determine the geo-environmental impact on future land use planning that is of relevance in selecting suitable sites for development and bringing about sustainable urban design.

Can a Hybrid Critical Realist Model of Emergent Citizen(Ship) Enhance Future City Thinking? Modelling and Characterising Citizens in Urban Areas to Inform Planning for Resilience, Infrastructure and Quality Of Life

• PhD student: Jonathan Ward
• Supervisors: Prof Chris Rogers, Prof Miles Tight, Prof Jon Sadler & Dr Dexter Hunt
• Duration: 2015-2018

In order to plan for future cities we should start by questioning human experience and systemic relations with the urban environment, as people are the heart and purpose of cities. We must ask what is a citizen, and indeed what makes a human a citizen in terms of their relations and interactions? Current approaches to describing and modelling social beings are often unable to properly reconcile sociality and relations with so-called 'hard systems'.

This thesis will seek to provide explanations of emergent behaviour from an individual and societal perspective. This requires that we treat society and social actions (or beings) as real and knowable. Critical Realism’s inherent ability to consider wholly the natural and social sciences, differentiate in the generality of findings, and to look for rules to describe behaviour, offers an opportunity to treat this subject in a new manner. Using Critical Realism as a lens leads to an explanatory study of underlying mechanisms and structures that shape how we move from beings to actors and citizens through our use of objects, relationships and interactions in particular places.

Focussing enquiry upon the citizen could assist our understanding of how infrastructure and new technologies will mediate their relations with the physical, social and natural world around them. If we can understand that, we can inform the thinking and design behind the Future and Smart Cities discourse. We can then begin to understand the possible directions of travel of society and citizen behaviour given certain conditions and emerging technologies. The thesis will seek to (re)define the relationship between citizens and cities in a more emergent manner, and the definition of what it means to be human in a networked age.

• PhD student: Carlo Liui
• Supervisors: Prof Miles Tight & Dr Michael Burrow
• Duration: 2014-2018

This research is investigating how urban transport systems can be made to better meet the needs of an older population. Gerontological research is putting increasing focus on the role that mobility plays in later life. Analysis of studies investigating the relationship between ageing and mobility reveals that these are generally characterised by relying only on realised mobility. However, very little has been investigated so far in terms of unrealised mobility, and often with different approaches and results.

Through an intensive review of approaches existing in the literature, this study develops a theoretical framework to investigate which mobility needs remain unfulfilled. It first assesses the concept of mobility needs in later life. This concept is then used to evaluate the best method to investigate factors and barriers leading to unmet travel needs. Five main domains were finally identified necessary to be considered: experience and attitude towards mobility; built environment, well-being and quality of life, health conditions and socio-demographic background characteristics. These will be further explored through interviews with older people in Birmingham, in part drawn from the Birmingham Elders project.

• PhD Student: Sameeh Alharthy
• Supervisors: Prof Miles Tight & Dr Michael Burrow
• Duration: 2014-2018

The aim of this study is to improve the level of understanding on the impacts of features of the transportation service and urban form on walkability in the vicinity of public transport, specifically suburban train stations. The research is developing a model of which are the critical aspects which affect walkability of the urban environment and how these factors might be enhanced in the close vicinity of public transport facilities.

The work is considering both macro and micro aspects of the built environment. To date it has involved a GIS based analysis of a number of suburban rail stations and their vicinity in Birmingham using publicly available sources of information such as use of the stations, service level of trains, density and characteristics of population and quality and type of infrastructure. The next stages will involve a detailed exploration of the local environments at a smaller sample of stations to attempt to understand more about how the micro characteristics of the lo0cal environments could be improved.

Understanding the importance of the link between good public transport provision and walking in urban areas

• PhD student: Dennis van Soest
• Supervisors: Prof Miles Tight & Prof Chris Rogers
• Duration: 2016-2020

There is evidence that a substantial proportion of walk trips in urban areas take place at each end of other main mode trips (for example walking to the bus stop) and these are often ‘hidden’ if the data collection method does not distinguish each trip stage. Whilst there are often walk stages at the start and end of car trips and sometimes cycle trips, the largest number (and greatest distance) is associated with public transport. Hence, public transport is a generator of walk stages and good well-used public transport systems can be shown to contribute to walking levels and encourage more active and healthy transport.

This research project would explore this relationship in more detail across a number of case study urban areas and also seek to explore how variable the information on walking is across different places. It would seek to understand if there are constraints or limits to the amount of walking associated with public transport trips and therefore if there are implications for ideal city form/design and public transport coverage/type to promote healthier transport options.

The effect of Atmospheric Turbulence in the built environment on the performance of Wind Turbines

• PhD Student: Giulio Vita
• Supervisors: Dr Hassan Hemida & Prof Lambis Baniotopoulos
• Duration: 2015-2018

In the near future, Urban wind energy could see a massive growth, due to its undeniable advantages. However, the performance of wind turbines under highly turbulent inflow, which can be found within the Urban Boundary Layer, is far from being fully understood. This specially applies to the signature turbulence on the wake of other obstacles which interact. In particular, the role of the length scale of turbulence is challenging. This research investigates, on one hand, the effect of the inflow turbulence on stalled wind turbine aerofoils, which are complex bluff bodies. On the other, the turbulence within the urban environment is tackled, with special reference to the positioning of wind turbines for the optimisation of the harvesting of energy, regarding high-rise building and their roof area. Both experimental (wind tunnel) and numerical (computational fluid dynamics) will be carried on, focusing on the application of Large Eddy Simulation on a series of simplified and detailed models. Turbulent inlet techniques will be also assessed in their practicability in enhancing the usage of numerical methods.

This project will start a constructive discussion on the negligibility of turbulence as a parameter for the calculation of the aerodynamic coefficient, using wind energy and the urban environment as an current and challenging test-case. The research is founded by the European Commission within the Marie Curie ITN project Aeolus4Future, (cfr. www.aeolus4future.eu).

Novel Communication Design For Buried Water Pipe Monitoring Through The Use Of Acoustic Signal Propagation Along The Pipe

• PhD Student: Omotayo Farai
• Supervisors: Dr Nicole Metje, Prof David Chapman, Dr Carl Anthony
• Duration: 2015-2018

The UK has a vast network of utility and local authority infrastructure buried beneath highways and footways in the UK. The combined network of water, sewer, gas and electricity services extends to over 1.5 million km. Most of these buried assets are ‘dumb’ and have little sensing capabilities. However, increasingly discrete sensors are developed to monitor the condition of the asset or its content. Most of these rely on electromagnetic signal transmission which is hampered by the soil and the water within it to such an extent that transmission can be in the worst case only a few cm. Alternative signal transmission using acoustic signals are investigated as part of this project with the aim to achieve several 10s of metres.

• PhD Student: Omotayo Farai
• Supervisors: Dr Nicole Metje, Prof David Chapman, Dr Carl Anthony
• Duration: 2015-2018

The UK has a vast network of utility and local authority infrastructure buried beneath highways and footways in the UK. The combined network of water, sewer, gas and electricity services extends to over 1.5 million km. Most of these buried assets are ‘dumb’ and have little sensing capabilities. However, increasingly discrete sensors are developed to monitor the condition of the asset or its content. Most of these rely on electromagnetic signal transmission which is hampered by the soil and the water within it to such an extent that transmission can be in the worst case only a few cm. Alternative signal transmission using acoustic signals are investigated as part of this project with the aim to achieve several 10s of metres.

• PhD Student: Guanyu Wang
• Supervisors: Dr Michael Burrow & Dr G Ghataora
• Duration: 2015-2018

The periodic assessment of road condition is a vital aspect of road asset management in that it aids the selection of appropriate and timely road maintenance. Road condition is a major contributor to road use costs. Poor road condition affects fuel consumption, vehicle maintenance, journey time and accident costs. The comprehensive assessment of road condition periodically requires a number of parameters to be collected including ride quality (or road roughness), surface distress (cracking), surface friction (skid resistance) and structural performance (deflection). These parameters however are expensive and time consuming to collect at sufficient accuracy to support road asset management of large road networks. A number of commercially available computer applications that claim to be able to assess various measures of road condition when used with smart phones fitted to moving vehicle. These include the identification of discrete road defects (such as potholes) and the roughness of entire road sections. However, the accuracy, repeatability and reproducibility of these tools are unknown.

The aim of this research project is to investigate, whether and how, road condition data collected using smart phone technology may be incorporated within a comprehensive decision support system that facilitates the asset management of road networks and provides road users with information to inform journey costs.

Investigating the relationships between geotechnical properties of saturated fine-grained soils and ER/TDR measurements

• PhD Student: Anna Faroqy
• Supervisors: Prof David Chapman, Dr Alexander Royal, Dr Giulio Curioni
• Duration: 2014-2017

Electrical Resistivity (ER) and Time Domain Reflectometry (TDR) are geophysical tools that can be used for spatial and temporal ground data collection. Both techniques have been independently tested in geotechnical applications and recognised mainly for their clear response to ground water changes. Given that water is a major factor affecting the geotechnical properties of soils, there has been ongoing research into translating geoelectrical responses into geotechnical proprieties. Interpreting geophysical data, however, is often very problematic due to the variable nature and conditions of the soil. Nonetheless, calibrating ER and TDR to a specific soil has been found to provide more informative results, making these techniques a promising monitoring method that could advance the understanding of the behaviour of soils in-situ.

Although complementing ER, which provides good spatial coverage, with point measurements from TDR can enhance ground data interpretation, research on simultaneous application of both methods is very limited. Therefore, the aim of this research is to combine ER and TDR tests to enhance the translation of soil electromagnetic responses into geotechnical property changes. This will be achieved through controlled laboratory experiments on selected fine-grained soils during 1D consolidation, incorporating both ER and TDR measurements.

• PhD Student: Mohammadreza Mohammadi
• Supervisors: Prof Chris Baker & Prof Mark Sterling
• Duration: 2016-2020

Lodging, the permanent displacement of stems from the vertical and the associated issue of yield and quality reductions have received much attention over the last ten years. Much of this focus has been directed to crops such as wheat and barley. Ireland grows very high quality oats with the potential to significantly increase exports for human consumption and as equine feed however they are prone to lodging, but relatively little work has been undertaken in order to improve its lodging resistance. This lack of work is partly due to the complex nature of the plant and the multidisciplinary nature of the work; knowledge of crop physiology and wind engineering principles are required in order to scientifically model and hence understand the lodging process, and reduce lodging risk. Important gaps in knowledge are understanding how crops with inter-locking canopies interact with wind and lodge, how the strength of stems vary up the length of the stem and the root traits that determine anchorage strength.

The proposed research combines the expertise of agronomists, crop physiologists and wind engineers in order to investigate lodging in oats. The research explores the applicability in field conditions of a theoretical model which has been developed by the team to assess lodging in oats. Through the use of a large number of field-scale trials, the model will be further developed and calibrated as appropriate. The model will then be used to investigate which plant parameters affect lodging the most and to specify the plant character values required for lodging proofness. The model will be used to quantify the effect of changes in agronomic practices on lodging risk, which will form the basis of an improved lodging risk and management scheme. It will also be used to guide the efforts of plant breeders by identification of the key traits for genetic improvement. The effect of possible climate change on the risk of lodging in the crop will also be investigated through the model.

• PhD Student: Frederick Bourriez
• Supervisors: Profs Chris Baker, John Bridgeman and Mark Sterling
• Duration: 2015-2018

The highest wind speeds on Earth often arise as a result of tornadoes. The May 2013 US tornadoes demonstrated yet again the power of these events and the complete devastation and consequent loss of life that can occur within a very short timescale. Further devastation and more deaths resulted a couple of weeks later when tornadoes occurred again in Oklahoma. North America is not alone in experiencing devastating tornado outbreaks with frequent tornado related damage reported on an annual basis across South America, Australia, Asia and Europe. Society’s risk to extreme storms such as tornadoes is increasing due to expanding and wealthier populations, with more valuable assets at risk. Debris has the propensity to get embedded within tornadoes and to reach significant speeds. The impact of such debris on engineering and non-engineering structures has the potential to cause more damage than the wind itself and to create further debris which in itself may be transported by the local wind field.

This research involves both physical and numerical simulations in order to track the path of debris items embedded within a transient wind field of a tornado. The simulations will be compared with existing theoretical models for debris flight and used to establish a set of guidelines for engineers.

A validation of our currently used physical tornado-like vortex generators regarding their geometric influence on the flow characteristics

• PhD Student: Stefanie Gillmeier
• Supervisors: Prof Mark Sterling & Dr Hassan Hemida
• Duration: 2015-2018

Tornadoes can generate wind speeds of significant magnitude which can result in devastating damage. To prevent this, a better understanding of wind and pressure fields within and near tornadoes is required. Obtaining real life data for such winds is fraught with challenges. For this reason, physical and numerical simulations are used to safely generate tornadoes under controlled conditions. Aim of this research is to improve the representation of full-scale tornadic events in physical tornado simulators.

Main research focus is to outline and discuss challenges when modelling tornado-like vortices experimentally focusing on the influence of the generator’s geometry on the flow and pressure field. Several different simulations will be undertaken, during which the dimensions of the simulator will be varied whilst the swirl and aspect ratio is kept constant. This fundamental work will, for the first time, enable a thorough comparison between simulations undertaken in different simulators to be appropriately interpreted.

• PhD Student: Amelia Rouse
• Supervisors: Dr Nicole Metje, Prof David Chapman, Prof Ian Jefferson
• Duration: 2015-2018

The research focuses on improving existing root anchorage failure models. The project aims to develop an improved model for the root-soil interaction by considering different root structures as well as soil types, compaction and water content amongst others. The objectives are to develop idealised root structures for the laboratory, which can then be instrumented with strain gauges and artificially ‘lodged’. This will be repeated for a number of different soil types and conditions. Field trials in Ireland are used to inform, and validate, the findings from the laboratory.

The result will be an improved model for root anchorage failure, which can then be used to produce plants with improved root anchorage characteristics. The data will be analysed using techniques such as spectral analysis, wavelet analysis and structural analysis.

The Water-Energy Nexus - Quantifying the impact of future water-energy nexus constraints on the UK thermal generation power station fleet, both in terms of cost and technology

• PhD student: Daniel Murrant
• Supervisors: Dr Andrew Quinn & Prof Lee Chapman
• Duration: 2013-2016

The combined effects of increasing water and energy demand due to a growing population and climate change pose a growing threat to many national infrastructure strategies. Within the UK there is concern that a future lack of available water will compromise the UK’s current energy policy to meet an increasing demand for a secure and affordable supply of electricity by more thermal generation. This project investigates this by modelling the water demand of the UK’s thermal electricity generation in 2030 and 2050, relative to 2010, for the strategically important Carbon Plan, and the Energy Technologies Institutes’ ESME generation pathways using water abstraction and consumption figures specific to UK power stations.

• PhD student: Simon Hodgkinson
• Supervisors: Dr Andrew Quinn, Prof Lee Chapman, Dr David Jaroszweski
• Duration: 2015-2019

This research concerns the role of extreme weather as an instigator of cascading infrastructure failure. Extreme weather events can cause significant damage to the built environment, with infrastructure assets being of particular concern. Networked infrastructure, such as transport and energy, are interdependent in that they place demands upon each other for a resource. When one network is disrupted, the flow of a resource is also disrupted and failure can cascade on to dependent networks. There is a strong dependence of the railway network on the electricity system for a supply of electrical power, both for traction and safety-critical elements.

This project aims to assess and quantify the problem of cascading failure from electricity to railway infrastructure during extreme weather events. It takes a practical data-driven approach, combining both infrastructure fault and meteorological data to identify the relationships between physical failure and weather events, along with an assessment of spatio-temporal fault distributions to identify particularly vulnerable assets. Subsequent projections of cascading failure under future climate scenarios will ultimately result in a series of recommendations or suggestions for the rail industry to ensure network resilience.

Performance of Multi-junction solar cells under high concentration ratios and the harsh environment in Saudi Arabia

PhD Student: Mr. Abdulrahman Aldossary

Supervisors: Dr. Raya AL-Dadah & Dr. Saad Mahmoud

Duration: 2012-2016

Solar Photovoltaic (PV) power has been one of the fastest growing renewable energy technologies and it is anticipated that this technology will play a major role in the future of global electricity generation. The main challenge of using PV is the high initial cost when compared to electricity generated from conventional sources. In order to increase the efficiency of solar power generation and make it more cost effective, different methods have been considered and several approaches have been introduced and investigated. One approach for cost reduction in solar power generation is using mirrors, reflectors or lenses to concentrate the incoming solar irradiation on the PV. Multi-junction (MJ) solar cells are recently favoured over single junction cells to be integrated in high concentrator PV (HCPV) systems as they are more efficient, have a better response to high concentration, and lower temperature coefficient. The new technology, III-V generation MJ solar cells, offer high efficiencies exceeding (43%) at high concentration compared to traditional solar cells made of a single layer of semiconductor material. However, high concentration will cause high and non-uniform PV cell surface temperature which reduces the efficiency and power output from the cell and ultimately degrades its life.

Therefore, effective cooling is necessary to dissipate the heat load on the solar cell surface and maintain the peak performance in all conditions. Moreover, thermal energy carried by the coolant can be utilized in different thermal application such as water desalination and air conditioning; this concept is called HCPV/Thermal. In this project optical, electrical and thermal modelling is undertaken to predict the performance of the HCPV/T under different solar irradiation and ambient conditions especially in harsh environment like Saudi Arabia where ambient temperature can reach up to 50oC in summertime.

• PhD Student: Mr. Wisam Al-Shohani
• Supervisors: Dr. Raya AL-Dadah & Dr. Saad Mahmoud
• Duration: 2014-2018

Solar energy is abundant in Middle Eastern countries like Iraq and harnessing such renewable energy source will contribute to reducing carbon emissions both locally and worldwide. The use of silicon based Solar photovoltaic panels to generate electricity has increased significantly, however, their efficiency is low as they can only utilize part of the solar spectrum while the remaining part of the spectrum is converted to heat. Water can absorb the Ultraviolet (UV) and part of Infrared (IR), which are un-active spectra ranges for PV, and transmittance the Visible (VIS) and some of IR to the PV surface, which are active wavelength parts for PV.

This project investigates using water as an optical filter for Photovoltaic/Thermal (PVT) and Concentrating Photovoltaic/Thermal (CPVT) modules to reduce the heat accumulation in the cells and improve the overall efficiency.

• PhD student: Mrs Ghada Sadiq
• Supervisors: Dr. R. K. AL-Dadah & Dr. Saad Mahmoud
• Duration: 2013-2017

Hybrid engines for automotive applications offer the advantage of lower fuel consumption and CO2 emissions. The rotary Wankel expanders outperform other types of expanders due to their compactness, low vibration, noise and cost. This project aims to develop a Wankel multistage expander for compressed air hybrid engine using computational fluid dynamics CFD modelling and experimental testing to optimize the performance of the developed expander.

• PhD student: Miss Parya Karim Nejad Aliabadi
• Supervisors: Dr. Raya AL-Dadah & Dr. Saad Mahmoud
• Duration: 2012-2017

Currently, cryosurgical probes for cancerous tissues ablation use cryogenic fluids like liquid Nitrogen systems which are bulky and require many components to operate. Several drawbacks associated with these probes such as low controllability of probe temperature during freezing and the cooling rate, having less flexibility due to probe complex structure for having vacuum insulation and pressure proof. These probes were unable to perform rewarming after freezing process. Therefore separate warming element was utilized for rewarming the tissue after freezing cycles. In order to avoid the aforementioned complications and improve the practicability of cryosurgery for cancer tissue ablation, it would be advantageous to use thermoelectric device as an alternative to perform cooling and rewarming just by reversing its polarity. Thermoelectric devices are compact, lightweight, with no moving mechanical parts and are capable to control the temperature precisely.

Being environmentally friendly because of employing no refrigerant is another advantage of using thermoelectric cooler therefore leaking problems of refrigerant can be avoided. This study investigates the use of thermoelectric devices in cascaded form for generating the required freezing temperature for cancer tissue ablation.

• PhD student: Miss Eman Elsayed
• Supervisors: Dr. Raya AL-Dadah & Dr. Saad Mahmoud
• Duration: 2014-2018

Water scarcity is a natural and human-made problem that is endangering the mankind existence. Seven hundred million people around the world are suffering from water scarcity; another 500 million are approaching this situation. The situation is expected to worsen by 2025. With such a growth rate, new water resources and treatment techniques are urgently needed. One of the most promising alternative water resources is seawater as water represents more than 70% of the planet and 97% of this water body is saltwater. Desalination is generally defined as the process by which potable water is produced from the seawater or brackish water with high dissolved suspended solids content (>35000 ppm). Adsorption desalination is a desalination method that has many advantages such as being environmentally friendly, running on low grade heat sources and requiring low capital cost.

This study investigates the potential of a new class of adsorbents, metal-organic frameworks (MOFs), instead of the conventional adsorbents like silica gel and zeolite in the adsorption desalination application.

Development of solar powered small scale organic Rankine power generation system for domestic applications

• PhD student: Mr. Ayad Aljubori
• Supervisors: Dr. Raya AL-Dadah & Dr. Saad Mahmoud
• Duration: 2013-2017

Recently, the increase in fossil fuel consumption and associated adverse impact on the environment led to significant interest in renewable energy sources like solar and geothermal. Also, obtaining high turbine efficiency is necessary in order to achieve a high system performance in small size power output applications from low-temperature heat source and low mass flow rate. In this study, the design and 3D analysis and optimization of small-scale axial, radial inflow and outflow turbines are in investigated that can be utilized in Organic Rankine Cycle (ORC) for power generation which operate with low-temperature heat source (<100°C) and low mass flow rate.

Optimization of Small Scale Axial Turbine For Distributed Compressed Air Energy Storage System

• PhD student: Mr. Ali Bahr Ennil
• Supervisors: Dr. Raya AL-Dadah & Dr. Saad Mahmoud
• Duration: 2013-2017

Distributed compressed air energy storage (D-CAES) cycle is attractive – environmentally friendly energy storage option in small scale for stand-alone electricity generation using renewable energy sources. This research aims to improve the overall performance of D-CAES through turbine single and multi-operating point optimization. The dynamic modelling for the cycle is carried out using Matlab/Simulink for both charging and discharging phases in order to identify the turbine operating map. In D-CAES operation, there is a significant variation in air thermodynamic properties and as a result the turbine will be optimized for a range of operating condition by using CFD modelling and multi objective genetic algorithm optimization to achieve higher efficiency levels during discharging phase.

• PhD student: Mr. Ahmed Alammar
• Supervisors: Dr. Raya AL-Dadah & Dr. Saad Mahmoud
• Duration: 2013-2017

Heat pipes are effective devices for transporting thermal energy from one point to another using evaporation and condensation processes in a closed container. They have the advantages of low thermal resistance, compact and uses small amount of working fluid thus are used in wide range of applications such as electronics cooling, heat exchangers and solar collectors. Considerable interest has been paid to wickless Two-Phase Closed Thermosiphon (TPCT) heat pipes due to its simple construction and low cost. Computational Fluid Dynamic (CFD) modelling of a heat pipe is a powerful tool that can be used to investigate the complex physical phenomena of the evaporation and condensation phase change processes inside thermosiphon heat pipes.

This work aims to develop a CFD simulation model of two phase flow inside thermosiphon heat pipe to investigate heat pipes in terms of temperature distribution and thermal resistance using FLUENT (ANSYS 15). The work aims to also investigate the effect of critical parameters like fill ratio, surface texture and working fluid on heat pip performance.

• PhD student: Mr. Ahmed Daabo
• Supervisors: Dr. Raya AL-Dadah & Dr. Saad Mahmoud
• Duration: 2013-2017

Small scale solar thermal open Brayton cycle with Concentrated Solar Power CSP has the potential to offer higher power generation, higher efficiency and lower cost compared to other cycles. This project aims to develop an efficient small scale solar powered Brayton cycle through the optimization of the solar receiver configuration using advanced ray tracing simulation and thermal modelling. Also, the project aims to develop small scale turbines (axial/radial) that suit the various cycle operating conditions.