Fire and explosion modelling projects

Duration: 2021– 2022​.

Funding body: Transport Research and Innovation Grant (TRIG).

To establish hydrogen supply infrastructure at airport, onsite storage is likely to be based on liquid hydrogen. However, liquid hydrogen implies specific hazards and risks, which are very different from those of compressed gaseous hydrogen. The related specific issues, including leaks, fire, and explosion, need to be carefully addressed to ensure higher levels of safety provisions.

Warwick FIRE won one grant in the TRIG competition to evaluate safety zones and mitigation measures for hydrogen refuelling infrastructure at airports using the modified OpenFOAM code developed and validated in her previous EU and EPSRC funded hydrogen projects.

The CFD predictions will help to establish the horizontal and vertical extents of the flammable cloud following liquid hydrogen release during aircraft refuelling or catastrophic failure of storage tanks; and quantify the associated fire and explosion hazards associated. The results will be analysed to formulate recommendations for regulations, codes and standards, and mitigation measures.

Duration: 2021 – 2022​.

Funding body: SPL​.

SPL is developing a High Altitude Remotely Piloted (HARP) aircraft for telecommunications services. SPL’s HARP aircraft takes advantage of the high gravimetric energy density of liquid hydrogen to enable it to undertake long-endurance telecommunications operations carrying SPL’s unique, high-powered phased array antenna.​

Warwick FIRE supported SPL as a sub-contractor to win an award from The Transport Research and Innovation Grant (TRIG) competition. The in-house modified OpenFOAM will be used to simulate four specific scenarios including vent gas caused by passive heat leak into both liquid hydrogen tanks, full bore break of tank nozzle, inadvertent jettison on ground and failure of wing-mounted fuel line. The predictions will be used to establish the regions with hydrogen concentrations to be within the flammability limits. The results will inform SPL in its development of a conceptual analytical tool for screening analysis to establish the size and contents of airfield safety zones on the runway, taxiway and apron areas, needed for the operation of liquid hydrogen-powered aircraft.

Duration: 01/01/2018 - 31/12/2020.

Funding body: EU Clean Hydrogen Partnership​.

Project budget: €1.905.863.

PRESLHY is a pre-normative research for the safe use of cryogenic liquid hydrogen (LH2) funded by FCH 2 JU. The consortium consists of European key organisations from the International Association for Hydrogen Safety HySafe with the relevant background related to LH2 safety research and will be coordinated by Karlsruhe Institute of Technology KIT.

The work program duly refers to the outcomes of Research Priorities Workshops commonly organized by IA HySafe, EC JRC, and US DoE. Via HySafe and IEA HIA it will be aligned with other international activities also dedicated to safety issues of LH2, in particular with current research done at Sandia National Laboratory SNL. The results will help to improve the knowledge base and state-of-the-art, which will be reflected in appropriate recommendations for development or revision of specific international standards.

The main objectives of PRESLHY are to identify critical knowledge gaps and to close these by developing and validating new appropriate models. Based on these results and with the better understanding of the relevant phenomena, specific engineering correlations will be derived which will help to evaluate mitigation concepts and safety distance rules for LH2 based technologies.

The derived models and correlations could be directly implemented in new standards ans/or will fill current gaps in risk assessment tools, like the US supported hydrogen risk assessment toolkit HyRAM, and increase their validated scope of application. In general it will remove over-conservative requirements for innovative solutions, allows for cost-efficient safer design and for internationally harmonised, performance based standards and regulations.

These objectives are fully aligned with European scientific-technological interests and strategies and very important to further the safe introduction and scale-up of hydrogen as an energy carrier.

Duration: 2019 – 2021​.

Funding body: EU​.

Statistics show that fires and explosions are the top cause of Business Interruption loss. Despite increasingly stringent safety measures, explosions continue to occur with higher frequency and consequences especially when Deflagration to Detonation Transition (DDT) occurs. Flame acceleration (FA) and DDT involve complex physical and chemical processes. Current provisions for explosion safety design are based on mechanisms for explosives and insufficient to interpret the complex nature of gas explosions. Their use in safety design is problematic.​

DNS predictions have shown the importance of TF on FA and DDT in uniform mixtures. Such influences are likely to be even more profound in mixtures with concentration gradients and when obstacles are present. There lacks experimental and numerical investigations to shade light on this. Robust and efficient predictive techniques which can capture global safety features associated with FA and DDT as well as TF are also missing. TurbDDT aims to fill these knowledge gaps. It aims to predict FA and DDT in industrial scale explosions incorporating the turbulence effects.

Duration: 2019 – 2021​.

Funding body: Innovate UK​.

The Government's Faraday programme is supporting an important new research project to improve the safety of batteries for use in electric vehicles and as stationary power sources. Businesses Jaguar Land Rover, Denchi Power, 3M, Potenza, Lifeline and Tri-Wall are pooling resources with academics and experts at the University of Warwick and the Health and Safety Executive to ensure public safety in the age of electric motoring.​

Electrically-powered vehicles and battery storage installations thankfully have a good safety record in the UK, but engineers and academics involved in battery design are taking no chances. Lithium-Ion battery cells have the potential to catch fire aggressively, and with consumers demanding that batteries give them further range and faster charging, there is an urgent need to develop an understanding of how such "thermal runaway" (TR) events may be triggered, suppressed and contained. The use of improved prevention materials, methods and mechanisms and a focus on identifying and detecting all early signs of risks, will ensure that fires can be prevented, or if necessary isolated and suppressed before they spread.​

Project LIBRIS seeks to improve understanding of the range of potential causes of TR in individual battery cells and through scaling up tests and scientific understanding, develop better computational models for assessing the spread of TR within battery packs. The team will use real vehicle and stationary Lithium-Ion battery designs and applications to model theoretical work and will take forward the most effective innovations into newly designed packs which will be tested to make sure that the inventions actually work. The group will then use this experience to develop standard tests for assessing the effectiveness of any future battery fire prevention mechanisms, thus assisting the next generation of work on this vital issue.​

The project will lead to better battery pack design and control software, better fire sensing equipment, more use of innovative flame-retardant materials and better packaging for batteries in transport and during storage. It will create business opportunities and investment in the UK, whilst also contributing to public safety. It will also build UK public sector capability to influence future international safety standards and regulations, so that safety remains paramount, but is science-based and not used as an artificial excuse for trade barriers.​

Duration: 2018-2020​.

Funding body: EU​.

The project is aimed at analysing the thermal behaviour and structure response of lithium-ion cells during charge and discharge cycles.

Deformation induced by insertion of the lithium in the electrodes under constraints and high temperatures can generate stresses, which will lead to crack or microfracture of the electrode materials. The advanced smoothed finite element, which is more accurate than standard finite element method for solving thermoelastic problems, will be employed to gain insight about the temperature and stress distributions of cells during charge and discharge cycles.

The fracture of electrode material will be simulated using the phase field model, which is different from discrete fracture and continuum damage models and ideal for dealing with branch crack and multiple crack problems.

Duration: 2018 - 2019​.

Funding body: Innovate UK​.

The Faraday Challenge (FC) Round 2 is designed to support the creation of a viable UK electric vehicle (EV) battery supply chain with an emphasis on safety of lithium ion batteries (LIBs). A major known concern relating to the use, transportation and storage of LIBs is the need to "eliminate _thermal runaway_ risks for enhanced safety". PreLIBS (Preliminary feasibility study into Lithium Ion Battery Safety) aims to develop an understanding of key areas linked to this area. The study will act as a precursor for further research.**​

It is envisaged that the industrial benefits would include:​

• Manufacturers taking Lithium-Ion battery safety responsibly and benefiting from enhanced solutions to address Thermal Runaway and subsequent Thermal Propagation mitigation strategies​
• The ability to predictively model fire propagation would allow the optimisation of solutions -- delivering lighter weight and lower cost without reducing safety​
• Encouragement of an increased uptake of EVs, providing greater efficiencies in use over ICEs
• UK LIB safety testing at HSL would give UK manufacturers an early advantage in taking these technologies to market​.

The PreLIBS team is made up of a consortium with members from Jaguar Land Rover (JLR), Warwick Manufacturing Group (WMG), Health and Executive, Science Division (HSL), Warwick Fire, Potenza Technology, Lifeline Fire and Safety Systems Ltd (Lifeline) and 3M UK PLC (3M); knowledge and expertise would be pooled to navigate the challenge.

A review of existing literature would be conducted with a focus on standards and regulations. Data from a preliminary body of test and modelling work, which would provide initial guidance for sensing and mitigation solutions, considering a variety of potential materials.

Key deliverables from the PreLIBS study would include:**​

• Guidance on navigating and evidence to inform the standards​
• Analysis of sensing and detection methods​
• Evaluation of material effects in thermal runaway​
• Cell and cell group data to inform modelling and material design​.

Industry, including battery manufacturers and organisations using batteries in their products, is actively seeking information about how to integrate battery safety into their products, processes, and procedures. These concerns need to be addressed now to ensure that safety issues do not become barriers to the effective and safe deployment of LIB technology for EVs.​

Duration: 2014 - 2018​.

Funding body: EUJ, Fuel Cell and Hydrogen Joint Undertaking​.

HySEA (Hydrogen Safety for Energy Applications) ran from 2015-2018. It was co-funded through Fuel Cells and Hydrogen 2 Joint Undertaking (FCH 2 JU) – part of the EU’s Horizon 2020 Research and Innovation Programme. The project aimed to improve hydrogen safety through pre‐normative research on vented deflagrations. Consortium partners were GexCon (co-ordinator), University of Warwick, University of Pisa, Impetus AFEA, Fike Europe and Hefei University of Technology.​

Warwick’s unique contribution to this project was the development and validation of simplified engineering models (EM) and computational fluid dynamics (CFD) techniques. Collaborative research resulted in CFD predictions that provided insight into vented hydrogen explosions and the effects of structure response on the over pressure predictions. Such insight along with the large-scale experimental tests conducted by GexCon have assisted the development of the EM for vent panel design for explosion mitigation. The new EM has been published at International Journal of Hydrogen Energy with GOLD OPEN ACCESS.​

Duration: 2016 – 2018.

Funding body: EU​.

The project is aimed at investigating numerically the behaviour of flames ejected from enclosure fires in external facades and other vertical spaces such as atrium, void spaces and staircases.

Full understanding of such external flame behaviour requires insight of the combustion within the enclosure. Hence the scope of the research includes enclosure fires to characterise the ejected flames as well as fire growth in façades.

The research will take advantage of the abundant experimental data available for model validation while the validated predictive tool based on computational fluid dynamics (CFD) techniques will be applied to conduct parametric studies to formulate recommendations for the update of regulatory guidelines to improve fire safety in facades and other vertical spaces.

Duration: 2015 – 2017.

Funding body: EU​.

Lithium-ion batteries (LIB) are found in many applications such as consumer electronics, electric vehicles (EVs) and airplanes. However, they can be dangerous under some conditions and can pose a safety hazard since they contain a flammable electrolyte and are also kept pressurised.

Despite the high safety standards being imposed, there have been many reported accidents and manufacturer recalls. Most accidents can be sourced to runaway reactions, which could happen if the LIBs are overheated or overcharged. This is often accompanied by cell rupture and in extreme cases can lead to ignition, fire and explosions. As an example, the LIB on a Japanese Airline’s Boeing 787 caught fire in January 2013, resulting in FAA grounding all delivered 787 until the overhaul of the problem.

The project aims to deliver a predictive tool, which will be generic across all LIB types for LIB thermal management from the safety perspective. Such a tool can aid the development of safer LIB cells and the optimisation of LIB packs balancing performance and safety requirement. The specific objectives of the research include:​

• Develop and validate a thermal model to predict the onset of runaway reactions;
• Extend the above model to predict potential ignition
• Extend the model to predict possible escalation from cell ignition to pack fire and explosion
• Validate the model with full scale test data giving particular emphasis to cell rupture and the propensity from ignition of a single cell to battery packs
• Conduct cases studies to formulate recommendations on LIB safety.

Duration: 2013 – 2017​.

Funding body: EU​.

This is a collaborative project led by the University of Ulster with University of Warwick and University of Bath as partners. It is funded under the EPSRC SUPERGEN Hydrogen and Fuel Cell Programme.

The research will start with hazard identification study to assess the potential risks involved. Numerical simulations (fire dynamics CFD and structural analysis FEM) will be conducted on the basis of the proposed enhancement of cylinder fire resistance to evaluate the achievable reduction in mass flow rate.

Experimental testing will be undertaken for validation of numerical simulations. Based on numerical and experimental studies the testing protocol for fire resistance of onboard storage tanks will be developed. The research will also include the use of materials efficient for hydrogen storage as a tank liner.

Socio-economical study will crown the project outputs, translating the engineering safety strategies and solutions, such as higher fire resistance, lower mass flow rate through TPRD, shorter separation distance, provisions of life safety and property protection, into economical equivalents, e.g. cost of land use, insurance cost, etc.

The output of this multi-disciplinary project will aim to inform wider public to underpin acceptance of HFC technologies. The project is complimentary to the EPSRC SUPERGEN Hydrogen and Fuel Cells Hub. Collaborators on this project include leading in the field experts and organisations from all over the globe: UK, USA, France, China, Korea.

Duration: 2014 – 2017.

Funding body: EU​.

The main hazard of liquefied natural gas (LNG) is the flammable vapour which can extend to kilometres as a greenhouse gas, or be ignited resulting in fire and explosions.

SafeLNG will focus on six specific areas which are most relevant to facility risk management but for which both theoretical insight and predictive tools are lacking:

• To characterise different LNG release scenarios and develop robust source term models
• To gain insight of the complex physics in LNG/fuel cascades and flammable cloud formation, and develop robust predictive tools
• To develop a robust model for accurate prediction of rollover
• To develop modelling strategies for assessing the environmental impact of large LNG spill by coupling micro scale dispersion models with mesoscale atmospheric models
• To develop and validate LES based predictive tools for large LNG pool and jet fires
• To validate and improve models for explosions in non-uniform LNG vapour mixtures
• The predictive tools to be developed will be validated using published data as well as proprietary data from the private sector Associated Partners, and used to conduct parametric studies as well as safety case studies based on realistic LNG terminal layout.​

The project was an Innovative Doctoral Programme (IDP) funded by the Marie Curie Action of the 7th Framework Programme of the European Union and co-ordinated by Professor Jennifer Wen on behalf of Kingston University where she is a visiting professor.

Duration: 2014 – 2018​.

Funding body: FM Global​.

Various weighted-sum-of-gray-gas (WSGG) models have been implemented in FireFOAM. Further verification and validation of the implemented models will be carried out concerning angular discretization and pool fire predictions. Work is ongoing to address the radiative properties of evaporating water droplets during fire suppression.​

This project built on the earlier projected, also funded by FM Global, tp improve sub-models for combustion and soot in FireFOAM.

Duration: 2013 – 2015​.

Funding body: EU​.

Flame spread is an important topic for addressing fire safety concerns. The project is aimed at developing a fully coupled fluid–solid approach to simulate co-flow flame spread over poly(methyl methacrylate) (PMMA) and corrugated cardboards. FireFOAM, the large eddy simulation (LES) based fire simulation solver within the OpenFOAM® toolbox will be used as the basic framework. Validation will be carried out by comparison of the predictions with experimental measurements over a range of flame spread rates. The validated model will then be used to predict upward flame spread in parallel panels typically used in large scale fire tests.

Development of a fully coupled fluid–solid approach to simulate co-flow flame spread over PMMA and cardboards at different angles of inclination.​

To examine and select appropriate solid pyrolysis models for PMMA and corrugated board, including using latest experimental data to enhance existing models.​

Validation over a range of flame spread scenarios including generic configurations at different scales using primarily PMMA but some latest data using corrugated board typical of warehouse applications.​

The validated model will then be used to predict upward flame spread in parallel panels representative of large scale fires.​

The project will be carried out in collaboration with FM Global. The company will provide technical support as well as data generated using the Flame Propagation Apparatus (FPA) in their Fire Technology Laboratory will be used for model validation.

Duration: 2011-2016​.

Funding body: National Grid​.

National Grid is pursuing plans to transport CO2 through pipelines from the proposed Don Valley Power Project near Doncaster to Saline Aquifers off the Yorkshire coast. There is also an aspiration to develop the first pipeline into a network configuration that links up multiple CO2 emitters in the Yorkshire and Humberside area.

In order to progress the technical work required, National Grid has initiated the dense phase CO2 PipeLine TRANSportation –(COOLTRANS) programme of research to address knowledge gaps relating to the safe design and operation of onshore pipelines for transporting anthropogenic, high pressure, dense phase CO2 from emitters to storage.

A number of large scale experiments have been carried out to gain insight into CO2 behaviour during different release scenarios and to confirm the pipeline toughness requirements in order to prevent running fractures [4-6]. The present study is part of the COOLTRANS research programme. Its specific aim is to develop and validate predictive tools for modelling large scale CO2 dispersion simulations. Such predictive tools will provide quantified information on the CO2 concentrations in the nearby regions following a potential release and hence guide operators to ensure that the pipeline routes will have sufficient safety distances from nearby business premises and residential buildings.

Duration: 2010-2012​.

Funding body: BP​.

A series of projects to model fire, explosions and detonation arrester.

Duration: 2005 - 2009​.

Funding body: EU​.

HYFIRE project offered a unique opportunity for eleven researchers in the early stages of their career to undergo rigorous scientific training and career development in the internationally renowned Centre for Fire and Explosion Studies at Kingston University with the support of major international energy company BP and the United Kingdom Health and Safety Executive’s Health and Safety Laboratory.

The excellent training opportunities have enabled the researchers to develop specific scientific skills and competencies in the diffusion, ignition and combustion of hydrogen within the context of fire and explosion safety.

The project has focused on cutting edge research in the following underpinning areas:

• Hydrogen jet flames from very high-pressure release
• Spontaneous ignition of pressurised hydrogen
• Accidental release of liquid hydrogen jet - flashing, evaporation, the subsequent dispersion and ignition potential
• Hydrogen combustion in semi-confined and vented geometries and the conditions for deflagration-to-detonation (DDT) processes
• Detonation of hydrogen and vapour cloud
• Hazards analysis of small hydrogen leaks in enclosures with limited ventilation
• Flame/wall interaction in hydrogen and hydrocarbon combustion
• Combustion and flammability of hydrogen doped hydrocarbon fuels
• Structure response to blast loading.​

HYFIRE researchers have successfully developed and validated advanced CFD models for the spontaneous ignition phenomenon in pressurised hydrogen release.