2022 FLUG Meeting registration is now open

The 2022 FLUG Meeting provides an opportunity for users of FLACS-CFD and Gexcon to share updates, insights and experiences.

The event consists of presentations that spark inspiration, encourage dialogues and drive new solutions to process safety challenges and further improve the software by considering user needs.

FLUG has played an integral role in the development of Gexcon’s industry-leading software, which represents more than 40 years of extensive and unrivalled modelling and validation work.

Day 1 | Monday, 31 October 2022

10:00 CET

The direction of FLACS-CFD

Dr Chris Coffey, VP Products @ Gexcon

Gexcon shares its vision and roadmap for FLACS-CFD, providing insights into exciting new features in the pipeline.

12:00 CET

New UX of FLACS-CFD

Dr Chris Coffey, VP Products @ Gexcon

Dennis Lennard @ Creative Navy

An interactive session where we invite your feedback on the planned interface improvements to FLACS-CFD.

14:00 CET

New mesh geometry handling in FLACS-CFD

Djurre Siccama, Senior Manager @ Gexcon

Gexcon presents the work that has been done so far on the new mesh geometry handling in FLACS-CFD.

16:00 CET

New detonation modelling in FLACS-CFD

Olav Roald Hansen, CEO & Founder @ HYEX Safety AS

Lorenzo Mauri, Principal Research Engineer @ Gexcon

You will be presented with the new detonation modelling in FLACS-CFD.

Day 2 | Tuesday, 1 November 2022

10:00 CET

Consequences analysis of thermal runaway of lithium battery-powered vehicles on ro-ro ships

Cao Jiaolong, Senior Engineer @ Wuhan Rules & Research Institute, China Classification Society

With the increasing demand for sea transportation of lithium battery-powered Vehicles, Current fire-fighting measures for car ro-ro ships based on gasoline leakage can it be satisfied the risks caused by high-temperature and light-weight flue gas generated by the thermal runaway of lithium batteries.

In order to solve such problems, FLACS-CFD is used to model and analyze multi-scenario consequence simulations for different ventilation layouts, leakage locations, and the number of leakage points. Based on the simulation results, suggestions are made for the existing fire-fighting measures.

12:00 CET

Is ventilation your trustworthy old friend when it comes to hydrogen?

Pablo Giacopinelli, Senior Engineer – UK FLACS-CFD Technical Lead @ Gexcon

Hydrogen is poised to become a pillar in the transition towards a more sustainable energy system. As a result, many governments, businesses, and research institutions are looking to use hydrogen as an alternative to natural gas, in particular for power and transport applications (gas turbines, hydrogen fuel cells and hydrogen combustion engines).

Although the industry has extensive experience in using hydrogen as part of manufacturing processes, many new applications require hydrogen to be deployed close to the public. However, there seems to be a lack of awareness, particularly among new entrants, of the very different properties and explosion characteristics of hydrogen compared to natural gas.

One crucial difference is the difficulty that typical ventilation systems have in diluting a hydrogen leak to concentrations below which no damaging overpressure is expected. In natural gas applications, ventilation is a well-established component of the “basis of safety” in enclosures (compressor shelters, gas turbines). However, when using hydrogen, ventilation alone might not be enough to achieve a non-flammable atmosphere. This paper will present examples of hydrogen leak dispersion in enclosures and the potential explosion overpressures that could be expected.

We will show the influence of the size of the gas cloud on the severity of the explosion and the effect of different ventilation arrangements. Possible mitigation strategies will then be presented, to enable the safe deployment of hydrogen in applications that require close proximity to the public.

14:00 CET

Jack Rabbit III project on ammonia dispersion modelling

Dr Simon Gant, Technical Fellow @ HSE Science and Research Centre

Lorenzo Mauri, Principal Research Engineer @ Gexcon

Dr Shona Mackie, Senior Research Engineer @ Gexcon

You will be presented with the work from the Jack Rabbit III project on modelling ammonia dispersions.

16:00 CET

LNG model evaluation protocol

Dr Filippo Gavelli, P.E., Consultant @ Blue Engineering and Consulting Company

Every LNG project that is proposed to be built, expanded or significantly modified needs to meet the siting requirements of the applicable regulations, which aim at ensuring the safety of the public and public property in the event of accidents within the LNG plant.

In order to quantify the hazard footprints for potential accident scenarios (such as flammable vapor dispersion, pool and jet fires, vapor cloud explosions, etc.), computational tools must be used. Given the multiplicity of modeling tools available to perform siting studies, regulators are often faced with potentially conflicting results and need to be able to understand which results they can trust. For this reason, a Model Evaluation Protocol (MEP) was developed in 2007 to allow computational tools for vapor dispersion modeling to be reviewed. This protocol was then successfully applied to two software packages (Phast and FLACS-CFD), which were found acceptable for LNG vapor dispersion modeling under US federal regulations.

The 2007 MEP, however, is very limited in scope: in fact, it only addresses vapor dispersion modeling and, more specifically, only from atmospheric releases (e.g., vapors from a liquid spill onto the ground). This means that there are currently no established protocols to evaluate models to simulate hazards such as the flammable or toxic dispersion of a vapor cloud from a pressurized release (e.g., a pipe breach), the overpressures generated by a vapor cloud explosion, etc.

Blue Engineering and Consulting and the Gas Technology Institute are collaborating on a DOT-PHMSA sponsored research project to develop a new set of Model Evaluation Protocols, that will allow the review of modeling tools for each of the above-referenced hazards. The new MEPs will greatly increase the confidence of authorities as well as the public, by defining which models may be used and under which limitations, and what validation factors need to be applied depending on the type of hazards being evaluated.

As of now, MEPs have been completed for flammable and toxic dispersion, and the MEP for source term models is nearing completion. The presentation will provide a summary of the completed MEPs and an outlook towards the remaining work.

Day 3 | Wednesday, 2 November 2022

10:00 CET

Numerical study on helium dispersion and ventilation in a semi-enclosed channel with FLACS-Hydrogen

Hengrui Liu, Postdoctoral Researcher @ UNSW | Research Assistant @ Macquarie University

Hydrogen, as an energy source or as energy storage, is a key pathway for achieving net-zero targets. However, to support the safe usage of hydrogen at large scales, further investigations on hydrogen leakage should be pursued. Leakage of gaseous hydrogen, especially in confined spaces, can lead to catastrophic outcomes such as uncontrolled fire and explosion.

The current study presents a set of measurement and CFD data to understand the dispersion of leaked light gas in a semi-confined space to support the adoption of hydrogen. A dispersion chamber with dimensions of 4×0.3×0.3m3 was constructed to investigate a baseline gas leakage scenario. In the experiment, hydrogen gas was substituted with helium gas to reduce risk since they have similar properties.

To model the dispersion of leaked helium, FLACS-CFD is employed, which is a popular computational fluid dynamics code for risk and safety analysis. The result shows that a good agreement between experiment and numerical data has been achieved, which confirms the accuracy of the model, as well as the suitability of the measurement data. The current results will be useful to further enhance the understanding of hydrogen safety aspects.

12:00 CET

CO₂ dispersion modelling

Stian Jensen, Senior Principal Engineer @ Aker Solutions

Summary of recent work conducted by Aker Solutions on the topic of CO₂ dispersion modelling:

• Aker Solutions take on modelling dispersion from supercritical/ liquid CO₂
• Comparison of CFD results with experimental data
• Example from projects
• Challenges and list of things we would like to see improved in FLACS-CFD

Day 4 | Thursday, 3 November 2022

10:00 CET

Numerical study of hydrogen leakage, diffusion, and combustion in an outdoor parking space under different parking configurations

Yahao Shen, PhD Student @ Tongji University

As the number of hydrogen fuel cell vehicles (HFCVs) being used is increasing, confirming that their safety level is the same as that of gasoline vehicles is becoming important. HFCVs are commonly parked in outdoor spaces. Thus, the safety of HFCVs in garage scenarios should be ensured, and related regulations, codes, and standards for preventing accidents must be developed.

In this study, the Flame Acceleration Simulator (FLACS-CFD) software was utilized to evaluate the behaviour of hydrogen release, dispersion, and flame propagation in the presence of multiple HFCVs in an outdoor parking space through the activation of thermally activated pressure relief devices (TPRDs).

The effects of different leak diameters (2, 3, and 4 mm), release directions (upward and downward), and parking configurations (vertical and parallel) on the formation of a flammable gas cloud (FGC) and safety distances were examined, by considering tank blowdown.

The results showed that larger TPRD diameters resulted in a larger envelope of the FGC; however, it also dissipated faster in outdoor parking spaces. Compared with the vertical parking configuration, the fire-origin HFCV had less impact on adjacent vehicles in the parallel parking configuration.

The direction of an upward release was found to contribute to a decrease in the volume of the FGC in outdoor parking spaces owing to low congestion. This study highlights the significance of the TPRD diameters and parking configurations, providing guidance for the safe introduction of HFCVs in existing outdoor parking spaces and infrastructure.

12:00 CET

Combustion modelling of hydrogen in FLACS-CFD

Melodía Lucas Pérez, Research Engineer @ Gexcon

Gexcon presents the improvements we are working on to reduce conservatism in hydrogen combustion modelling.

14:00 CET

FLACS-CFD user feedback session

Gexcon Software representatives

A session dedicated to FLACS-CFD users where you will have the opportunity to voice their ideas and feedback to improve the software further.

16:00 CET

Can we fly safely on liquid hydrogen? Using advanced modelling tools to understand the hazards

Dr Karina Almeida Leñero, Energy Transition Technical Lead @ Gexcon

In this presentation, Dr Leñero will discuss how advanced modelling using CFD can be used to understand the hazards from potential LH2 release scenarios while refuelling an aircraft and demonstrate how FLACS-CFD can be used to simulate liquid hydrogen spills and their subsequent consequences (gas dispersion, fire, explosion).

These results can then be used to answer questions and provide guidance on issues pertaining to the location and layout of hydrogen refuelling “hubs” at airports, exclusion zones while refuelling aircraft, procedures for refuelling, and appropriate emergency response in case of an accidental release of hydrogen.  

The speakers