Simulated hydrogen concentration in a 1 m³ ventilated enclosure for two nozzle sizes and three release rates.

CFD consequence analysis for hydrogen and net-zero-carbon fuels

CFD (Computational Fluid Dynamics) simulations show where a fuel goes during a leak, how much accumulates and how quickly. RISE uses experimentally validated CFD simulations to assess the consequences of leaks of hydrogen and other net-zero-carbon fuels early in design.

Introduction

Hydrogen, ammonia and e-methanol are entering ships, vehicles, buildings and energy systems. A leak in an enclosed space can build up to hazardous levels. Hydrogen rises quickly but can still form a flammable layer beneath the ceiling.

Large-scale release tests are costly and cover few scenarios. CFD can study many leak rates, locations and ventilation layouts at a fraction of the cost, and shows the entire gas cloud. Our simulations are validated against experiments, and the case setups are openly available on GitHub and Zenodo.

Validated against experiments

We validated the general-purpose open-source CFD code OpenFOAM against 18 published hydrogen release experiments from CEA, France (Bernard-Michel and Houssin-Agbomson, 2017). The experiments cover two enclosure volumes (1 m³ and 2 m³), two nozzle sizes, and releases ranging from slow plumes to high-momentum jets.

The predicted ceiling hydrogen concentration differs from the measurements by at most 1.2 vol% in the 1 m³ enclosure and 0.6 vol% in the 2 m³ enclosure. Sensitivity studies on mesh and turbulence modelling, and a clear account of the method's limits, show when results can be used directly and when a safety margin is needed.

Huang, C.; Dahlbom, S.; Gehandler, J.; Arymbayeva, A. Benchmarking Hydrogen Dispersion CFD Simulations Using OpenFOAM. Energies 2026, 19(20), 4930. https://doi.org/10.3390/en19204930 (open access)

This work was funded by the European Union's Horizon Europe research and innovation programme under grant agreement No 101192425 (NAVHYS).

What we offer

Complex geometries: simulations built directly from CAD models of real installations, including equipment, ducts and openings
Gas dispersion and accumulation: how a leak spreads and how large the flammable or toxic zone becomes
Ventilation: sizing and placement of natural or mechanical ventilation
Gas detector placement: where sensors detect a leak fastest
Hazardous area classification: CFD support for the extent of ATEX zones
Scenario studies and test planning: many cases can be simulated before costly experiments are carried out
Independent review of third-party CFD studies

How we work

Collaborative research: CFD hazard simulation and validation in European and national projects.
Commissioned studies: consequence analyses for companies and authorities, from a single design check to full scenario studies.
Across RISE: simulation support for colleagues working on gas-release questions.

Applications

Ships: fuel-cell rooms, tank connection spaces, bunkering
Vehicles in garages, tunnels and on ferries
Refuelling stations, electrolysers and storage containers
Hydrogen use in buildings and industry

Want to know more?

Are you planning a hydrogen installation, assessing a design or preparing a research proposal? You are very welcome to contact us to discuss how simulations can support your work.