Detailed Assessment of Dispersion for High-pressure H2 in Multi-fuel Environment

The MultHyFuel project notably aims to produce the data missing for usable risk analysis and mitigation activity for Hydrogen Refuelling Stations (HRS) in a multi-fuel context. In this framework, realistic releases of hydrogen that could occur in representative multi-fuel forecourts were studied. These releases can occur inside or outside fuel dispensers and they can interact with a complex environment notably made of parked cars and trucks. This paper is focused on the most critical scenarios that were addressed by a sub-group through the use of Computational Fluid Dynamics (CFD) modelling. Once the corresponding source terms for hydrogen releases were known, two stages are followed:
♦ Model Validation – to evaluate the CFD models selected by the task partners and to evaluate their performance through comparison to experimental data.
♦ Realistic Release Modelling – to perform demonstration simulations of a range of critical scenarios.
The CFD models selected for the Model Validation have been tested against measured data for a set of experiments involving hydrogen releases. Each experiment accounts for physical features that are encountered in the realistic cases. The selected experiments include an under-expanded hydrogen jet discharging into the open atmosphere with no obstacles or through an array of obstacles. Additionally, a very different set-up was studied with buoyancy-driven releases inside a naturally ventilated enclosure. The results of the Model Validation exercise show that the models produce acceptable solutions when compared to measured data and give confidence in the ability of the models, and the modellers, to capture the behaviour of the realistic releases adequately. The Realistic Release Modelling phase will provide estimation of the flammable gas cloud volume for a set of critical scenarios and will be described at the second stage.