A study of hydrogen dispersion in an open-ended rectangular channel

Hydrogen’s low density and wide flammability range pose significant risks in the event of accidental releases, making understanding its dispersion characteristics crucial for adequate safety measures. The present work investigates the experimental hydrogen dispersion characteristics in a 5.8 m x 0.9 m x 0.8 m open-ended channel with mass flow rates ranging from 0.04 to 1.27 g/s with and without the presence of an obstacle. Twenty-nine hydrogen sensors were used to measure the hydrogen concentration in the air. The experiments are complemented by numerical results using the OpenFOAM® CFD framework, which was published previously. Two distinct dispersion models were identified, dependent on the mass flow rate. For low mass flow rate (low momentum) releases, the dispersion is related to the “filling box” model, resulting in a thin hydrogen cloud, and for high momentum releases, the dispersion is related to the “fading up box” model, characterized by light-fluid intrusion flow. A Froude concentration model that predicts the mean hydrogen concentration in the light-fluid gravity current is presented, which is in good agreement with the experimental results. The results contribute valuable data for validating numerical models. • Experimental and numerical study of hydrogen dispersion in an open-ended channel. • Dispersion of hydrogen from 0.04 to 1.27g/s with a maximum Mach number of 0.72. • Two types of dispersion characteristics related to the “filling box” and “fading up box” model. • A broad range of quantitative data on large-scale hydrogen dispersion well-suited for validating CFD. • Presents a Froude model to determine the hydrogen concentration in the light fluid gravity current.