The role of CFD analysis in studying hydrogen explosions with flame propagation direction changes

National Institute for Research and Development in Mine Safety and Protection to Explosion – INSEMEX, Romania

^* Corresponding author: bogdan.simon@insemex.ro

Abstract

This study focuses on the transition from physical experimentation to virtual simulation, using Computational Fluid Dynamics (CFD) to analyses hydrogen-air explosions conducted in a transparent, rectangular-spiral test stand. The test stand was specifically designed to guide the explosion process along a spiral trajectory with 90-degree turns, aiming to replicate complex flame propagation behavior in confined geometries. The inner volume of the spiral was divided by four thin-film diaphragms, creating four sequential combustion chambers. This configuration allowed for controlled initiation and propagation of the explosion, enabling detailed observation of flame front behavior and the measurement of overpressure and flame speed across chamber transitions. The CFD analysis serves a dual purpose, to compare the explosion parameters obtained through virtual simulation with those recorded in physical experiments, and to calibrate the empirical input values required by the ANSYS Fluent solver for accurately modelling chain-reaction explosions in geometries with directional changes. The study emphasizes the importance of CFD in understanding flame dynamics in complex configurations, supporting both safety analysis and predictive modelling in hydrogen-related applications.