Impact of Mechanical Ventilation on Build-up and Concentration Distribution Inside a 1-m3 Enclosure Considering Hydrogen Energy

Natural ventilation is an efficient and well-known way to mitigate a hydrogen build-up in the case of an accidental release in confined enclosures. However, for some hydrogen energy applications, natural ventilation is not possible or is not efficient enough to reach defined safety strategy. Thus, mechanical or forced ventilation can be interesting means to avoid critical concentration of hydrogen considering degraded operation and associated potential hazardous events. To better understand the impact of mechanical ventilation on the hydrogen build-up and distribution, a dedicated study was led. First, accidental release scenarios were experimentally simulated with helium in a 1-m3 enclosure. Several configurations of release and ventilation modes were tested, and are presented in this study. Secondly, analytical and numerical – Computational Fluid Dynamics – calculation approaches were applied and adjusted to propose a simplified methodology, taking into account mechanical ventilation for assessment of hydrogen accumulation and for design optimization of the applications.