Analysis Methodology for Hydrogen Accident Scenarios in Complex Industrial Environments

This paper describes a general analysis methodology which was developed for consistent and mechanistic modeling of hydrogen behavior in complex industrial accident scenarios. The methodology includes four steps: 1. Three-dimensional CFD simulation of the time and space dependent hydrogen concentration in the computational domain. 2. Application of experiment-based criteria which allow to estimate the fastest possible combustion regime for the given H2-air-distribution and geometrical constraint. 3. Numerical simulation of the identified combustion regime with a validated 3D combustion code; output from this step are mechanical and thermal loads to surrounding structures. 4. Consequence analysis with respect to a) structural response of the pressure loaded building using 3d-FEM or simpler models and b) health effects on persons. As an example for the analysis procedure the blow-down of 31 kg of hydrogen from a large electrical generator located in a 160,000 cubic meter turbine hall is modeled. Temporal evolution of the H2-distribution, the related hazard potential, the turbulent H2-air deflagration and the resulting loads to the building are calculated. Finally possible mitigation measures are derived for the investigated scenario.