Validation and recommendations for FLACS CFD and engineering approaches to model hydrogen vented explosions: Effects of concentration, obstruction vent area and ignition position

• Comparison of the prediction models with H2 vented explosion experiments.
• Global good agreement between models and experiments.
• Proposal of recommendations for FLACS use in vented explosions cases.

Explosion venting is commonly used in the process industries as a prevention solution to protect equipment or buildings against excessive internal pressure caused by an internal explosion. In practical cases, for instance in the presence of complex 3D obstructions or for stratified flammable mixtures, analytical engineering models fail. At the opposite, for simple situations, engineering models are sufficient and could give an immediate estimation of the overpressure generated. As a consequence, CFD and engineering are two complementary solutions but they have to be carefully validated. This article is dedicated to the validation of FLACS CFD code and an engineering tool for the modeling of vented explosions by comparison with recent published experimental results. Recommendations and good practices are suggested for the applications of both FLACS CFD and engineering models.