Comparison of CFD numerical approaches for the simulation of accidental gas release in energy applications

Oil & Gas plants are risk-relevant complex facilities for the presence of toxic, flammable and pressurized fluids. Risk assessment is mandatory to guarantee plant sustainability and compliance with directives. For offshore plants characterized by congested spaces, semi-empirical models for accident consequence simulation often result in risk overestimation. This could be avoided through Computational Fluid Dynamics (CFD), which guarantees more accurate results. Complex phenomena and geometries, however, entail large computational efforts that force limiting the number of simulations to explore the accident scenarios. This calls for new approaches able to model and simulate complex congested geometries in affordable time, while achieving keeping the required accuracy of the results. In this context, a novel CFD model based on ANSYS Fluent, named SBAM (Source Box Accident Model), has been proposed by the research group of the SEADOG lab in Politecnico di Torino with the aim of simulating complex environments with good accuracy and reduced computational cost. In this work, the results provided by the SBAM model on an accidental high pressure flammable gas release in a platform, are compared with those provided by other tools and models available in the market, and widely used in industrial applications, such as FLACS developed by Gexcon US and KFX developed by DNV-GL.