Speaker
Description
To ensure high-quality decision support from risk analyses of systems with explosion hazards, accurate assessment of explosion consequences in realistic scenarios is crucial. Flame acceleration and overpressure development in flammable fuel-air clouds is highly sensitive to the presence of geometry – parameters such as obstacle dimensions, orientation, shape, density and distribution within the flammable cloud can significantly affect the severity of the event. The primary mechanism for flame acceleration in congested areas is the positive feedback between expansion of combustion products, generation of turbulence from obstructions in the unreacted mixture, and enhanced rate of turbulent combustion. To represent explosions in systems of practical interest, consequence models must therefore be able to account for the processes on the scales where the flame front and flow structures interact. Pressure effects from accidental explosions are often studied in the far-field, which can involve systems spanning several hundred meters. Computational fluid dynamics (CFD) models that apply the Porosity/Distributed Resistance (PDR) concept offer a pragmatic method for modelling the effect of complex geometry on the highly transient and three-dimensional physical phenomena in gas explosions. The PDR concept was first adapted for modelling gas explosions by Bjørn H. Hjertager in the early 1980s, as part of his research activities at Chr. Michelsen Institute in Bergen, Norway. In 2025, several CFD models applying the PDR concept for gas explosion modelling exist, both for academic and commercial use. CFD models that use the PDR concept with the Reynold’s Averaged Navier–Stokes (RANS) equations remain the state-of-the-art for assessing explosion loads in the offshore sector. The increase in computational capacity over the last decades allows for more widespread use of CFD simulations for risk assessments in industry and society. This paper reviews the recent advances in modelling gas explosion events with the PDR concept, and discusses how both academic study and the practical application of these models can support the new energy transition. The paper addresses opportunities and challenges, both from a pure modelling perspective as well as implications for the strength of knowledge in risk assessments.
