Consequences assessment of an accidental toxic gas release through a cfd tool: Effect of the terrain and major obstacles

The main aim of this study is the establishment of a new methodology for the assessment of terrain and structures geometry effects on gas dispersion. Significant obstacles (such as the plant structures, buildings, or the terrain elevation) play a major role in gas dispersion, due to the eddies, wakes, stagnation and recirculation points they can introduce. A comparison between CFD simulations and integral model predictions have been worked out for a realistic case-study in order to point geometry role in gas dispersion. Moreover, obstacles and terrain geometries are often not available in a suitable format. The proposed methodology uses easy-accessible data (such as SRTM data and geo-referenced aerial photography) to work out the required inputs, to reduce the time and cost associated to CFD modelling and make it practically applicable in industrial cases (design of new installations or assessment of existing ones).