Abstract: The risk from the leakage and dispersion of heavy gas is much more serious than that of light gas due to the existence of heavy gas effect. A multi-source dispersion model of heavy gas was developed on the basis of a single SLAB model. And the dispersion behaviors of single and multi-source heavy gas at the mode of continuous and instantaneous leakage were simulated. Then, with a case study of chlorine, the downwind time-averaged concentration distribution under corresponding conditions was calculated. Further, combined with the toxicity criteria, the accident-affected areas at different toxic levels were presented to provide theoretical guidance for emergency rescue and evacuation decision-making.

Key words: heavy gas dispersion, SLAB model, multi-source, continuous leakage, instantaneous leakage