Abstract
The main purpose of this paper is to examine the phenomena when hazardous dense gases, such as ammonia gas and LNG, are spilled into the atmosphere from a pressurized storage tank. This study is useful to develop an accidental risk assessment method. The characteristic of gases released from the pressurized tank is a mixture cloud of gaseousness and droplets. In papers published in the past, the effect of evaporation of liquid droplets has never been examined. In this paper, we propose a two layer box model in order to predict a concentration considering this effect. This model is useful to estimate concentration of dense gas released instantaneously from a pressurized tank. Furthermore, for continuous dense gas spill, we calculated the average concentration at the downwind distance, treating the two layer box model like puff models. Also, we improved it to be able to predict the vertical concentration distribution, which was not estimated in the conventional model. The calculated result in this model generally corresponds well with the data of the Desert Tortoise Experiment.
