This paper takes a city gas filling station as the research object and builds a three-dimensional computational fluid dynamics numerical model based on flame acceleration simulation software to systematically explore the dynamic law of gas cloud diffusion in the process of urban gas leakage, focusing on revealing the mechanism of urban gas leakage direction and wind field direction on diffusion behavior. By setting a number of contrasting conditions (including due west/due south leakage and multi-directional wind conditions), the evolution characteristics and concentration distribution of gas cloud under different scenarios were analyzed. It is found that the leakage direction has a significant effect on the gas cloud shape in the initial development stage, and the wind field has a significant control effect on the gas cloud diffusion process. On the one hand, it dominates the overall migration direction of gas clouds and expands the diffusion range. On the other hand, to enhance the air convection effect, buildings will hinder the diffusion of gas clouds at the same time, resulting in gas cloud accumulation, and the narrow tube effect formed by buildings cannot be ignored. The results show that the gas cloud diffusion law under the action of multiple factors can provide theoretical support for the design of safety spacing of urban gas filling stations and the optimization of leakage emergency plan and can improve the scientific basis for the emergency rescue decision of urban gas leakage accidents.
Zhang et al. (Tue,) studied this question.