Consequence analysis of accidental gas leak from storage tank group using LES method

Abstract

Hazardous clouds and toxic zones resulting from gas leaks from storage tanks in chemical plants present immediate threats to environmental health and industrial process safety. However, the fluctuation characteristics and fluctuation-induced consequence variations received limited attention. This study employed the large-eddy simulation (LES) to address the time-averaged and dynamic characteristics of consequences associated with gas leaks from a tank group, focusing on the impacts of leak locations and wind directions. Four metrics were introduced to quantify consequences: volumes of flammable and toxic gas clouds (V_F, V_T), toxic zone area (A_T) and toxic dose for population (TD). The results indicated that the Reynolds-averaged Navier–Stokes model (RANS) markedly overestimated the mean values of these metrics compared to LES, with the prediction of AT even increased by 147.5%. The leeward leak from the rear-row tank presented the highest mean and peak values. Both the peak and mean values were generally higher when the wind direction ($\theta$) was 0°, except for TD. Moreover, AT and TD were significantly impacted by pulsating flow, with fluctuation-induced components generally reaching 30%–40%. When $\theta \le 0°$, A_T was primarily influenced by pulsating flow rather than mean flow. The results provide guidance for the design of chemical industrial parks, ensuring the industrial processes safety and refining emergency response strategies.