Numerical simulation study on propane gas leakage and diffusion law in slope terrain

Abstract It is frequent that gas leakage accidents occur at chemical enterprises located in slope terrain. Meet the requirement of urgently studying the gas leakage and diffusion law in slope terrain. In this study, we utilize computational fluid dynamics (CFD) to simulate the scenarios of propane leakage and diffusion under four distinct slope conditions, which are 0°, 10°, 15°, and 20°. The gas diffusion law under different slopes is investigated, and the influence of wind speed and wind direction on the diffusion process is also further analyzed. The study indicates that when the slope exceeds 15°, the change in slope exerts a pronounced influence on the dispersion of propane leakage. Compared with diffusion on flat ground, there is a distinct propane aggregation area at the bottom of the slope terrain. Also, the steeper the slope, the more noticeable the aggregation phenomenon. The increase of wind speed makes propane gas lifted, and the gas aggregation at the bottom of the slope decreases. In particular, at a wind speed of 3.3 m/s, the aggregation of propane at the bottom of the first 15° and 20° slopes is more pronounced. Under the upwind condition, the propane gas is entrained at the slope surface, increasing the propane concentration in the area around the tank, which in turn increases the safety risk. The findings of this study have significant implications for the rational layout of chemical enterprises, gas leakage monitoring, and emergency evacuation planning for leakage accidents. They can also help enhance chemical enterprises' safety prevention abilities and the efficiency of their emergency response.