临近车辆对LNG槽车泄漏扩散规律的影响研究

Study on Influence on Leakage Dispersion Rules of LNG Tanker by Adjacent Vehicle

为降低LNG槽车行驶过程中发生泄漏对临近车辆造成爆炸威胁的可能性,通过CFD数值模拟,研究LNG泄漏在临近车辆周围的浓度分布特征,研究车辆间距等因素对LNG泄漏扩散过程的影响规律。研究表明:在风速2m/s,泄漏孔径0.1m,LNG泄漏口下风向10、20、30m处,空间内甲烷气云的流动状态和浓度分布趋势基本保持不变,泄漏口轴心处甲烷气体流速最高并向周围依次递减;临近车辆的阻挡作用使得高浓度甲烷气云积聚于车头处,随着临近车辆间距的增加,其后方出现回流,流场分布形态更加紊乱,易出现甲烷气云积聚现象;LNG槽车与临近车辆间距为30m且泄漏10s内,临近车辆周围的甲烷气云浓度低于爆炸下限,建议后方车辆宜与LNG槽车保持30m以上的安全距离。

In order to reduce the explosion possibility caused by the leakage during the travelling of LNG tank truck,in this paper,through the CFD(computational fluid dynamics)numerical simulation,the concentration distribution characteristics of the LNG leakage around nearby vehicles was analyzed and the influence rules of factors such as vehicle spacing on the LNG leakage diffusion were researched.The results show that with a wind speed of 2m/s,a leakage orifice diameter of 0.1m,and at downwind distances of 10m,20m,and 30m from the LNG leakage point,the methane gas cloud s flow state and concentration distribution trends remain basically stable,and the methane gas flow speed is highest at the axis of the leakage point and gradually decreases outward;that the blocking effect of nearby vehicles causes high-concentration methane gas clouds to accumulate at the front of these vehicles,and as the distance between the nearby vehicles increases,a backflow appears behind them,leading to a more chaotic flow field distribution and a higher likelihood of the methane gas cloud accumulation;and that when the distance between the LNG tank truck and the nearby vehicle is 30m and the leakage lasts within 10s after leakage,the methane gas cloud concentration around the nearby vehicle remains below the lower explosive limit of the methane.Therefore,it is recommended that following vehicles maintain a safety distance of more than 30m from the LNG tank truck.