基于GIS的有毒气体储罐泄漏扩散及其过程模拟

为动态模拟有毒气体储罐泄漏扩散事故（toxic gas vessel leakage and dispersion，以下简称为TLD）的扩散过程，基于高斯点源瞬时泄漏模型，添加时间因子，将TLD的泄漏过程转换为一系列瞬时点源泄漏的叠加过程，从而获得任意时刻、任意位置的有毒气体浓度分布方程。以某氯气泄漏事故为例，模拟了有毒气体的扩散过程。结果表明，在初始阶段有毒气体储罐泄漏扩散的影响范围是逐步增大的；泄漏持续到一定时间，扩散过程趋于稳定；若假设泄漏条件不变，则此后的扩散过程类似于连续泄漏，影响范围保持不变。经与ALOHA软件的计算结果对比，两者在泄漏5分钟以后的模拟结果基本一致，本文所述模型模拟计算结果可信。

GIS Based Toxic Gas Vessel leakage,dispersion and simulations

Gaussian model have been used to simulate toxic gas dispersion by two typical modes: instantaneous leakage mode or continuous leakage mode. While a high pressure container or vessel breaks, toxic gas will leak and disperse in atmosphere. The concentration of some point at downwind direction will change with dispersion; neither instantaneous leakage mode nor continuous leakage mode can be used to simulate the dispersion. To simulate toxic gas vessel leakage and dispersion (TLD), a method is described. The method derived from Gaussian instantaneous leakage model, introduced time factor, deduced a TLD function. With the function, the effect of TLD is equivalent to the superposition of a series of instantaneous air masses. A case study shown, the affect range of TLD is increased progressively in initial stage; after a certain period of leakage, the dispersion process tends to be stable, the affect range will be changeless under invariable leakage condition and similar with continuous leakage. Compared the result of case study with ALOHA, under similar conditions, the simulation results are identical basically after leakage 5 minutes, so the TLD model is authentic and accurate.