液化和压缩气体半球形扩散模型集的构建和应用

国内外液化和压缩气体的泄漏爆炸事故屡见不鲜,针对其性质和短时间近地面扩散的特点,总结、修正和扩展了瞬时泄漏下的平均半球形扩散模型。对于连续泄漏,利用数学积分理论建立了静风下的半球形扩散模型。接着对有风时的情况进行建模推导,将风速和气体自身扩散速度进行矢量合成,得到了半椭球形扩散和半椭圆锥与1/4椭球体组合扩散下气体的质量浓度和质量浓度变化趋势。最后用实例验证了该模型的先进性。该模型集能较好地反映液化和压缩气体泄漏后不同泄漏情况、时间、近地面区域和风速下的扩散浓度空间分布及其动态变化过程,为事故后果预估和应急救援决策提供参考。

Establishment and application of hemispherical diffusion model sets for liquefied and compressed gas

The article is aimed at introducing its experience on the establishment and application of the hemispherical diffusion model sets for the liquefied or compressed gas while taking into consideration the conditions of the weak wind and strong wind based on the vector synthesis of wind speed and gas diffusion speed.We have worked out the gas concentration and its changing trends in the semi-elliptical diffusion and the combined diffusion in a semi-elliptical conical and 1/4 ellipsoid manner.As is known,there have been so many leak and explosion accidents of liquefied and compressed gas both at home and abroad,thus causing huge casualties,property damages and environmental pollutions.Nevertheless,little has been seen of the highly qualified researches both at home and abroad as to the leakage and diffusion models,for most of such researches are merely confined in the instantaneous leakage,the static wind and the same concentration in the hemisphere.Seeing the current inadequacy in the research area,we would like to take into a careful consideration the nature of liquefied and compressed gas,their diffusion characteristics and the reality of concentration distribution at the short breaks of time near the surface ground,so as to summarize,revise and improve the currently existing hemispherical diffusion models ofinstantaneous leakage.For instance,it is of great need to study the conditions of temperature and pressure,revise the cubic expansion coefficient of liquefied gas leakage and then to innovate the computational method of gas volume of compressed gas leakage,etc.Therefore,it is also urgent to verify the feasibilities of the models through enough well-selected examples.The model sets we would like to propose should be able to reflect the particular features of the spatial distribution and dynamic changes of liquefied and compressed gas concentration at different leakage processes,temperal and spatial circumstances with the wind speeds well defined,so as to provide a valuable reference for the advanced accident-prediction and forecast and decision-making,rescue-measures preparation and emergency and consequence management.