Politecnico di Milano, Dipartimento di Chimica, Materiali e Ingegneria Chimica Giulio Natta, via Macinelli 7, 20131 Milano, Italy.
J Hazard Mater. 2010 Apr 15;176(1-3):589-96. doi: 10.1016/j.jhazmat.2009.11.070. Epub 2009 Nov 17.
Release of hazardous materials in urban areas is a major concern in industrial risk assessment. The presence of high population density in such areas multiplies the magnitude of the consequences. In urban areas, many buildings with complex geometries are involved leading to 3D flow fields that strongly influence gas dispersion. Representing such complex geometries simply but realistically in detailed simulation models can be cumbersome and often limit their utility. In this work, a methodology for the construction of 3D urban models and their importation into CFD models was developed through the access to spatial geodatabases, leading to a relatively fast and simple domain design technique. Moreover, since the magnitude of consequences depends on the absorbed dose which in turn depends on both concentration and exposure time, a simple methodology for dose evaluation was developed and implemented in a CFD code that enables the estimation of regions with a given death probability. The approach was developed and applied to a case study with different atmospheric stratification conditions. The results were then compared with those obtained using integral models. It was found that integral models can both overestimate and underestimate the magnitude of consequences related to hazardous material releases in urban areas.
在工业风险评估中，城市地区危险物质的释放是一个主要关注点。在这些地区，由于人口密度高，后果的严重程度会成倍增加。在城市地区，涉及许多具有复杂几何形状的建筑物，导致强烈影响气体扩散的 3D 流场。在详细的模拟模型中简单但真实地表示这种复杂的几何形状可能很麻烦，并且经常限制它们的实用性。在这项工作中，通过访问空间地理数据库，开发了一种用于构建 3D 城市模型及其导入 CFD 模型的方法，从而实现了相对快速和简单的域设计技术。此外，由于后果的严重程度取决于吸收剂量，而吸收剂量又取决于浓度和暴露时间，因此开发并在 CFD 代码中实现了一种用于剂量评估的简单方法，该方法能够估计具有给定死亡率的区域。该方法已开发并应用于具有不同大气分层条件的案例研究。然后将结果与使用积分模型获得的结果进行了比较。结果发现，积分模型既可以高估也可以低估与城市地区危险物质释放相关的后果的严重程度。
