英语翻译Accidental releases of hazardous gases have been the sub

英语翻译
Accidental releases of hazardous gases have been the subject of studies since the early 1980s and were investigated by the executing trials of large spills and development of numerical models; these models continue to be currently utilized for loss prevention purposes in chemical- and process industries ,and some of them,like DEGADIS,SLAB,ALOHA,and UDM,are among the most popular and widely used models in safety engineering applications.These are lumped-parameter models,usually pseudo one-dimensional,and account for some physical phenomena using semi-empirical relationships whose parameters have been tuned on field test data .Since the experimental setup of these field trials usually does not involve any particular obstacle,these models can provide reliable results only in open field conditions,that is,when almost no obstacles are present in the cloud region.
To analyze the effects of multiple large obstacles on gas dispersion,computational tools based on computational fluid dynamics(CFD) can be utilized to simulate the complex urban geometries involved.This approach enables performing full three-dimensional analysis,and predicting velocity,temperature,and concentration a tracer gas has been also analyzed and the results obtained have been compared using integral models and hybrid models to assess concentrations in fields.However,where atmospheric stability was concerned,only wind-,temperature-,and turbulence profiles were
imposed at the inlet boundary,without verifying whether the turbulence closure model maintains the profiles imposed at the wind inlet boundary throughout the integration field thereby assuring the correct representation of the physical phenomena involved.
In this work,realistic gas dispersion in a geometrically complex environment (i.e.urban terrain) was studied utilizing CFD tools,enabling a full 3D analysis of the effects of the obstacles in the impact area of the hazardous cloud.In particular,as a case study,ammonia dispersion was studied in the Lecco municipality,which is a small city located in a highly industrialized region in the north of Italy.The influence of the atmospheric stability was accounted
for using the ASsM approach [16] which ensures consistency of
the turbulence closure model with the Monin-Obhukov similarity
theory.Moreover,since consequences of toxic gas dispersion
mainly depend on the absorbed dose,a dedicated methodology was
implemented in the CFD code for absorbed dose evaluation.
To represent simply but realistically the geometry of the urban buildings,a dedicated procedure was developed for the reconstructionof the 3D city model from the available topographic database and its direct import into the CFD code,since the realistic representation of all the buildings present in the integration domain represents one of the key problems when urban environments areinvolved.

意外释放有害气体,一直是20世纪80年代初以来的研究课题,并通过大量泄漏和数值模式的发展正在执行的试验研究,这些模型仍然是目前预防目的使用的损失在化工和加工工业,以及其中一些像DEGADIS,板,阿罗哈,和UDM的,是在安全工程应用中最流行和广泛使用的模型.这些都是集总参数模型,通常伪一维,以及使用半经验关系,其一直在现场测试数据优化的参数的一些物理现象的帐户.由于这些田间试验的实验装置,通常不涉及任何特定的障碍,这些模型可以只提供露地条件下可靠的结果,也就是说,当几乎没有障碍,目前在云区.
为了分析气体扩散多个大障碍的影响,基于计算流体力学（CFD）动力学的计算工具,可以用来模拟复杂的城市几何形状有关.这种方法使执行全三维分析和预测的速度,温度和浓度的示踪气体也已进行了分析和取得的成果进行了比较,采用积分模型和混合模型,以评估领域的浓度.但是,当大气稳定度而言,只有风,温度和动荡概况
在当时实行进口边界,没有核实是否湍流闭合模型保持在整个一体化领域,从而保证了所涉及的物理现象,正确的表示风入口边界施加的配置文件.
在这项工作中,在几何形状复杂的环境（即城市地形）实际利用天然气扩散CFD工具进行了研究,使一个充满了危险的云区的障碍,影响效果三维分析.尤其是作为一个案例研究,研究了氨分散在莱科市,这是一个小城市在高度工业化的地区位于意大利北部. ,大气稳定性的影响占
为使用ASSM的方法[16],确保一致性
与莫宁- Obhukov相似湍流封闭模型
理论.此外,由于有毒气体泄漏扩散后果
主要依靠吸收剂量,方法是一个专门
实施了吸收剂量评估CFD软件.
但实际上只是为了表示对城市建筑物的几何形状,有专门的程序制定了reconstructionof从可用的地形数据库的三维城市模型并将其纳入直接进口的CFD软件以来,所有建筑物在融合目前的现实表现,时域代表了城市环境areinvolved关键问题之一.
没译到的单词是拼写有问题