共查询到20条相似文献,搜索用时 15 毫秒
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应用流体力学基本原理,导出了烟流扩散新模式,讨论了利用照相法估算烟流污染物浓度的方法及步骤,以高架点源烟流扩散为例,应用新模式结合照相法估算烟流污染物浓度,并与利用高斯模式计算的烟流污染物浓度进行比较,结果表明两者吻合较好. 相似文献
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A. Heil B. Langmann E. Aldrian 《Mitigation and Adaptation Strategies for Global Change》2007,12(1):113-133
Numerical modelling of fire-related smoke haze episodes in Southeast Asia is important for both prediction and assessment of atmospheric impacts, especially when observational data are fragmentary, as is the case in Indonesia. This work describes the atmospheric fate of smoke particles emitted during the 1997 Indonesian fires modelled with a regional atmospheric chemistry model. We established a new fire emission inventory and calculate that 55 teragram (Tg) of particulate matter and 1098 Tg of carbon were released during this fire episode. Our emission estimate is an intermediate value compared with other studies. Utilising different scenarios, we demonstrate the variable atmospheric impacts of surface vegetation fires and peat soil fires separately and also investigate the sensitivity of smoke dispersion to the differing meteorological conditions of an El Niño and a normal year. When peat fires are included in the emission inventory, modelled ambient particle concentrations exceed the ambient air quality standard across transboundary scales. In a scenario including only surface vegetation fires, ambient air quality standards are exceeded only in areas close to the main fires. This scenario demonstrates the prominent role of fires in peat areas in causing regional air pollution episodes. In years with normal meteorological conditions, intermittent precipitation and associated wet deposition during the dry season are predicted to remove most of the particulate emissions close to the sources. Strongly reduced rainfall and generally stronger southeasterly winds during El Niño years provide favourable conditions for larger scale smoke haze pollution. 相似文献
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对熏烟扩散模式应用的探讨 总被引:5,自引:0,他引:5
工程上应用的大气污染物扩散模式中 ,熏烟模式由于其非定常性而与其他扩散模式有很大的区别。正确处理模式中各参数及变量的相互关系才能客观地反映污染物对环境影响的结果。本研究通过对熏烟模式的非定常性和各参数、变量相互关系的分析 ,提出了正确使用该模式的方法 相似文献
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基于焦炉炉头烟扩散过程的分析研究,提出栅网状抽吸面以及侧吸式抽吸结构的炉头烟集尘罩结构,并通过计算机仿真的方法进行分析。结果表明:栅网结构的抽吸形式增加了有效抽吸面积,优化了抽吸风量分布,解决了传统集尘罩有效抽吸截面小及风量分配不合理的问题;集尘罩前端的侧吸式抽吸结构,对沿顶板向两侧扩散烟气形成一种侧吸的效果,解决了炉头烟在冲击导烟板后向两侧排放的问题;优化后集尘罩结构,在风机风量降低30%时,依然能够对焦炉炉头烟实现有效治理,提高了集尘设备的运行效率。 相似文献
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《Atmospheric Environment. Part A. General Topics》1990,24(9):2447-2455
A three-dimensional higher-order closure dispersion model is presented. The model is used to simulate dispersion from point sources in complex terrain. The model uses mean and turbulence quantities simulated with the fluid dynamic model presented in Part A to simulate dispersion in a polar coordinate system with its origin in the point source. Different turbulent length scales are used for the vertical and horizontal fluxes. Simulation results are compared with data from tracer experiments performed in southern Sweden, the Vänersborg-Trollhättan region. The tracer experiments were performed during convective atmospheric conditions as well as during very stable conditions. The geographical area has terrain features that exert forcing on the meso-γ-scale. Within the area there is a relatively flat agricultural area, forested hills, a river valley and an extended lake area. The terrain height relief is typically 80 m.The simulations with the dispersion model performed in the Vänersborg-Trollhättan region show good agreement with measured data in the region for convective atmospheric conditions as well as for very stable conditions. 相似文献
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《Atmospheric Environment. Part A. General Topics》1992,26(3):485-495
The dispersion of a passive line source in the convective atmospheric boundary layer is calculated with a large-eddy simulation. The results of the calculation are presented in the form of dispersion parameters. The total dispersion parameter is made up of two contributions: meandering and relative diffusion. Both contributions are calculated as a function of diffusion time and of source height. The results for vertical dispersion show that initially the contribution by meandering is large. Furthermore, the meandering component becomes larger as source height increases. These results can be interpreted in terms of the well-known looping plume in the convective boundary layer. The horizontal dispersion parameter is also influenced by meandering. However, in this case the lowest source has the largest meandering component. Finally, we consider the velocity statistics and demonstrate that they are consistent with the dispersion parameters. 相似文献
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利用计算机模拟研究地铁火灾气温控制 总被引:3,自引:0,他引:3
分析了地铁火灾中烟气运动的物理模型和数学模型,并结合工程实例,对地铁隧道内发生火灾情况下,各种通风方案进行计算机模拟。并确定了最佳紧急通风方案。 相似文献
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烹调油烟气的成分及其分析方法 总被引:51,自引:2,他引:51
综述了烹调油烟气的历分及其分析方法,在烹调油烟气中检测到的成分至少3 300多种,具体尬发因熟钎条件不同而各异,主要有脂肪酸、烷烃、烯烃、醛、酮、醇、酯、芳香化合物和杂环化合物等。测定油烟气的方法主要有重量法,紫外分光光度法,薄层色谱法、高效液相色谱法、荧光分光光度法、握相色谱法、气相色谱-质谱联用法等。 相似文献
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《Atmospheric Environment. Part A. General Topics》1990,24(2):297-307
Plume dynamics and smoke injection into the atmosphere from large area fires ensuing a nuclear exchange are currently simulated by prescribed burns of smaller areas (radius < 1 km). The extent to which small area fire plumes accurately characterize those from larger urban fires (radius > 5 km) is not well established. A ‘large’ fire has a radius comparable to the stratification scale height of the atmosphere. Numerical simulations of smoke plumes and condensed-moisture clouds generated by small area fires are presented for three fire sizes and two ignition patterns for ‘average’ September Pacific Northwest atmospheric conditions. We find that the plume rise from small area fires is governed by the total heat release and entrainment, whereas that from large area fires is controlled primarily by the fire heating rate per unit area and the atmospheric stratification. 相似文献
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Feng Yingsheng 《环境科学学报(英文版)》1993,5(1):1-15
As the simple dispersion model tested is not sufficiently accurate to predict the SO2 concentration in complex terrain commonly encountered amongst high rise buildings in Hong Kong, and the lack of comprehensive local wind data at most sites prevents the use of more advanced dispersion model to assess the impact of major air pollutant sources, a receptor model approach is adopted for the apportionment of air pollution sources in Hong Kong. The preliminary results obtained are presented and discussed. 相似文献
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《Atmospheric Environment. Part A. General Topics》1993,27(1):73-82
We develop a simple analytical model to estimate the thickness of a smoke layer formed by a plume of a large area fire and to account for crosswinds. We take advantage of the dominant flow features in the upper part of the rising plume and in the smoke layer far from the plume to model the transition of a vertical flow to a horizontally spread thin smoke (or dust) layer. A one-dimensional approximation is used to model the buoyancy decay and plume overshoot. That solution is matched and combined with a solution based on the work required to establish our asymptotic horizontal smoke layer. The solution estimates the thickness of the spreading smoke layer in a quiescent atmosphere or in an ambient wind field. 相似文献
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高和文 《辽宁城乡环境科技》1997,17(4):61-62
文章介绍了TGXC-2除尘净化器在工业锅炉改造中的应用情况,安装该除尘器之后,达到了消烟除尘,除硫双轻重功能的理想效果,使烟气黑度,除尘效率,脱硫效率均达标。 相似文献
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为研究十六烷值改进剂和消烟剂对柴油机燃用乙醇柴油时颗粒排放特性的影响,在乙醇柴油中加入0.1%(以w计)、0.3%和0.5%的十六烷值改进剂或消烟剂,并在YZ4DB3柴油机上分别对这些燃料的排气烟度、颗粒比排放和粒径分布等进行研究. 结果表明:含添加剂的乙醇柴油颗粒物排放远低于0#柴油,降幅在50%以上;与0#柴油相比,添加0.3%十六烷值改进剂的乙醇柴油降低颗粒排放效果较显著,降幅高达64.2%,而添加0.1%消烟剂的乙醇柴油颗粒物排放降幅更高达84.0%,表明消烟剂的降颗粒效果更加显著. 柴油机燃用柴油时,排放颗粒的粒径呈双峰分布,峰值分别在0.56和0.18μm左右;但燃用含添加剂的乙醇柴油时,排放颗粒的粒径则呈单峰分布,其峰值均在>0.56~1.00μm粒径范围内. 柴油机燃用含添加剂的乙醇柴油后,0.18~0.32μm粒径范围内的排放颗粒显著减少,但在>0.32~1.00μm粒径范围内增加;同时,排放颗粒物中的积聚模态颗粒占排放颗粒总质量的比例降低,而粗粒子模态颗粒的所占比例相应增加. 排气烟度与积聚模态颗粒质量分布密切相关. 研究结果表明,柴油添加剂能够显著改善柴油机颗粒物排放特性,有利于改善大气质量. 相似文献
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蚊香燃烧产物中多环芳烃的分布规律及相关性研究 总被引:1,自引:0,他引:1
对蚊香燃烧后的烟气和灰烬样品进行采集,利用GC-MS方法分析其中16种优控多环芳烃(PAHs)的含量,并对烟气和灰烬中各PAHs组分及总量间的相关关系进行探讨.结果表明:蚊香烟气中16种PAHs均有检出,排放量较大的组分主要有萘、苊、二氢苊、菲和荧蒽,并以2~3环PAHs为主;灰烬中PAHs也以2~3环化合物为主,但排放总量仅为烟气中的4.7%~21.8%.通过与其他室内燃烧源PAHs排放量的对比发现,蚊香灰烬中总PAHs排放量低于卫生香源和木柴源,但比香烟源高一个数量级以上;烟气中总PAHs排放量低于燃煤源、木柴源和卫生香源,但明显高于烹调源.回归分析结果表明,烟气中总PAHs排放量与灰烬中的排放量表现出明显的线性关系(R2=0.9054). 相似文献