排序方式: 共有34条查询结果,搜索用时 15 毫秒
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通过采用LS-DYNA动力学有限元程序,模拟210 m钢筋混凝土烟囱的控制爆破拆除倒塌过程。采用数值模拟方法,不仅可以对控制爆破拆除工程中构筑物倾倒、破坏的重要影响因素进行分析,对有关理论研究结果的正确性和有效性进行验证,还能优化爆破拆除方案、预测实际爆破拆除效果,提高爆破拆除设计与施工的经济性、可靠性和安全性。 相似文献
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通过手工计算和ANSYS有限元软件计算两种方法对安徽新源热电有限公司烟囱与吸收塔合一结构进行结构计算。分析了结构在风载荷、地震载荷作用下的应力和变形,比较了手工计算和有限元电算结果,可为类似工程的计算提供理论参考。 相似文献
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Chung-Ming Liu 《Chemistry and Ecology》1996,12(1):147-161
In this paper, three sensitivity studies are designed to analyze the effect of the NMHC (Non-Methane HydroCarbon) composition, the aerosol back-scattering and the high chimney NOx emission to the photochemical prodution of ozone by using a one-dimensional photochemistry-diffusion model under a favourable meteorological condition. Measurements of the NMHC composition in Taipei indicated that the percentage of iso-butene, cis-2-butene, trans-2-butene and benzene in a unit volume was much higher than of those observed in other major cities. the high ratio of benzene was directly linked to its high percentage in gasoline. As to the unusually high amount of iso-butene, cis-2-butene and trans-2-butene, more researches are needed to identify their source. Concerns are raised as to how productive is NMHC composition is to the photochemical production of the surface ozone. A rough estimate shows that the total reactivity of the Taipei NMHC composition is about 1.21 × 10-9 cm3 s-1 which is 1.6 times that of the Los Angeles (LA) NMHC composition, while the simulated noon peak will be different by 28 ppbv, i.e. 18% more than that simulated with a LA composition.
Meanwhile, high aerosol loading is a serious problem in Taipei. the attenuation of the UV radiation by aerosols cannot be ignored. A numerical simulation shows that the noon ozone level will decrease from 178 to 141ppbv, i. e. about 21% reduction, with deterioration of the visual range from 85 to 5 km.
In the southern Taiwan, industry parks are mixed with the populated Kaohsiung city, hence the large emission of NOx from high chimneys cannot be ignored. in this study, NOx is assumed to be emitted in the layer between 235-460 m high with an emission rate of 0.05 or 0.145 ppbv/sec. the results show that the NOx emitted from the elevated stack lead to a considerable reduction of surface ozone. Such conclusion is obtained due to the fact that a one-dimensional model is used in this paper. Whereas, if a three-dimensional regional model was used, then a higher productivity of ozone downstream would be simulated. 相似文献
Meanwhile, high aerosol loading is a serious problem in Taipei. the attenuation of the UV radiation by aerosols cannot be ignored. A numerical simulation shows that the noon ozone level will decrease from 178 to 141ppbv, i. e. about 21% reduction, with deterioration of the visual range from 85 to 5 km.
In the southern Taiwan, industry parks are mixed with the populated Kaohsiung city, hence the large emission of NOx from high chimneys cannot be ignored. in this study, NOx is assumed to be emitted in the layer between 235-460 m high with an emission rate of 0.05 or 0.145 ppbv/sec. the results show that the NOx emitted from the elevated stack lead to a considerable reduction of surface ozone. Such conclusion is obtained due to the fact that a one-dimensional model is used in this paper. Whereas, if a three-dimensional regional model was used, then a higher productivity of ozone downstream would be simulated. 相似文献
6.
污染物高烟囱排放对改善污染物对地面的影响是很明显的,但是过高的烟囱不仅对企业投资是一种负担,而且还可能对周围环境产生景观上的不协调影响,因此环境影响评价中开展对烟囱高度合理性论证是非常必要的。以延安市某集中供热工程为实例,依照相关技术规范对烟囱高度的明确要求,并利用新版大气环境影响评价技术导则中推荐的SCREEN3模式,论证了该工程拟建设的120m高烟囱是合理可行的,同时得出了"高烟囱的设置可促成酸雨的形成"以及"过高的烟囱对环境质量的改善是并不明显的"这一结论。针对研究时存在的不足之处,最后提出了继续深入研究的方向。 相似文献
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安装太阳能烟囱后的建筑具有效果优良、节能环保的自然通风系统。室内通风口高度是太阳能烟囱建筑性能的关键参数之一。提出通过改变太阳能烟囱建筑室内通风口高度位置,使太阳能烟囱既可用于建筑的日常自然通风,也能实现室内火灾场景下的自然排烟。利用缩比例实验台研究了不同室内通风口高度对太阳能烟囱建筑自然通风与自然排烟效果的影响,发现自然通风和自然排烟效果随通风口高度增加呈现先增大后减小的趋势,且最佳室内通风口高度位于窗户上檐位置附近。研究结果对太阳能烟囱建筑的建筑结构关键参数设计具有指导意义。 相似文献
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不同排放高度的污染源对城市大气污染的贡献分析 总被引:3,自引:0,他引:3
将沈阳市的大气污染排放源按其排放高度分成3类:(1)烟囱高度<35m;(2)35m≤烟囱高度≤55m;(3)烟囱高度>55m。并分别计算了不同类别高度的污染源对沈阳市各监测点的浓度贡献,通过计算得知,沈阳市35m以下的污染源SO2的排放量占全市总排放量的16.5%,而造成的地面浓度却占45.8%,其贡献率接近一半;烟囱高度在35~55m之间的污染源排放量占全市总排放量的14.7%,造成的地面浓度占33.7%,;55m以上的污染源SO2的排放量占全市总排放量的68.8%,而造成的地面浓度只占20.5%。 相似文献
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Rayan Rabehi Abla Chaker Zeroual Aouachria Ming Tingzhen 《International Journal of Green Energy》2017,14(12):971-982
The solar chimney power plant (SCPP) is a power generator which uses solar radiation to increase the internal energy of the air circulating in the system, thereby transforming the useful gain of the solar collector into kinetic energy. The produced kinetic energy then can be converted into electrical energy by means of an appropriate turbine. In this paper, four locations in Algeria
(Constantine, Ouargla, Adrar, and Tamanrasset) were considered as case studies to describe the SCPP mechanism in detail. Numerical simulation of an SCPP which has the same geometrical dimensions was performed to estimate the power output of SCPP in these regions. Using the CFD software FLUENT we simulated a two-dimensional axisymmetric model of a SCPP with the standard k-ε turbulence model. The simulation results show that the highest power output produced monthly average value 68–73 KW over the year and the highest hourly power produced in June is around 109–113 KW. 相似文献
10.
Chung-Ming Liu 《Chemistry and Ecology》2013,29(1-2):147-161
Abstract In this paper, three sensitivity studies are designed to analyze the effect of the NMHC (Non-Methane HydroCarbon) composition, the aerosol back-scattering and the high chimney NO x emission to the photochemical prodution of ozone by using a one-dimensional photochemistry-diffusion model under a favourable meteorological condition. Measurements of the NMHC composition in Taipei indicated that the percentage of iso-butene, cis-2-butene, trans-2-butene and benzene in a unit volume was much higher than of those observed in other major cities. the high ratio of benzene was directly linked to its high percentage in gasoline. As to the unusually high amount of iso-butene, cis-2-butene and trans-2-butene, more researches are needed to identify their source. Concerns are raised as to how productive is NMHC composition is to the photochemical production of the surface ozone. A rough estimate shows that the total reactivity of the Taipei NMHC composition is about 1.21 × 10?9 cm3 s?1 which is 1.6 times that of the Los Angeles (LA) NMHC composition, while the simulated noon peak will be different by 28 ppbv, i.e. 18% more than that simulated with a LA composition. Meanwhile, high aerosol loading is a serious problem in Taipei. the attenuation of the UV radiation by aerosols cannot be ignored. A numerical simulation shows that the noon ozone level will decrease from 178 to 141ppbv, i. e. about 21% reduction, with deterioration of the visual range from 85 to 5 km. In the southern Taiwan, industry parks are mixed with the populated Kaohsiung city, hence the large emission of NO x from high chimneys cannot be ignored. in this study, NO x is assumed to be emitted in the layer between 235–460 m high with an emission rate of 0.05 or 0.145 ppbv/sec. the results show that the NO x emitted from the elevated stack lead to a considerable reduction of surface ozone. Such conclusion is obtained due to the fact that a one-dimensional model is used in this paper. Whereas, if a three-dimensional regional model was used, then a higher productivity of ozone downstream would be simulated. 相似文献