狭缝结构对船用排气引射装置气膜冷却性能影响的模拟研究

船用燃气轮机的排气温度很高,为了降低排气管道和排气烟羽的红外辐射,在排气喷管上方安装排气引射装置,利用引射原理卷吸环境中的冷空气,降低排气温度,同时在壁面上形成冷却气膜,防止壁面温度升高。排气引射装置的扩压管为多级圆环结构组成,文中利用数值计算的方法模拟了扩压管圆环间狭缝结构对壁面温度的影响,得到了壁面上的温度分布,确定了冷却气膜的长度,为扩压管的设计提供了参考。     

城市道路机动车尾气污染物扩散模型研究概况

介绍了国外几个主要城市道路机动车尾气污染物扩散模型,以及模型的分类、特点和发展过程。同时,简要介绍了国内学者利用主要扩散模型对于城市道路机动车污染物的研究。     

LNAPL在砂质含水层中动态迁移的电阻率法监测试验研究

在海滨潮间带采集细砂,通过室内柴油泄漏模拟试验,利用自制电阻率监测系统对轻非水相液体在砂土-地下水系统垂向渗透过程进行电阻率变化动态监测;通过配制不同含油率砂土测定其静态电阻率变化规律,探讨电阻率变化的影响因素;最后取样分析测定污染含水介质稳定后含水率及含油率,对监测结果有效性进行了验证;并利用显微成像法对污染砂土进行了微观形态分析.结果表明,柴油污染砂土微观形态上胶结现象明显;柴油渗透海滨砂土过程电阻率大小同含水饱和度,比电阻率和含油饱和度之间存在良好的相关性,均可用Archie公式拟合,n值分别为2.36和0.15;通过电阻率测定可以有效估算柴油透镜体厚度;电阻率随深度的变化可以反映含油率和含水率的垂向分布.本研究为轻质油品储罐或者海上油品输运过程泄露造成的海滨砂土地下污染扩散过程监测及机制研究提供了一种有效的方法,也可为其他典型石油泄漏污染场地的电阻率法探测或监测提供参考.     

Impacts of converting from leaded to unleaded gasoline on ambient lead concentrations in Jakarta metropolitan area

Total suspended particulate mater （TSP） concentrations were monitored for one year from July 2000 and for one year from April 2003 in Jakarta City. Thirteen elemental TSP components, aluminum （Al）, sodium （Na）, iron （Fe）, lead （Pb）, potassium （K）, zinc （Zn）, titanium （Ti）, manganese （Mn）, bromine （Br）, copper （Cu）, chromium （Cr）, nickel （Ni）, and vanadium （V） were analyzed by a sequential X-ray fluorescence spectrometer. Al, Na, Fe, K, and Pb were major components at most of the sampling locations in 2000. However, only Pb in 2003 dramatically decreased to one tenth. The phase-out of leaded gasoline began on July 1, 2001 in Jakarta City and lead content in gasoline decreased to one tenth, too. The decrease in Pb concentration was a result of the phase-out of leaded gasoline, as lead emissions mainly are exhaust gas from vehicles.     

Effects of nitrate concentration in interstitial water on the bioremediation of simulated oil-polluted shorelines

Nutrient addition has been proved to be an effective strategy to enhance oil biodegradation in marine shorelines.To determine the optimal range of nutrient concentrations in the bioremediation of oil-polluted beaches,nitrate was added to the simulated shoreline models in the initial concentration of 1,5 and 10 mg/L.Whenever the NO3-N concentration declined to 70% of its original value, additional nutrients were supplemented to maintain a certain range.Results showed adding nutrients increased the oil biodegradation level,the counts of petroleum degrading bacteria(PDB)and heterotrophic bacteria (HB),and the promoted efficiency varied depending on the concentration of nitrate.Oil degradation level in 5 mg/L(NO_3-N)group reached as much as 84.3% accompanied with the consistently highest counts of PDB;while in 1 mg/L group oil removal efficiency was only 35.2%,and the numbers of PDB and HB were relatively low compared to the other groups supplemented with nutrients.Although counts of HB in the 10 mg/L group were remarkable,lower counts of PDB resulted in poorer oil removal efficiency (70.5%) compared to 5 mg/L group.Furthermore,it would need more NO_3-N(0.371 mg)to degrade 1 mg diesel oil in the 10 mg/L group than in the 5 mg/L group(0.197 mg).In conclusion, Nitrate concentration in 5 mg/L is superior to 1 and 10 mg/L in the enhancement of diesel oil biodegradation in simulated shorelines.     

含信号控制人行横道的街道峡谷污染物扩散三维数值模拟

耦合微观交通仿真和机动车尾气排放模型,分别对含信号控制人行横道和不含信号控制人行横道的街道峡谷污染物排放进行计算,并以此为排放源,采用k-ε两方程模型与组分输运方程对风向与街道垂直时的污染扩散情况进行了三维数值模拟.结果表明,k-ε两方程模型与组分输运方程可以较好地模拟风向与街道垂直时三维街道峡谷内的污染物扩散情况.峡...     

水泥窑协同处置POPs污染土壤对环境的影响研究

 分析了水泥窑协同处置POPs污染土壤对烟气中污染物排放和熟料品质的影响,结果表明,SO2、NOx、HCl、Hg、As、Ni、Pb、粉尘、二 的排放量均低于工业大气污染物排放规定限制,与空白试验相比,水泥窑协同处置污染土壤过程中烟气中特征污染物排放量没有显著增加.水泥熟料化学成分满足相关规定,熟料产品质量达到相关标准,因此利用水泥窑协同处置POPs污染土壤是一种环境友好处理方式.     

Cu-K型低温碳烟氧化催化剂的合成及表征

柴油机排放中碳烟的低温氧化是近年来研究的热点.通过原位合成法制备Cu2K/Al2O3和CuK／Al2O3两种碳烟氧化催化剂,并采用低温氮吸附/脱附实验、X射线衍射、X射线光电子能谱、程序升温氧化对其结构进行系统表征,并用U碳模拟柴油机碳烟,研究其催化活性,评测其对柴油机排气中碳烟颗粒的净化效果.研究表明,Cu2K/Al...     

一次环境污染司法鉴定的测试与分析

受人民法院的委托,环境监测部门对一起汽车尾气致人死亡案件的现场进行大气污染物和空气质量的模拟测试。测试表明,在密闭的车库内,汽车外和汽车内CO浓度都会迅速增加,达到致人死亡的浓度,O2浓度迅速减少,最终使汽车发动机熄火。测试为司法部门提供案件审理现场空气质量数据,也提醒人们不要在密闭的车库内开启汽车空调取暖或纳凉休息。     

Experimental study on filtration and continuous regeneration of a particulate filter system for heavy-duty diesel engines

This study investigated the filtration and continuous regeneration of a particulate filter system on an engine test bench, consisting of a diesel oxidation catalyst（DOC） and a catalyzed diesel particulate filter（CDPF）. Both the DOC and the CDPF led to a high conversion of NO to NO2 for continuous regeneration. The filtration efficiency on solid particle number（SPN） was close to100%. The post-CDPF particles were mainly in accumulation mode. The downstream SPN was sensitively influenced by the variation of the soot loading. This phenomenon provides a method for determining the balance point temperature by measuring the trend of SPN concentration.