激光散射法测量烟幕质量浓度的试验研究

为实现实时测量烟幕粒子数浓度、质量浓度和烟幕粒子的粒径分布,开发一种烟幕质量浓度测量装置,该装置采用激光前向散射原理和消光法测量原理相结合的方法。通过测试数据,可以计算出某一时刻的烟幕粒子数浓度和质量浓度的平均值。结果表明:烟幕质量浓度测量装置运行正常,粒径及粒径分布测量值准确。     

浅析电子烟雾测量技术

现如今,电子烟逐渐成为了传统卷烟的替代品,市场销量大增,许多大型烟草公司已从战略高度积极研发、推广电子烟产品。电子烟烟雾量为评价电子烟品质的重要指标之一,现今国内外的电子烟气溶胶测量的检测手段多数是非在线、非定量的测量,电子烟烟雾量的检测方法并不完善,因此迫切需要一种在线、定量的更有效的检测方法,实现电子烟烟雾量的在线、定量测量的目标。所以,需要从多个角度入手提高电子烟品质,相关电子烟制造厂商需要采用有效的电子烟雾测量技术。该文就此对电子烟雾测量技术相关内容进行分析,基于气溶胶光学特性、高效液相色谱法和GC-MS测定测定烟雾质量浓度,对电子烟雾进行分析。     

地面气溶胶集成观测系统

介绍一种地面气溶胶集成观测系统的设计思路和集成方法,采用浊度仪、吸收光度计、粒子计数器、粒径谱仪、碳黑仪等仪器观测气溶胶的散射和吸收特性、黑碳浓度、粒径分布和粒子数浓度等。结果表明,测量吸收特性和粒子数浓度的仪器位于测量散射特性的仪器之后,仪器之间可以互相对比验证;将测量气溶胶吸收特性的仪器和黑碳仪"并联",可以观测到更多气溶胶特性信息;测量气溶胶粒径分布及粒子数浓度的仪器可以结合使用,也可以单独分开或"并联"综合观测;仪器综合集成观测的前提是保证仪器流量分配正确,切割头流量达到要求的范围,保证切割效率。     

河北地区秋季大气气溶胶物理特征分析

利用2005年10月20日在河北省石家庄和邯郸地区进行的一次飞机探测资料,初步分析了石家庄和邯郸上空的气溶胶粒子数浓度、粒径、粒子谱垂直分布特征,对石家庄与邯郸之间的水平飞行气溶胶粒子数浓度资料进行分析,并对石家庄、邯郸的气溶胶粒子谱进行函数拟合。结果表明:各高度层气溶胶粒子数浓度基本上都是石家庄高于邯郸,各高度层粒子平均直径基本上都是石家庄低于邯郸。两地气溶胶粒子数浓度、粒子平均直径随高度的分布有不同特点。石家庄、邯郸气溶胶粒子谱谱型,低层相似,基本都是单调下降,高层粒子谱谱型为多峰型。3100m高度层粒子数浓度在水平方向上分布不均匀,城市附近上空气溶胶粒子数浓度相对较大,郊县气溶胶粒子数浓度相对较小。随着高度增加,粒子数浓度减小,水平方向的绝对变化越来越小。利用幂函数N(D)=AD-B可以对不同高度气溶胶粒子谱进行较好的拟合。     

碳纳米材料空气动力学性能的实验研究

测试八种碳纳米材料喷洒在烟幕箱内形成烟幕的质量浓度及对1.06μm激光的透过率,根据不同时间的采样浓度计算得到烟幕的沉降速度.结果表明:碳纳米材料烟幕具有良好的悬浮性能;直径在40nm以上,长度不大于15μm的纳米碳纤维材料形成的烟幕具有足够的质量浓度和良好的漂浮特性,比较适合作为电磁波干扰材料;纳米SiO2可有效改善发烟剂的流动性和分散性、延长烟幕的留空时间,并能显著地降低烟幕粒子的沉降速度.     

粉体气溶胶旋流生成效率的试验研究

针对一种3级旋流-粉体气溶胶发生装置,测试分析旋流生成气溶胶的粒谱分布特征,由此定义气溶胶旋流生成效率;研究气流压力、脉冲时间、粉体装填量、旋流喷嘴结构等参数对生成效率的影响。结果表明,旋流装置对粒径为1~10μm的超细粉体能达到很高的气动分散效率;在较小的气流压力下,旋流装置仍能获得很高的气溶胶生成效率;适当减小粉体装填量,可改善气溶胶的生成效果;进气角度、出口锥角分别为15、45°时,气溶胶生成效率最高。     

深圳市环境空气中黑碳气溶胶的污染特征研究

为了解深圳市环境空气中黑碳气溶胶(BC)的污染状况及变化规律,2009年利用黑碳仪(aethalometer)对黑碳气溶胶组分进行了在线观测及来源分析研究.结果表明:大气环境中黑碳气溶胶质量浓度为5.72μg·m-3,占PM25的14.8％,且黑碳气溶胶浓度呈现冬高夏低、占PM25比例呈现夏高秋低的变化趋势.各季节BC浓度均具有显著的日变化,风向分析表明:静风时BC浓度较高,说明BC主要来自本地污染源;而区域污染传输发生时,东北方向的传输更易影响深圳市BC污染水平.     

硝化棉在线连续计量技术研究

根据硝化棉浆料特性,利用微波浓度仪和电磁流量计分别对输送过程的硝化棉(NC)浆料质量分数和流量进行测量。文中详细分析了微波浓度仪和电磁流量计工作原理。设计了硝化棉干量连续测量系统(PLC),PLC将来自微波浓度仪的质量分数信号和电磁流量计的流量信号进行处理,得到输送管道中NC浆料瞬时干量和一定时间内的累计干量。试验结果表明:硝化棉干量在线连续测量误差小于1.2%,能满足火药制造工艺连续化、自动化的需要。     

气溶胶在岩体裂隙中迁移特性的实验研究

为得到实际岩体裂隙中气溶胶的穿透行为特性,为山体中存储间的选址及洞室工程防护措施的制定提供精确的数据支持,利用电子低压碰撞器对气溶胶在岩体裂隙中的穿透率进行实验测量,得到气流速度、粒径大小、裂隙长度、裂隙高度等参数对穿透率的影响。结果表明,在较低的流速下,小粒径粒子的穿透率随流速的增大稍微增大,大粒径粒子趋势不明显;随着气溶胶粒径的增大,穿透率先增大后减小,峰值在0.3～1.0μm之间;随着裂隙长度的增加,穿透率呈指数减小,且不同长度裂隙、不同粒径气溶胶粒径的穿透率减小趋势基本一致;裂隙高度的增加使气溶胶的穿透率显著增大,高为1.0 mm的裂隙中,气溶胶的穿透率更大,更接近理论结果;在常温常压下,高为0.1 mm的裂隙中,流速为5.6 m/s时,粒径为0.3μm的气溶胶在0.1 mm宽岩体裂隙中的迁移距离非常有限。粒子除了受重力沉积和扩散沉积作用,还受到碰撞效应等作用。     

洞室气溶胶穿透率测量实验研究

为评价某洞室对气溶胶粒子的封堵特性,利用电子低压碰撞器(ELPI)对洞室气溶胶穿透率进行实验测量,得到气溶胶渗透进入洞室的穿透率,初步建立评价洞室气溶胶穿透率的方法。结果表明:该洞室气溶胶的穿透率为0~0.32,对应粒径为0.08~3μm,显著低于一般居所的气溶胶穿透率。通过两次实验测量对比发现,洞室的整体穿透率由少数较大裂隙决定,有效封堵大裂隙可以显著减小气溶胶的穿透率。     

基于ELPI测量系统的撞击器分离特性曲线刻度

为对设计完成后的应用于气溶胶分级采样测量中的撞击器进行实验刻度,在分析原有单分散粒子刻度法的基础上,针对其存在的问题,建立基于电子低压碰撞器(ELPI)测量系统的混合源刻度方法;利用该方法对某撞击器的分离曲线进行刻度,并使用单分散粒子刻度法对其进行对照验证。结果表明,混合源刻度法的分离特性曲线拟合后判定系数R2为0.928 35,比单分散粒子刻度法的拟合曲线更好。     

一种新型粉体分散装置的实验研究

为了获得高质量的粉体气溶胶,开发了一种依据浮动压差原理设计的新型粉体分散装置,同时利用该装置进行不同粒径滑石粉的分散实验,分析气溶胶生成质量,考察气体压力、气流量及粉体剩余量等因素时粉体输送量的影响。该分散装置采用锥体流化板结构使物料与空气充分混合,在空气中形成有效的粉体气溶胶,并通过流量控制装置控制气体压力和流量,从而控制粉体的输送速度和输送量。结果表明,该装置能够生成粒径在2μm左右的固体气溶胶,可以通过控制高压空气流量控制粉体输送量。     

Identification of organic acids in secondary organic aerosol and the corresponding gas phase from chamber experiments

Organic acids in the gas and aerosol phase from photooxidation of 1,3,5-trimethylbenzene in the presence of 300 ppb propene and 300 ppb NOx in smog chamber experiments were determined using a wet effluent diffusion denuder/aerosol collector coupled to ion chromatography (IC) with conductivity detection. Behind the IC, the samples were collected using a fraction collector, for identification of unresolved/unidentified organic acids with IC-mass spectrometry (MS). In total, 20 organic acids were found with MS of which 10 were identified. The organic acids identified offline by IC-MS were then further quantified based on the online IC data. The identification was additionally confirmed with gas chromatography-mass spectrometry. At the maximum aerosol concentration, organic acids comprised 20-45% of the total aerosol mass. The method has a detection limit of 10-100 ng/m3 for the identified carboxylic acids.     

Deposition of aerosol particles in a model vitreous chamber

The purpose of this study was to assess quantitatively the aerosol deposition in a model eye chamber to identify the mechanism(s) of deposition and delivery efficiency for application in retinal disease treated with vitrectomy. Dry aerosol particles were produced with mixtures of fluorescein and a variable concentration of cesium chloride, which ranged in aerodynamic size from 0.6 to 1.3 μm. The aerosol was injected through a small inlet tube into Teflon chambers that had a vented, spherical cavity (diameter ?"). Two filling times of 60 s and 90 s were used. Although significant loss occurred in the syringe, the mass deposited within the chambers increased with aerosol concentration and ranged from 0.5 to nearly 15 μg. Between 60 and 90% of the mass was deposited on the lower surface of the chamber. The mechanism of deposition was consistent with diffusion through a boundary layer during filling followed by sedimentation of the remaining suspended aerosol particles. Based on these results, an aerosol with a median particle size of 1.3 μm was shown to provide a therapeutically effective dose of 5-fluorouracil. The approach is general and can be applied to the aerosol delivery of other drugs to the vitreous chamber.     

一种气溶胶光度计质量浓度的校准方法

介绍了气溶胶光度计的内部机构和工作原理,提出了一种基于滤膜采样法的气溶胶光度计质量浓度校准装置和校准方法;通过实验验证了气溶胶发雾混匀装置发雾浓度稳定性小于5%,气溶胶光度计质量浓度示值误差小于±10%。解决了气溶胶光度计质量浓度的量值溯源,能够有效提高该设备测量准确度。     

气雾剂灌装在线摇摆技术的实现

目的提出并实现一种气雾剂灌装在线摇摆装置。方法对现有灌装生产线进行改造,设计摇摆装置的机械结构,加装摇摆工位,并且对该摇摆装置进行PLC控制,增加气雾剂灌装线的在线摇摆功能。着重分析在线摇摆装置的结构,同时对其工作原理进行分析,然后给出控制系统的实现方案。结果该气雾剂灌装在线摇摆装置能实现不同数量的产品、不同幅度和频率的摇摆,其工作可靠,摇摆充分均匀稳定。结论为气雾剂灌装在线摇摆的实现提供一种可行性方案,同时促进了我国气雾剂灌装生产线自动化升级改造。     

基于压缩式循环的CO2水合物蓄冷系统SDS强化实验研究

本文基于压缩式循环原理,采用水冷式直接接触式蓄冷系统,研究了不同充注压力(3.5、3.6、3.7、3.8、3.9、4.0 MPa)和不同质量浓度(0.3、0.5、0.7、0.9 g/L)的十二烷基硫酸钠(SDS)溶液中,CO2水合物的生成特性和蓄冷特性。根据实验数据对蓄冷量、蓄冷速率和CO2水合物生成质量进行计算,结果表明:与未添加SDS的溶液相比,含有不同质量浓度的SDS溶液中,系统的预冷时间和蓄冷时间均缩短,水合物生成质量、总蓄冷量及平均蓄冷速率均有所提升,且随着充注压力的不断提高,系统的蓄冷性能也不断加强。当充注压力为4.0 MPa,SDS溶液质量浓度为0.5 g/L时,预冷时间(5.58 min)和蓄冷时间(10.92 min)达到最短。此时,系统的总蓄冷量(4021.2 kJ)、潜热蓄冷量(2476.8 kJ)、CO2水合物生成质量(4.95 kg)及平均蓄冷速率(6.14 kW)均达到最大值,即系统蓄冷能力达到最强,说明SDS对于本系统的CO2水合物蓄冷性能具有明显的强化效果。     

Effect of particle spatial distribution on particle deposition in ventilation rooms

We used simulations and experimental tests to investigate indoor particle deposition during four commonly used ventilation modes, including ceiling supply, side-up supply, side-down supply and bottom supply. We used a condensation monodisperse aerosol generator to generate fine diethylhexyl sebacate (DEHS) particles of different sizes along with two optical particle counters that measured particle concentration at the exhaust opening and inside a three-dimensional ventilated test room. We then simulated particle deposition using the same ventilation modes with computational fluid dynamics (CFD) method. Our simulated results indicate that mean deposition velocity/rate for particles 0.5–10 μm (aerodynamic diameter) is not affected by different ventilation modes. However, both our experimental and simulated results indicate that the deposition loss factor, a parameter defined based on mass balance principle to reflect the influence of particle distribution on deposited particle quantity, differ significantly by ventilation mode. This indicates that ventilation plays an important role in determining particle deposition due to the apparent differences in the spatial distribution of particles. The particle loss factor during ventilation modes characterized by upward air flow in the room is smaller than that of mixing ventilation; however this trend was strongly influenced by the relative location of the inlets, outlets and aerosol source.     

Performance evaluation of a new micro gas cyclone using simulation and experimental studies to capture indoor fine particles

The aim of this study was evaluating a micro gas cyclone performance with a body diameter of 10?mm to collect indoor fine particles. The design of a cyclone requires minimizing the pressure drop and maximizing the separation efficiency. Overall and grade efficiencies, pressure drops, and cut sizes have been investigated through a theoretical model, simulation, and experimental studies. The experimental part was conducted using an Electrical Low-Pressure Impactor (ELPI) device to measure particle concentration for flow rates of 10–13.3 (l/min). In order to study the pressure drop and velocity behavior for different flow rates, COMSOL software was utilized. The obtained results from experimental work have met the theoretical and simulation outcomes adequately. It has been confirmed by all the obtained results that by increasing the flow rate and subsequently inlet velocity, the particle collection efficiency and pressure drop increase while the cut size decreases.