暴雨径流中固液旋流分离试点研究

为了改善镇江市水质环境，在点源污染得到控制的情况下减少面源污染，在排水管网中安置预先设计好的下水道水力旋流器进行现场试验，在降雨期对进出口水质采样，检测总氮、总磷、SS、浊度、pH、COD这五个指标，分析水力旋流器的处理效率，为水力旋流器运用于镇江市整个管网中做技术支持。     

固-液分离水力旋流器内速度场数值模拟研究

依据计算流体动力学（CFD）的计算方法,利用FLUENT软件对水力旋流器内清水流场进行了三维数值模拟研究,并将模拟所得的流场与实测结果作对比,证明该软件模拟效果良好,从而为进一步研究旋流器固-液分离现象提供了一定的指导。     

相关参数对水力旋流器效率的影响

水力旋流器是一种常见的分离分级设备,该文简单叙述了其相关的工艺计算,并概述了结构参数和工艺参数对其自身分离分级效率的影响。     

大直径混凝土管片气泡的防治研究

混凝土管片是盾构隧道的主要结构构件,也是隧道防水、防火和耐久等综合性能的保证,因此,对管片整体性能有着极高要求。但大直径混凝土管片在生产中易出现较多气泡,从而易形成渗漏通道,影响管片的耐久性。本文从混凝土原材料、配合比设计、模具、脱模剂、振捣工艺等方面入手,试验摸索出减少管片气泡的一套方法,在生产实践中收到了较好的效果。     

气液分离的消防员紧急供气装置研究

针对消防员被困需要紧急供气呼吸的场景,该文通过研究设计气液分离的消防员紧急供气装置连接在消防水带、室内消防给水管道接口等,一端接供气设备,另一端由消防员将呼吸面罩接驳于紧急供气装置,当管路内液体处于非满管流时,即可用于紧急供气呼吸;对于水带内是泡沫时,还可以提取其中的空气供消防员应急呼吸,节约了排泡沫时间,对于保障消防救援人员的生命安全有着重要意义。     

取土器直径对取样扰动的影响分析

不同直径的取土器对土样扰动的影响程度不同 ,恰当选择取土器的直径 ,对取土质量是非常重要的。直径过小 ,不能保证取土质量 ;直径过大 ,增加钻探费用。本文强调有条件和经济允许的话 ,应该优先考虑大直径的取土器。     

硅灰对混凝土气泡特征参数的影响

通过试验分析了硅灰掺量与混凝土含气量、气泡间距系数和气泡平均直径之间的关系。结果表明,随着硅灰掺量的增加,新拌及硬化混凝土的含气量均有不同程度降低,混凝土气泡间距系数和气泡平均直径也呈减小趋势。掺加硅灰可以细化混凝土浆体内部孔隙,一定程度上优化了混凝土的气泡结构,有利于提升混凝土的性能,硅灰掺量不宜超过9%。     

矿物掺合料对混凝土气泡特征参数的影响

研究了粉煤灰、矿粉对引气混凝土气泡特征参数的影响.结果表明:无论是单掺还是双掺粉煤灰和矿粉,新拌及硬化引气混凝土的含气量均有不同程度的降低;单掺粉煤灰引气混凝土的气泡间距系数和气泡平均直径降低,有利于提高混凝土抗冻性;矿粉对引气混凝土的气泡特征影响较大,且气泡特征参数的影响无明显的规律性;矿物掺合料一定程度上能改善引气混凝土的气泡结构,有利于提高抗冻性能,但掺量不宜超过30％.     

辊轴直径对混凝土抗折强度的影响分析

混凝土的抗折强度是用来提供设计参数和检查混凝土质量的指标之一,对于混凝土路面来讲尤为重要。在新的抗折试验装置中,将4个加荷点的钢球和活动船形垫块改为4个辊轴,对不同辊轴直径对抗折强度的影响进行了比较,从而得出一个合理的比值,对混凝土抗折试验有较大的指导意义。     

非球形颗粒旋风分离特性试验研究

为了考察非球形颗粒的分离特征,采用对比试验的方法,以非球形的硅微粉和球形的粉煤灰为介质,测量其分离特性。结果表明:对于这两种颗粒,分离效率均随入口气速增加先升高后下降,压降随入口气速的增加持续上升,且分离效率和压降均随温度升高而降低;尽管硅微粉的密度更大、颗粒偏粗,但在相同条件下,其分离效率却比更轻、更细的粉煤灰的低,且压降也更低,原因在于硅微粉所形成的灰层在器壁上"滑动"困难,器壁摩擦损失较大,会削弱旋流强度,导致离心分离能力下降,加上非球形颗粒在离心沉降过程中的绕流阻力更大,故分离效率变得更低。对于压降,虽然器壁摩擦损失增大会导致压降升高,但旋流强度的减弱又使旋转动能耗散减少,压降降低,综合结果是分离硅微粉时压降比分离粉煤灰时的低。     

Similarities of pressure induced by separation bubble in grid-generated turbulent flow

Some existing wind-tunnel data on mean pressure and fluctuation pressure distributions, induced by a separation bubble near the leading edge of a blunt plate, in the presence of grid-generated freestream turbulence, are systematically analyzed in this paper. The mean pressure distributions, when expressed in reduced coordinates, are self-similar and may be approximated by the pressure variation induced by an inviscid rotational vortex hovering above a flat surface in uniform smooth flow. These coordinates are expressed in terms of characteristic parameters of the mean flow field and each parameter has been correlated with the longitudinal component of the turbulence intensity and scale non-dimensioned by the plate thickness. In analyzing the pressure fluctuation, a similar approach is used. The results from the rotational vortex are consistently useful when considering the leading portion of the bubble characterized by the location of maximum fluctuation. The remaining portion may be represented by an exponential function characterized by the turbulence intensity only. The outcome of this study may be used as a prediction method whose validity has been checked with experimental data.     

起泡剂溶液的表面张力对气泡尺寸的影响

具有起泡能力的表面活性剂的添加是气泡尺寸调控的一个重要手段。以甲基异丁基甲醇(MIBC)、仲辛醇、甲氧基聚丙烯乙二醇(DF250)、辛基酚聚氧乙烯醚(OP-10)4种具有起泡能力的表面活性剂为试验对象,测试了4种起泡剂溶液中表面张力随起泡剂浓度的变化规律及其对气泡尺寸的影响;并通过气泡直径的测量,得到4种起泡剂的临界兼并浓度。结果表明:随着起泡剂浓度的增大,4种起泡溶液的表面张力均逐渐减小并最终趋于不变;起泡剂的表面活性越强,其临界兼并浓度值(CCC)越小,三种醇类起泡剂的CCC值分别为MIBC 22.6mg/L,仲辛醇18.2mg/L,DF250 11.6mg/L,而表面活性最强的醚类起泡剂OP-10的CCC值仅为5.3mg/L。     

苏北盆地古近系页岩油储层有效裂缝识别

为了查明苏北盆地古近系阜宁组四段(E_1f~4)裂缝型页岩油资源的富集规律,对钻孔岩芯所含裂缝进行了精细地观察与描述,对区内E_1f~4页岩基质和裂缝充填方解石进行了碳氧同位素测试、结合区域埋藏史、生烃史,总结了区内油页岩储层裂缝成因类型与特征,划分了裂缝形成期次并识别了有效裂缝。结果表明:研究区E_1f~4页岩裂缝可分为4种成因类型:平移式剪裂缝、正向剪切缝、逆向剪切缝和顺层缝;构造裂缝可分为5期次,其中,第Ⅰ期为平移式剪切缝,未见原油显示,形成于吴堡运动;第Ⅱ期为正向剪切缝,未见原油显示,形成于真武运动早期;第Ⅲ期为顺层缝,原油显示丰富,形成于三垛运动中期;第Ⅳ期为正向剪切缝,原油显示丰富,形成于三垛运动晚期;第Ⅴ期为逆向剪切缝,属压性缝,形成于三垛运动末期。第Ⅲ期和第Ⅳ期裂缝原油显示丰富,气测异常明显,为有效裂缝。     

添加剂对制备纳米直径硬硅钙石纤维的影响

采用工业石灰和石英粉,选用氯化钙、硝酸锶、氧氯化锆为添加剂,研究添加剂对合成纳米直径硬硅钙石纤维的影响,结果表明,几种添加剂均对生成硬硅钙石纤维有一定的帮助,加入适量的氧氯化锆添加剂,可以制备出纳米直径的硬硅钙石纤维,氧氯化锆的添加量为Zr4 /(Ca2 Si4 )=0.02(摩尔比)时,可获得结晶良好、直径为70～100 nm的硬硅钙石纤维。     

气液流量对低压双流体细水雾雾场特性的影响

由于对民机货舱中不同气液流量的低压双流体细水雾研究较少,且对单个喷头雾通量和雾动量的定量、定性分析不够完善,还需设计开展实验进行更深入的研究。参考美国联邦航空管理局（简称“FAA”）制定的相关标准,设计并搭建飞机货舱低压双流体细水雾实验平台,主要包括FAA全尺寸飞机货舱、低压双流体细水雾系统。采用的喷头与常规的喷头有所不同,喷出的细水雾是一个圆形平面,具有优良的弥散性和滞空性。实验中采用马尔文粒径分析仪结合Spraytec软件测量不同气液流量下的细水雾雾滴粒径,发现当气体流量从250 L/min增加至350 L/min、液体流量保持0.5 L/min不变时,细水雾雾滴粒径从130 μm降低至95 μm;当液体流量分别为0.75 L/min和1.0 L/min时,粒径大小分别从161 μm降至110 μm,从201 μm降至142 μm。根据美国防火协会的标准,采用量杯收集法测量得到不同气液流量下的雾通量,发现单独增加气体流量或液体流量,其雾通量都会增加。当气体流量为350 L/min、液体流量为1.0 L/min时,雾通量达到最大值,为0.255 L/（min·m2）。利用粒子图像测速仪的高速摄像机拍摄喷雾照片,测量雾滴速度,结果显示,在3种不同的液体流量工况下,随着气体流量从250 L/min增加至350 L/min,对应的雾滴速度均近似以0.04的增长率上升,最小值为8.5 m/s,最大值为16.0 m/s。在假设细水雾雾滴形状为球状时,雾动量关系式由雾滴质量与速度的乘积得到。选取雾滴速度最大值代入公式,得到单个雾滴在不同气液流量下的雾动量变化曲线,发现当气体流量为250 L/min、液体流量为1.0 L/min时,单个雾滴动量达到最大值,为3.6×10-8 kg·m/s。通过实验研究不同气液流量对低压双流体细水雾雾场特性的影响,得出以下结论：当液体流量不变,气体流量从250 L/min以25 L/min的变化率增加至350 L/min时,雾滴粒径和雾动量逐渐减小,而雾滴速度和雾通量逐渐增加;当气体流量不变,液体流量从0.5 L/min以0.25 L/min的变化率增加至1.0 L/min时,雾滴粒径、雾动量和雾通量均逐渐增大,而雾滴速度逐渐减小。对于单个雾滴,雾动量取决于雾滴粒径的大小;而对于喷头喷出的所有雾滴,雾滴速度决定了整体雾动量的大小。今后课题将进行细水雾灭火实验,探究达到最佳灭火效果的气液流量。结论可用于飞机货舱细水雾灭火系统的设计与改进,为飞机防火系统一些参数的设置提供了实验和理论基础。     

Importance of flow stratification and bubble aggregation in the separation zone of a dissolved air flotation tank

The importance of horizontal flow patterns and bubble aggregation on the ability of dissolved air flotation (DAF) systems to improve bubble removal during drinking water treatment were explored using computational fluid dynamics (CFD) modeling. Both analytical and CFD analyses demonstrated benefits to horizontal flow. Two dimensional CFD modeling of a DAF system showed that increasing the amount of air in the system improved the bubble removal and generated a beneficial stratified horizontal flow pattern. Loading rates beyond a critical level disrupted the horizontal flow pattern, leading to significantly lower bubble removal. The results also demonstrated that including the effects of bubble aggregation in CFD modeling of DAF systems is an essential component toward achieving realistic modeling results.     

Effect of turbulent gas-liquid contact in a static mixer on Cryptosporidium parvum oocyst inactivation by ozone

Static mixers may be used to dissolve gaseous ozone in water treatment facilities in order to provide protection against the waterborne parasite Cryptosporidium parvum. The objective of this study was to determine the effect of a brief exposure to turbulent gas-liquid mixing conditions in a static mixer on inactivation of C. parvum oocysts by ozone. Inactivation measured in an ozone contacting apparatus that employed a static mixer for ozone dissolution was compared to predictions based on a previously published kinetic model of C. parvum inactivation by dissolved ozone in gently stirred batch reactors. Although initial contact in the static mixer had no immediate effect on the oocysts, a 20% increase in the rate of inactivation during subsequent contact with dissolved ozone was observed. Increasing the degree of turbulence within the static mixer did not yield additional inactivation. Use of static mixers for dissolution of ozone in drinking water treatment systems may provide limited enhancement of C. parvum inactivation by dissolved ozone.     

柔性叶片附面层分离对气动性能的影响

为揭示柔性叶片受力后的变形状态对叶片气动性能的影响规律及原因,本文利用Fluent软件,采用RNGκ-ε湍流模型,选取柔性叶片受力变形过程中14个状态下的叶片作为研究对象并设定相同边界条件进行数值模拟计算,得到每组叶片上的压力分布、流场分布情况以及升力系数值;基于翼剖面理论和叶型附面层迁移理论,对比了14组叶片的升力系数值、附面层分离及涡流形成和发展的状态。结果表明:柔性叶片最佳迎角为20°,最佳曲率为0.019;曲率较大的叶片在接近后缘点区域吸力面上易发生附面层分离,会导致升阻比减小,造成能量损失,降低叶片的气动性能。     

The effects of bubble size on microflotation

Microflotation has been shown to be an efficient process for the removal of various colloidal sized impurities from water and waste water. Laboratory studies have shown that for this purpose very small bubbles are required. This study is to determine the effects of concentration of frother (ethanol) and collector (lauric acid) upon bubble size and upon efficiency of humic acid removal.Bubble sizes were measured photographically and humic acid removals determined spectrophotometrically. Ethanol was varied from 0.25 to 7.50 ml l^?1 and lauric acid from 0 to 100 mg l^?1 concentration. Initial humic acid concentration was 50 mg l^?1 and 0.0005 m aluminum sulfate was employed as a coagulant. All experiments were conducted at an adjusted pH of 7.5 in a 400 ml batch flotation cell. Ethanol produced a greater effect on bubble size than lauric acid; small additions of ethanol (ml l^?1) reduce bubble size drastically.The investigation showed a rapid decrease in microflotation removal efficiencies when bubble diameters exceed 55–60 μm. Efficient separations are extremely rapid, being essentially complete in 30 60 s.