跨音速喷嘴

首先用Ekspla公司的PL2143型皮秒脉冲激光器泵浦的PG401波长可调谐光学参量发生器，对248纳米激发的甲苯长波和短波荧光分量的比值进行了标定实验。然后采用LaVision公司两台图像增强器IRO加ImagerIntense相机。构成一套甲苯激光诱导荧光双色测量系统。激发光源采用KrF准分子激光器。利用甲苯荧光不同分量的比值，研究了跨音速喷嘴流动，识别不完全分子混合的特性。

采用LaVision公司最短帧间时间间隔可达115纳秒的跨帧相机，可以测量的速度上线可达十几公里/秒。本文的测试速度就达到了5倍音速。

采用德国LaVision的Imager Pro X4M CCD相机和蔡司ZEISS 50mm f/2 Makro 镜头，测量了亚音速高马赫数跨音速涡轮叶栅尾流的2D2C速度矢量场并和五孔探针的测量结果进行了对比分析。

采用NewWave公司GeminiII型Nd:YAG 双脉冲PIV激光器作光源。1016 × 1008 pixel 分辨率Kodak ES 1 Megaplus型相机做成像部件。LaVision的DaVis 软件平台做全部的数据处理，对跨音速矩形腔体流动中锯齿形阻流板性能的比例效应，进行了实验测量和研究。

采用德国LaVison公司的粒子成像测速PIV系统对喷嘴产生的跨声速流场的速度矢量场进行测量记录。测量系统由2kX2k像素CCD相机。光谱物理公司的PIV-400型双腔双脉冲激光器构成。激光器输出能量为350毫焦/脉冲。同时在远场对喷嘴产生的声场进行测量，分析研究等离子体主动控制喷嘴对湍流结构和声场的影响规律。

采用12台Lavision公司的Imager LX 2MP型PIV相机，在图像采集和控制软件平台DaVis构成了一套高空间分辨率体视层析3D3C速度场测量系统，并利用开系统实现了四脉冲层析粒子成像测速（Tomo-PIV）确定跨音速基流中的瞬时压力的研究。

采用LaVision公司基于成像测量的SprayMaster和Artium公司相位多普勒粒子干涉仪对植物油的但喷嘴和多喷嘴静电雾化过程进行了全局几何参量测量和单点喷雾液滴运动的二维速度和液滴粒径测量。

采用LaVision公司的增强型CCD相机对火焰喷射对象进行了测量。研究了喷嘴直径对火焰举升长度的影响。

采用美国Artium公司的无光纤式集成化DPSSL半导体泵浦的固体激光器构成的相位多普勒干涉仪测量系统，测量高速空气流中两个空气雾化喷嘴的喷雾中的液滴粒径和速度，并研究了其相互作用规律。

采用德国LaVision公司的高速时间分辨立体激光成像测速系统PIV和相位多普勒干涉仪系统，对曲面内壁喷嘴燃烧器中湍流喷雾火焰流场和液滴动力学进行了测量和研究

采用美国Artium公司的相位多普勒粒子分析仪和德国LaVision公司的智能成像软件平台，对螺旋式喷嘴的空气辅助雾化过程中雾化液滴的粒径进行了时间分辨和空间分辨测量。

采用LaVision公司的粒子成像测速系统和喷雾几何参量测量系统。对单点贫燃烧直喷射器的喷射速度场和几何形态进行了测量。研究了空气旋流器角度和喷嘴端部位置对喷雾特性的影响。

这是文章《使用等离子体制动器实现对高速高雷诺数喷射的流动和噪声控制》的第二部分。该文报道了在亚音速至跨音速区间进行的一系列实验结果。

Detailed atomization measurements in actual sprinklers are needed for properspray specification in suppression modeling and analysis. In basic pendantsprinkler configurations, the spray originates from two streams corresponding toflow deflected along the tines of the pendant and flow passing through the voidspaces between the tines. In this study, measurements of flow splits (betweenspace and tine streams), sheet breakup distances, drop size, and drop velocitymeasurements were performed over a range of sprinkler geometries and injectionpressures to characterize the near-field sprinkler spray. These detailedmeasurements were used to support the development of scaling laws describingthe effects of injector geometry and injection conditions on sprinkler dischargecharacteristics.

采用LaVision公司的高速相机和多参量数据采集和分析处理软件平台DaVis，对柴油JP-8喷雾的性能进行了测量分析。获得了喷雾的米氏散射和纹影成像数据。

The transient behaviour of the fuel spray from an air-assisted fuelinjector in a constant volume chamber has been investigatedexperimentally. The relative Sauter mean diameter (SMD) of thespray droplets was determined using planar laser inducedfluorescence (PLIF) and planar Mie scattering. Planar images ofthe ensemble averaged relative SMD with various injectionconditions were obtained by calculating the ratio between the twolaser light intensities at a given point. The penetration length andthe spray shape factor were also obtained. The ensembleaveraged results suggest the existence of vortices that are shedfrom the injector tip, and which entrain the smaller droplets.Results also show that the characteristics of the injector varyweakly with several particular injection parameters, notably thefuel injection pressure and the delay between fuel and airinjection.

Particle image velocimetry (PIV) is utilized with solid carbon dioxide (CO2)seeding material to conduct boundary layer measurements in the test section of the AirForce Research Laboratory’s Trisonic Gas-dynamics Facility (TGF), which has a 24 inchby 24 inch cross-section. Freestream velocity was set at Mach 0.3, Mach 0.5, or Mach0.8 while stagnation pressure ranged from 500 to 2400 pounds per square foot (psf). Highpressure liquid CO2 was directed through expansion nozzles into shroud tubes which ledto solidified particles in the wind tunnel stagnation chamber. Two different sets ofshroud tubes were used to modify the size of dry ice particles produced and the particlenumber density. Shroud tubes with an inside diameter (ID) of 0.824 inches providedgood particle count and coverage for stagnation pressures between 500 and 1500 psf,while 0.364 inch ID shroud tubes demonstrated good particle count and coverage forstagnation pressures over 1000 psf. Overall, the PIV results produced freestream velocitymeasurements and boundary layer profiles which compared well with expected values.After initial processing, turbulence data closely followed trends expected withinboundary layer, but levels were somewhat higher than anticipated. When the PIV datawas processed using elliptical interrogation regions, elongated in the streamwisedirection, resulting turbulence levels were much closer to expectations.

Pulsed jets have found a wide variety of applications in the area of flow control duringthe recent years. The goal of the current study is to identify the flow field and mixingcharacteristics associated with an incompressible circular jet through a flexible nozzle. Theflow was self-excited over a range of conditions and produced a pulsatile flow. The frequencyof excitation was found to be between 150-175Hz. Phase-locked and time averaged 2DParticle image Velocimetry (PIV) was used to study the dynamic characteristics of the flow.The flow field shows that two different modes could be excited depending on nozzlecharacteristic. The flapping mode was associated with alternate shedding of vortices. Thisintroduces strong steering of the jet to one side or the other. Turbulence, Jet spread andentrainment characteristics were far more superior to the non-flapping or a pulsed jet. Thesecond mode which was a non-flapping mode is associated with the formation of a counterrotating vortex pair. The turbulence associated with both these modes was convected alongwith the vortical structure in the flow. The jet vortices formed by the self-excited flow werenot just convected by the flow, but these determined the flow field and mixing characteristicsof the jet.

影响实验动物麻醉的因素 实验动物的麻醉是一项复杂系统的工作。正确的麻醉处理，是动物实验成功的有力保障。而麻醉处理不当，会给实验结果带来难以分析的误差。要想获得良好的麻醉效果，除掌握实验动物麻醉的基本知识和技术、遵循科学的麻醉程序外，还应了解影响实验动物麻醉的各种因素，如动物因素、环境因素等。

The effect on fuel consumption and emissions of switching from two-valve to single-valve EIVC operation inorder to generate swirl intake structures in a four-valve, pent-roof gasoline direct injection (GDI) engine hasbeen investigated. Mie imaging of the fuel spray propagation, along with PIV measurements of the intake flowfield have been taken in an optical engine, and fuel economy and emissions measurements have been made on athermodynamic engine with identical geometry and ancillary systems.The measurements show that fuel economy can be improved substantially when EIVC valve operation is employed,and results differ when only a single inlet valve is activated. Bulk swirl structures are generated in theengine cylinder which affect the atomisation and transportation of the fuel spray and engine performance. Forfuel injection after the inlet valve closing point, the reduction in shear forces and mixing from the intake airstructures is sufficient to cause engine misfires.

A coaxial jet was actively controlled by a MEMS-fabricated micro flap actuator nozzle. The effect ofdifferent control modes on secondary azimuthal instabilities and the evolution of streamwise vorticeswere investigated by applying stereoscopic PIV to the cross-stream plane of the jet. Forcing withnon-symmetric modes, in particular the least-stable helical mode, accelerates the evolution of thestreamwise vortices through the enhancement of azimuthal instabilities. Although forcing is appliedto the outer shear layer of the outer jet, the control effect is most pronounced in the inner shear layerof the inner jet. Unlike in the natural jet, streamwise vortices appear in the inner shear layer of thecontrolled jet. For forcing with the fundamental axisymmetric mode, a Strouhal number of the orderof unity maximise the azimuthal instabilities and hence the counts of the streamwise vortices. Thepresent result is in accordance with our previous experimental findings in the longitudinal plane,where the evolution of the primary vortices and mixing between the inner and the outer jets wereexamined through 2D-PIV and PLIF (Kurimoto et al., 2004, Active control of coaxial jet mixing witharrayed micro actuators. Transactions of the Japanese Society of Mechanical Engineers, pp. 31–38.)This emphasises the connection between primary and streamwise vortices and their significance in themixing enhancement process. It is also found that the azimuthal wavelength under the present controlscheme is almost the same as that of the natural jet and independent of the streamwise position.

This research project examines supersonic jets from nozzles representative of the practical variable-geometry convergent-divergent nozzles used on high-performance military aircraft. The nozzles employed have conical convergent sections, sharp throats and conical divergent sections. Nozzles with design Mach numbers of 1.3, 1.5, 1.56 and 1.65 are tested and the flow and acoustics examined. Such nozzles are found to produce a double-diamond shock structure consisting of two overlapping sets of shock cells, one cast from the nozzle lip and one cast from the nozzle throat. These nozzles are found to produce no shock-free condition at or near the design condition. As a result they produce shockassociated noise at all supersonic conditions. The shock cell spacing, broad-band shock-associated noise peak frequency and screech frequency all match those of more traditional nearly isentropic convergentdivergentnozzles.

采用LaVision公司已图像增强器为核心搭建的平面激光诱导荧光测试系统和喷雾分析系统，定量地研究了丙烷/液化石油气喷雾结构及其和环境压力的关系。

In this work the influence of the internal flow field on the liquid film was investigated. A strategy for reliablePIV measurements inside of nozzle channels with a height of only a few hundred micrometers and at flowvelocities of several m/s has been developed. These PIV measurements provided 2 dimensional snapshots of thevelocity field inside the nozzle as well as velocity- and fluctuation-profiles across the channel. The developmentof the channel flow could be observed along the channel length at laminar and partly turbulent flow conditions.Disturbances were introduced to the flow field by inserting a wire into the channel flow. PIV measurementsshowed the resulting change of the nozzle flow (in the wake of the wire and without wire, respectively). Theresulting effects on the free liquid film were observed using back-lit photographs and perpendicular lightsectionsthrough the film surface. In the case of the undisturbed nozzle, velocity fluctuations occurred mainly inthe boundary layer and the fluctuations in main streamwise direction were dominant. The free liquid film of thisnozzle was smooth at the exit and only at higher Re numbers the growth of surface waves could be observedfurther downstream. The nozzle with inserted wire showed a high level of velocity fluctuation in the center of theflow. Here, the fluctuations normal to the walls were of the same magnitude as the fluctuations in streamwisedirection. The liquid film of this nozzle was roughened directly below the nozzle exit, even at low Re numbers.The high level fluctuations normal to the wall are assumed to play the dominant role in this process. Thesemeasurements demonstrate the influence of the internal flow field on the liquid sheet. The results of the presentwork agree well with recent experiments of Heukelbach and Tropea [1] and supplement the existingexperimental data which for example can be used as input or validation of numerical simulations.

Crude Unit Column Overhead – CorrosionWater is usually injected in theoverhead piping to:• Help quench and scrub theoverhead vapors• Dilute acids formed• Prevent any salts or acids fromforming in the system

The entire process of atomization of the fuel in an internal combustion engine plays a very important role in determining the overall efficiency of these engines. A good atomization process could help the fuel to mix with the air properly leading to its efficient combustion, thereby reducing the emitted pollutants as well. The recent trend followed by the engineers focused on designing fuel injectors for more efficient atomization is to increase the atomization pressure while decreasing the nozzle orifice diameter. A consequence of this is the development of cavitation (formation of vapor cavities or bubbles in the liquid) inside the injector close to the nozzle. The main reason behind this is the sudden changes in the pressure inside the injector and these cavities or bubbles are usually formed where the pressure is relatively low.This work mainly focuses on studying the formation of cavitation and its effect on the velocity of the spray in the near nozzle region using asymmetrical transparent nozzle equipped with a needle lift sensor with nozzle diameter of 0.35 mm at 300 bar of injection pressure.The experiment consists in recording of several image-pairs, which are separated by about 300 ns, capturing the dynamics of the spray, a few millimeters from the nozzle in the direction of the flow. These image-pairs are then used to compute the velocity from the displacement of the liquid structures and ligaments by correlating the first image with the second. About 200 of such velocity graphs are then averaged to obtain a velocity map and is compared with the similar average velocity maps obtained at different times from the start of the injection. The angular spread of the spray from each of these images is calculated as well. The images showing cavitation in-side the injector are also recorded at these same instants of time so as to understand the effects of cavitation on the velocity and angular spread of the spray close to the nozzle.

This paper reports on the experimental investigation of the flame lift-off length for five different orificediameters (.0.100, .0.130, .0.160, .0.190, and .0.227 mm) of a diesel injector nozzle. The flame lift-offwas determined from the measurement of 308 nm OH chemiluminescence for different fuel injection pressuresusing commercial diesel fuel and a Common Rail fuel injection equipment of passenger car size. The fuelinjection pressures were 450, 900, and 1350 bar. The experiments were conducted at air pressures of 30, 50, 70,and 90 bar and at an air temperature of 750 K in a constant pressure spray chamber. It was observed that theflame lift-off length increases with increased injection pressure and increased orifice diameter.

Experimental velocity measurements of a low-speed jet, performed using time-resolvedtomographic PIV, are used to study the dynamics of large-scale structures and their soundradiation. The experimental results show the roll-up of axisymmetric vortices that pairdownstream, and subsequently lose their azimuthal coherence. Models of linear instabilitywaves using both steady laminar and mean-field base flows flow are applied. While goodagreement can be obtained for the vortex roll-up frequency in the near-nozzle region usingthe laminar base flow, non-linear effects must be included, via the mean field, in orderto capture the downstream evolution of both the fundamental and subharmonic (vortexpairing). The velocity fluctuations for both frequencies have a wave-packet structure withsome jitter in the form of modulations of the spatial extent and amplitude of the envelope.The sound radiation is modelled using a jittering wave-packet model, an shows agreementwith the exponential directivity shape of Laufer and Yen (J. Fluid Mech. 134, 1983).

MSE微粒喷浆冲蚀法是指压缩空气与浆料（水和固体粒子的混合物）在喷嘴中混合后，最终高速喷射到样品表面，产生相应的冲蚀痕迹。可快速评估各种涂层/材料表面性能，特别适合于目前难以测量的涂层。恒定的压缩空气与浆料对材料表面进行冲蚀，材料磨损量随表面强度而变化。再将磨损量的变化转换成磨损率，以此来评估和对比各种材料表面强度，是世界最新的材料评估方法，特别适用于超硬、超软、透明、超软、复合涂层等。日本涂层/材料综合性能评价试验机（MSE微粒喷浆冲蚀法）——超硬、超薄、透明、超软、复合涂层的最新评估方法，适用所有涂层、镀层、镀膜。可用于评估光学涂层、DLC、汽车零部件、滑动表面、液晶膜、CVD/金刚石、切削工具等。可用于评价：涂层强度数值话、表面至基体的强度变化、涂层与涂层/涂层与基体的结合力、评价镀膜工艺、评价涂层的均匀度。

功能材料的喷墨打印在广告、OLED 显示器、电子印刷和其他需要高精度、无掩模、直写沉积技术的专业用途中显示出广泛的应用。然而，分散在油墨中的功能材料的沉降风险限制了其进一步实施。氧化铬 (Cr2O3) 是一种高性能耐火、耐磨、耐腐蚀无机材料，可用于模拟绿叶的太阳光谱反射特性以达到伪装目的。应用以 Cr2O3 为颜料的喷墨打印技术可以显着简化从设计到涂覆新迷彩图案的过程并降低成本。然而，Cr2O3 的喷墨打印却显见报道，因为基于金属氧化物颗粒的墨水分散稳定性差，容易结块和沉淀，导致打印时喷嘴堵塞。 在颜料油墨制备的步骤中，颜料被研磨至纳米级并使用如树脂、分散剂等助剂分散到溶剂中（自上而下的方法）。该类油墨沉降的风险主要是由于固体颜料颗粒在系统中是人为分散而不是原位生成造成的。为了克服这个问题，该论文提出了自下而上制备颜料油墨，通过控制生长反应，从而可以一步原位制备具有长期分散稳定性的油墨。