二维高超声速钝体激波层紫外辐射的实验观察

利用光学多道分析仪，在JF-10氢氧爆轰驱动高焓激波风洞上测量了二维钝体驻点的发射光谱．实验结果表明，在200~280nm的波长范围内，辐射主要来自NO的γ系，同时还分辨出了OH的A-X跃迁、N_2~+的B-X跃迁和烧蚀金属的原子线辐射．

An Experimental Study of Kerosene Combustion in a Supersonic Model Combustor Using Effervescent Atomization

Investigation of kerosene combustion in a Mach 2.5 flow was carried out using a model supersonic combustor with cross-section area of 51 mm × 70 mm and different integrated fuel injector/flameholder cavity modules. Experiments with pure liquid atomization and with effervescent atomization were characterized and compared. Direct photography, Schlieren imaging, and planar laser induced fluorescence (PLIF) imaging of OH radical were utilized to examine the cavity characteristics and spray structure. Schlieren images illustrate the effectiveness of gas barbotage in facilitating atomization and the importance of secondary atomization when kerosene sprays interacting with a supersonic crossflow. OH PLIF images further substantiate our previous finding that there exists a local high-temperature radical pool within the cavity flameholder, and this radical pool plays a crucial role in promoting kerosene combustion in a supersonic combustor. Under the same operation conditions, comparison of the measured static pressure distributions along the combustor also shows that effervescent atomization generally leads to better combustion performance than the use of pure liquid atomization. Furthermore, the present results demonstrate that the cavity characteristics can be different in non-reacting and reacting supersonic flows. As such, the conventional definition of cavity characteristics based on non-reacting flows needs to be revised.

超音速燃烧室氢氧基平面激光诱导荧光测量

用平面激光诱导荧光(PLIF)技术测量了氢/空气和煤油/空气超音速燃烧室氢氧基的荧光以及背景辐射光的图像.实验结果表明,PLIF是鉴别对燃烧性能起关键作用的燃料/空气混合过程的有效手段,发现在超音速燃烧室中PLIF氢氧基主要集中在凹腔区域,这有助于解释凹腔对超音速燃烧起稳定作用的机理.

Shock tube study of JP-10 ignition delay time

JP-10 (exo-tetrahydrodicyclopentadiene, C10H16) ignition delay times were measured in a preheated shock tube. The vapor pressures of the JP-10 were measured directly by using a high-precision vacuum gauge, to remedy the difficulty in determining the gaseous concentrations of heavy hydrocarbon fuel arising from the adsorption on the wall in shock tube experiments. The whole variation of pressure and emission of the OH or CH radicals were observed in the ignition process by a pressure transducer and a photomultiplier with a monochromator. The emission of the OH or CH radicals was used to identify the time to ignition. Experiments were performed over the pressure range of 151-556 kPa, temperature range of 1000-2100 K, fuel concentrations of 0.1%-0.55% mole fraction, and stoichiometric ratios of 0.25, 0.5, 1.0 and 2.0. The experimental results show that for the lower and higher temperature ranges, there are different dependency relationships of the ignition time on the temperature and the concentrations of JP-10 and oxygen.

促进剂对高碳数碳氢燃料点火特性的影响

在JP-10和煤油点火特性激波管实验基础上,进行了促进剂CH_3NO_2、CH_2Cl_2对JP-10和煤油点火特性影响的实验.在预加热激波管上采用缝合运行技术,获得了近7ms的实验时间.采用单色仪和光电倍增管记录点火过程中OH自由基在306.5nm发射谱强度变化作为点火发生的判据.当促进剂加入量约为JP-10的10%～20%(摩尔比),质量比为5%～12%时,实验观测到明显的点火促进作用.在1100K时,添加10%(摩尔比)CH_3NO_2使JP-10的点火延时时间缩短了70%.当CH_3NO_2的加入量占煤油的10%～15%(摩尔比),质量比约为5%～6%时,对煤油点火有明显的促进作用,在1000K时使煤油点火延时时间缩短了50%.

硅烷对JP10和煤油点火特性影响的激波管研究

在JP10和煤油点火特性激波管实验的基础上,实验研究了硅烷对这两种典型高碳数碳氢燃料点火特性的影响.在预加热到70℃的激波管上,采用缝合运行条件获得了近7ms的实验时间,将实验延伸至低温区.采用气相色谱分析和高精度真空仪直接测定压力相结合的方法,确定了燃料气相浓度,解决了高碳数碳氢燃料点火激波管实验时由于管壁吸附影响燃料气相浓度确定的困难.实验记录了点火过程中OH自由基发射强度变化,并作为判断点火发生的标志.实验温度范围880～1 800K,压力范围0.16～0.53MPa.当硅烷加入量约为燃料的10%～15%(摩尔比),质量比为2%～3%,观测到明显的点火促进作用.该研究对超燃研究中发动机设计、燃料选择等方面具有直接的工程意义,也可用于检验燃烧化学动力学模型的合理性.

锰含量对LiNi_(0.85-x)Co_(0.15)Mn_xO_2结构及形貌的影响

采用共沉淀法先合成出氢氧化物前驱体Ni0.85-xCo0.15Mnx(OH)2,其中X=0、0.1、0.2和0.4,前驱体与Li2CO3在空气气氛中固相烧结制得正极材料LiNi0.85-xCo0.15MnxO2。用XRD、SEM研究了锰含量对材料结构和形貌的影响。研究发现,LiNi0.85Co0.15O2的X射线衍射图中存在微量第二相,而锰掺杂有利于减小反应过程中锂离子损失和镍离子占据锂位,容易形成有序层状结构材料。随着Mn离子替代Ni离子量的增加,晶胞参数a减小,晶胞参数c、c/a及I003/I104值增大。SEM结果表明前驱体和最终产物形貌均随锰含量增加颗粒均匀性增强,粒子尺寸变小,粒径分布变窄。

An Experimental Study of Kerosene Combustion in a Supersonic Model Combustor Using Effervescent Atomization

Investigation of kerosene combustion in a Mach 2.5 flow was carried out using a model supersonic combustor with cross-section area of 51 mm?70 mm, with special emphases on the characterization of effervescent atomization and the flameholdering mechanism using different integrated fuel injector/flameholder cavity modules. Direct photography, Schlieren imaging, and Planar Laser Induced Fluorescence (PLIF) imaging of OH were utilized to examine the cavity characteristics and spray structure, with and without gas barbotage. Schlieren images illustrate the effectiveness of gas barbotage in facilitating atomization and the importance of secondary atomization when kerosene sprays interacting with a supersonic crossflow. OH-PLIF images further substantiate our previous finding that there exists a local high temperature radical pool within the cavity flameholder and this radical pool plays a crucial role in promoting kerosene combustion in a supersonic combustor. The present results also demonstrate that the cavity characteristics can be different in non-reacting and reacting supersonic flows. As such, the conventional definition of cavity characteristics based on non-reacting flows needs to be revised.

天然纳米结构材料——江苏盱眙凹凸棒土的特性及开发应用前景

本文对江苏盱眙凹凸棒土的样品进行比表面积测量,比表面积230m2／g。用X光衍射和X光荧光分析表明,此样品主相为坡缕石(Palygoskite),其分子式:(Mg,Al)5(Si,Al)8O20(OH)2?8H2O,这种颗粒的集合体具有特有的毡状结构,旧名山软木。显微结构棒晶长约1μm,直径约20nm,是天然纳米结构材料。本文指出,利用凹凸棒土比表面积大有很强的吸附性,开发出无毒粮食保鲜剂和无抗菌素的胃肠药;利用凹凸棒土一维针状纳米结构,对其表面进行改性,减弱凹凸棒土晶束之间的作用力,以利于在聚合物中分散,提高聚合物物理性能,开发凹凸棒土在聚合物材料上的应用。

碳氢燃料超音速燃烧的数值研究

本文对CH_4横向喷入超音速高温空气主流的二维流场进行了数值模拟，对CH_4-O_2的六方程反应模式进行了检验，借以对混合与燃烧过程的现象与机理加以研究，并与单方程反应模型及H_2横向喷射的情况进行了对比。得到了较为理想的结果。本文采用二维雷诺平均全N-S方程进行计算，采用热完全气体模型，用Baldwin-Lomax代数涡粘性湍流模型来模拟湍流效应。假定N_2不参加反应，CH_4-O_2反应机制选取六个基本反应，以及九个组元O、O_2、CH_3、CH_4、OH、CHO、CH_2O、CO和CO_2，应用空间二阶精度Harten-Yee隐式TVD格式，采用化学源项点隐的全隐方法数值求解。本文对多种超音速空气主流及边界条件的工部进行了数值模拟，并对其流场进行了分析。针对工作中出现的问题，提出了对下一步工作的展望。

Influence of HCl on CO and NO emissions in combustion

The influence of HCl on CO and NO emissions was experimentally investigated in an entrained flow reactor (EFR) and an internally circulating fluidized bed (ICFB). The results in EFR show the addition of HCl inhibits CO oxidation and NO formation at 1073 K and 1123 K. At the lower temperature (1073 K) the inhibition of HCl becomes more obvious. In ICFB, chlorine-containing plastic (PVC) was added to increase the concentration of HCl during the combustion of coal or coke. Results show that HCl is likely to enhance the reduction of NO and N2O. HCl greatly increases CO and CH4 emission in the flue gas. A detailed mechanism of CO/NO/HCl/SO2 system was used to model the effect of HCl in combustion. The results indicate that HCl not only promotes the recombination of radicals O, H, and OH, but also accelerates the chemical equilibration of radicals. The influence of HCl on the radicals mainly occurs at 800-1200 K. (C) 2009 Elsevier Ltd. All rights reserved.

Entanglement purification based on photonic polarization parity measurements

We present an entanglement purification protocol for photonic mixed entangled states based on the two-mode polarization nondemolition parity detectors. Without the use of the controlled-NOT (CNOT) operations, the efficiency of our protocol can nearly approach that of the CNOT protocol. The total successful probability of our protocol can be nearly enhanced to the quantity twice as large as that of the linear-optics-based protocol. Besides, our protocol adopts common photon detectors rather than the sophisticated single-photon detectors required in the linear-optics-based protocol.