甲烷-煤尘爆炸物火焰传播特性

 在10 m³的爆炸罐中对体积分数为8%的甲烷和75 g/m³煤尘的混合物进行了系统的燃烧爆炸实验。分别利用光测方法和压力方法得到了爆炸物的层流燃烧速度、火焰传播速度、火焰厚度、马克斯坦长度以及爆炸特征值的变化规律。结果表明,在常温常压下,当点火能为40 J时：利用光测法得到的8%甲烷与75 g/m³煤尘混合物的燃烧速度为0.437 m/s,而根据压力-时间关系得到的混合物燃烧速度为0.459 m/s,两者符合较好;用火焰厚度与马克斯坦长度判定的火焰发展趋势相同,即向外传播的火焰趋于稳定;爆炸物的爆炸特征值最大值出现在0.5 m处,壁面的爆炸特征值偏小。     

气-液-固三相体系云雾爆轰特性的实验研究

在内径为0.2m、高5.4m的大型立式激波管内,同时对液体燃料和黑索金(RDX)粉末进行抛撒,采用底部直接起爆,得到了RDX-液体燃料-空气三相体系的爆压和爆速,利用烟熏技术得到了爆轰波的胞格结构、尺寸及长宽比。结果表明:90#溶剂油-空气两相体系的平均爆压为5~6 MPa,可以将其作为燃料-空气炸药的主燃料;向该燃料中添加硝酸异丙酯(IPN)可以降低其临界起爆能,添加RDX能够提高体系的爆速和爆压。此外,通过理论分析结合实验验证得出,多相爆轰的临界起爆能和爆轰胞格尺寸之间存在与气相爆轰类似的关系。     

Experimental Diagnosis on Combustion Characteristic of Shock Wave Focusing Initiation Engine

A shock wave focusing initiation engine was assembled and tested in an experimental program. The effective pyrolysis rate of the pre-combustor was evaluated over a range of supplementary fuel ratio in this paper. Results highlight two operational modes of the resonant cavity: (1) pulsating combustion mode, (2) stable combustion mode. The appearance of the two combustion modes is jointly affected by the flow and the structural characteristic value of the combustion chamber. This paper uses images, time-frequency analysis, and nonlinear time series analysis methods to identify and distinguish these two combustion modes. It is believed that the interaction between the combustion chamber and the supply plenum is the probable reason for different combustion modes. The experiment has found that structural parameters and import flow parameters have an impact on the initiation of the combustion chamber. Increasing the injection pressure can appropriately broaden the fuel-rich boundary of initiation. Low equivalence ratio and high injection pressure can also appropriately increase the combustion working frequency in a small range. From the perspective of pressure utilization, under the premise of ensuring successful initiation, injection pressure should not be too high.     

激光驱动飞片冲击引爆炸药的计算

 在Gurney方程和考虑金属相变状态方程的基础上， 提出了一种激光驱动飞片运动的计算模型。这种模型能确定与炸药临界起爆相关的参数，诸如沉积的激光能量、烧蚀层和飞片的厚度以及飞片飞行的距离等等。计算的结果与实验相符。在本模型中可以对电离、烧蚀及二维效应作进一步的考虑。     

激光拉曼光谱技术对氯代有机混合物的快速检测研究

为实现对有机物混合物的快速、无损检测,提出一种基于激光拉曼光谱技术的二维分析方法。研究结果表明,采用532 nm波长激光作为激发光源,观测到236.2,348.9,449.4,513.6 cm-1四条振动拉曼谱线,且这些谱线的强度比为6.4∶1.7∶9.4∶1.0,可确定四氯乙烯的存在。观测到707.5,1 087.9,1 175.8, 3 078.6 cm-1四条振动拉曼谱线,其强度比为9.6∶6.4∶1.0∶3.9,可确定氯苯的存在。即通过综合分析特征谱线及若干特征谱线的强度比,可快速判断有机混合溶液中某种物质的存在。在定量分析方面,采用多光谱分析结合最小二乘法拟合提高了测量的可靠性,所测样品浓度的准确率为98.4%。本研究为有机物混合物成分识别和浓度探测提供了一套可行的光谱测量方法,有着十分重要的应用前景。     

Initiation of Kerosene Combustion in a Supersonic Air Flow by a Bunch of Gas-Dynamic Pulses

Doklady Physics - In this paper, we propose a method to initiate combustion of kerosene in a supersonic air flow in part of a combustion chamber with a constant cross section and experimentally...     

混合比和燃烧组分浓度测量系统的原理和设计(英文)

研制了一套新型测量系统,系统由YGA激光器、染料激光器、晶体组、CCD摄像机、图像处理系统和附件等组成.与反斯托克斯拉曼散射、激光诱导荧光、平面激光诱导荧光和拉曼散射系统相仿,该系统具有测量燃烧组分浓度的功能.此外,它还可以测量喷嘴氧化剂和燃料的混合比分布,测量参数是给定时间内给定区域的统计值.系统已经成功用于液体火箭发动机气/气喷嘴、气/液喷嘴和液/液喷嘴喷雾场混合比分布特性研究,并已用于CO、CO2、No、NO2、OH和H2O(g)等燃烧产物组分的浓度测量,这种新系统将成为液体火箭发动机工作过程研究的有力分析工具.     

混合比和燃烧组分浓度测量系统的原理和设计

研制了一套新型测量系统，系统由YGA激光器、染料激光器、晶体组、CCD摄像机、图像处理系统和附件等组成．与反斯托克斯拉曼散射、激光诱导荧光、平面激光诱导荧光和拉曼散射系统相仿，该系统具有测量燃烧组分浓度的功能．此外，它还可以测量喷嘴氧化剂和燃料的混合比分布，测量参数是给定时间内给定区域的统计值．系统已经成功用于液体火箭发动机气／气喷嘴、气／液喷嘴和液／液喷嘴喷雾场混合比分布特性研究，并已用于CO、CO2、NO、NO2、OH和H2O（g）等燃烧产物组分的浓度测量，这种新系统将成为液体火箭发动机工作过程研究的有力分析工具．     

Critical Conditions of Combustion of a Gas Mixture over a Planar and Honeycomb Porous Matrices

The flammability limits for the combustion of gas mixtures over planar and three-dimensional (perforated) matrices were analyzed theoretically. It was demonstrated that the flame temperature can be substantially decreased (by a factor of 1.5 to 2.0) compared to the adiabatic flame temperature, an effect that makes it possible to significantly extend the limits of combustion over a honeycomb matrix. The flammability limits were shown to widen with increasing pressure.     

激波管内燃料两相云雾爆轰的实验研究

 在立式激波管中采用压力传感器和烟迹技术实测了6种碳氢燃料（环氧丙烷、硝酸异丙酯、C₅~C₆、己烷、庚烷和癸烷）与空气混合物的临界起爆能和爆轰波胞格尺寸。结果表明，燃料气液两相云雾爆轰的临界起爆能与当量比呈“U”形曲线关系，并且最敏感的起爆点在富燃料一侧，这与气相爆轰结论是一致的；由三波点运动的烟迹记录结果分析得出，雾滴的碎解、蒸发汽化过程以及燃烧区前导是控制气液两相云雾爆轰的作用机制。     

强激光对燃烧室壳体的热-力毁伤研究

基于ANSYS有限元软件, 按有无内压作用, 分别对激光辐照下燃烧室壳体的温度场、热应力、应变与损伤进行了计算与分析.分析表明, 壳体的温度场分布与光束的功率分布一致, 光斑中心温度最高.壳体中应力最大值不在光斑中心, 而是位于光斑边缘处, 在壳体吸收的激光功率密度超过1 000 W/cm²时, 壳体中应力大于材料的强度极限, 壳体均会发生软化.在存在内部燃气压力的情况下, 壳体应力会产生局部集中, 沿壳体环向表面通过光斑中心中轴线区域很有可能裂口;相比较无内压的壳体, 存在内压的壳体中的应力和产生的形变均大于无内压时的壳体.因此, 为达到相同的毁伤效果, 在存在内压的情况下, 可以适当的降低激光的辐照强度.     

Quantitative and Spatially Resolved Measurement of Atomic Potassium in Combustion Using Diode Laser

A compact optical setup for quantitative and spatially resolved measurement of atomic alkali concentration in combustion is demonstrated.Tunable diode laser absorption spectroscopy and laser-induced fluorescence are combined using a single continuous wave diode laser to measure the line-integration concentration and the relative distribution simultaneously,thereby obtaining the absolute concentration distribution along the laser beam.The results indicate the good performance of this method for one-dimensional quantitative measurement.     

强激光对燃烧室壳体的热-力毁伤研究

基于ANSYS有限元软件,按有无内压作用,分别对激光辐照下燃烧室壳体的温度场、热应力、应变与损伤进行了计算与分析.分析表明,壳体的温度场分布与光束的功率分布一致,光斑中心温度最高.壳体中应力最大值不在光斑中心,而是位于光斑边缘处,在壳体吸收的激光功率密度超过1 000W/cm2时,壳体中应力大于材料的强度极限,壳体均会发生软化.在存在内部燃气压力的情况下,壳体应力会产生局部集中,沿壳体环向表面通过光斑中心中轴线区域很有可能裂口;相比较无内压的壳体,存在内压的壳体中的应力和产生的形变均大于无内压时的壳体.因此,为达到相同的毁伤效果,在存在内压的情况下,可以适当的降低激光的辐照强度.     

基于激光诱导击穿光谱技术的混合溶液重金属元素检测

利用激光诱导击穿光谱技术对混合溶液中的Cu,Mg,Zn和Cd四种重金属元素进行实验测量,实验中采用波长为1 064 nm,脉宽10 ns,重频10 Hz的激光器。在蒸馏水中加入CuSO₄,Mg(NO₃)₂,Zn(NO₃)₂和Cd(NO₃)₂四种溶质,配置7种不同Cu,Mg,Zn和Cd浓度的混合溶液,采用统计探索性数据分析方法处理LIBS实验数据,得到水溶液中Cu,Mg,Zn和Cd元素的定标曲线,拟合度系数R2均大于0.99,计算出Cu,Mg,Zn和Cd四种元素的检测限分别为5.62,4.71,13.67和4.43 ppm,单一溶质CuSO₄溶液中的Cu元素的LOD值为3.98 ppm。最后对单一溶质和四种溶质的LIBS检测结果差异进行了分析。研究结果表明激光诱导击穿光谱技术在环境水污染多种重金属元素检测方面具有潜在的应用前景。     

Initiation Thresholds and Dynamic Characteristics of an Explosion for Thin Samples of PETN-Al Composites under Laser Irradiation

Technical Physics - In this paper, we measured thresholds Hcr of explosive decomposition of thin (h = 1 mm) samples of PETN-Al composites with densities in the range of ρ = 0.9–1.7 g/cm3...     

The Process of a Laser-Supported Combustion Wave Induced by Millisecond Pulsed Laser on Aluminum Alloy

We study the process of a laser-supported combustion wave(LSCW) when an aluminum alloy is irradiated by a millisecond pulse laser based on the method of laser shadowgraphy.Under the condition of different laser parameters,the obtained results include the velocity,ignition threshold of LSCW and the variation law.The speed of LSCW increases with the laser energy under the same irradiation laser pulse width,and the speed of LSCW reduces with the increase of the laser pulse width under the same irradiation laser energy.Moreover,the ignition time of LSCW becomes shorter by increasing the laser number of the pulse and is not effected by changing the frequencies,when keeping the laser pulse width and energy unchanged.The results of the study can be applied in the laser propulsion technology and metal surface laser heat treatment,etc.