一类燃烧方程的马赫数极限

采用能量估计和Helmholtz分解方法证明了在二、 三维空间上, 当马赫数趋于零时, 可压缩燃烧方程解的极限收敛到不可压缩燃烧方程的解.     

煤粉炉内扩散火焰关于大尺度涡的“砂轮”效应初探

以110MW、四角切向喷射的煤粉动力锅炉为对象,借助CFX4.2软件,在α-250工作站对该型锅炉的燃烧过程开展了数据模拟研究,研究发现：在该型炉膛内存在某种由准强制涡和准自由涡所组成的涡结果,这些涡均属于大尺度涡（非亚格子涡）;在这些准强制涡和准自由涡即大尺度涡之间以及某些涡与固壁或涡与喷射气流之间因扩散燃烧及强剪切而导致局部火焰增强现象即所谓“砂轮”效应,从Zeldovich转换和广义Reynolds比拟及粘性耗散的角度,定性地分析了这一效应。     

RBCC二元进气道起动性能数值模拟研究

根据RBCC动力飞行器的弹道特点,RBCC进气道的设计点马赫数往往较高,导致低马赫数下的起动性能较差。针对某宽工作马赫数范围,设计点Ma=5的RBCC变几何二元进气道,对其引射-亚燃转级马赫数附近的起动性能进行了数值研究。数值模拟计算表明:(1)进气道工作于低马赫数下(即非设计点),不起动时唇口附近存在一道"λ"激波产生溢流和激波损失,导致性能相对起动时有明显下降;(2)进气道内收缩比越大自起动马赫数越高;相同内收缩比下"脉冲起动"比自起动容易;(3)采用吸除措施可以降低进气道的自起动马赫数,改善进气道的起动特性;(4)采用调节进气道唇口的措施可以在牺牲少量流量的代价下实现进气道的自起动,同时提高进气道的总压恢复系数。     

试论在非惯性系中惯性力的真实性

本文对在非惯性系中引入的惯性力,从理论上,工程实践上,以及它所产生的效果上,论证了它是一种真实的力。     

爆轰波在金属板面斜反射现象的实验观测与分析

采用脉冲X射线照相、高速扫描照相、压阻测压及电探针测时等技术对B炸药-铜板系统中爆轰波斜反射现象进行了系统观测.确认在入射角φ_0=65°时的确发生了非正规斜反射(马赫反射)现象.但压阻测压表明,此时的压力却比理想爆轰理论的预告值低约30％.这与Los Alamos实验室学者们获得的结果极为相似.结合二维数值计算结果,对这一现象进行了分析,并提出了见解。     

Reception and discovery: the nature of Johann Wilhelm Ritter’s invisible rays

Ultraviolet radiation is generally considered to have been discovered by Johann Wilhelm Ritter in 1801. In this article, we study the reception of Ritter’s experiment during the first decade after the event—Ritter’s remaining lifetime. Drawing on the attributional model of discovery, we are interested in whether the German physicists and chemists granted Ritter’s observation the status of a discovery and, if so, of what. Two things are remarkable concerning the early reception, and both have to do more with neglect than with (positive) reception. Firstly, Ritter’s observation was sometimes accepted as a fact but, with the exception of C. J. B. Karsten’s theory of invisible light, it played almost no role in the lively debate about the nature of heat and light. We argue that it was the prevalent discourse based on the metaphysics of Stoffe that prevented a broader reception of Ritter’s invisible rays, not the fact that Ritter himself made his findings a part of his Naturphilosophie. Secondly, with the exception of C. E. Wünsch’s experiments on the visual spectrum, there was no experimental examination of the experiment. We argue that theorizing about ontological systems was more common than experimenting, because, given its social and institutional situation, this was the appropriate way of contributing to physics. Consequently, it was less clear in 1810 than in 1801 what, if anything, had been discovered by Ritter.     

喷管内流体流动状况的理论分析和数值模拟

对喷管内流体的流动状况做了详细的理论分析,主要对喷管中管道截面积和几个状态参数之间关系进行分析,如管道截变化对流体流速、马赫数、压力、温度等参数的影响,得到喷管截面的变化规律不仅仅取决于流速的变化情况,而且还与其他状态参数有关,尤其是马赫数.最后通过模拟缩放喷管与理论进行对比分析,表明模拟是正确的,且管道内气体流场特性的数值模拟在实际工程中是可行的.     

测量单模振动的时间平均曝光法

采用ＭａｃｈＺｅｈｎｄｅｒ干涉仪测量简谐振动．引入圆柱形透明介质对物光束调制,产生一组带有振动信息的散斑干涉条纹,由此确定振动参数,同时提高测量灵敏度．     

喷气织机封闭式喷气引纬管道内气流的测试分析

本文以封闭式喷气引纬管道为研究对象,分析计算了喷嘴内气流速度的变化规律,得出一组喷嘴内气流马赫数 M 与位置 x 的关系曲线;并分析研究了封闭引纬管道内气流速度的变化规律以及气流速度的计算方法,并对封闭引纬管道内气流速度进行了测试分析。     

Mach and Hertz’s mechanics

The place of Heinrich Hertz’s The principles of mechanics in the history of the philosophy of science is disputed. Here I critically assess positivist interpretations, concluding that they are inadequate.There is a group of commentators who seek to align Hertz with positivism, or with specific positivists such as Ernst Mach, who were enormously influential at the time. Max Jammer is prominent among this group, the most recent member of which is Joseph Kockelmans. I begin by discussing what Hertz and Mach had to say about one another, and I specify certain respects in which their views are indeed similar. I then go on to detail their differences, looking at Hertz’s attitude to the atomic theory, to the mechanical world-view, to simplicity, to unobservables and metaphysics, and his objections to Newtonian forces. I conclude that the positivist interpretation of Hertz’s mechanics significantly overplays its similarities to Mach’s views.