激光脉冲参数对冲击点火的影响

针对激光脉冲参数对冲击点火的影响进行理论分析和数值模拟.首先从冲击波的产生和碰撞过程出发,理论分析冲击脉冲峰值功率、脉宽和上升沿时间对点火的影响;然后通过数值模拟,以点火时间窗口作为评价标准,验证理论分析结果.研究表明:冲击脉冲峰值功率是点火成败的关键因素之一,脉冲宽度则需达到百皮秒以提供足够的点火能量,上升沿时间在小于600 ps的情况下不会对点火造成明显影响. 关键词： 冲击点火 激光冲击脉冲 点火时间窗口     

氢气对正丁烷/空气混合物催化着火的热作用和化学作用

通过对正丁烷/氢气/空气混合物在Pt 催化表面的详细反应机理分析, 研究了氢气添加对正丁烷/空气混合物催化着火过程的影响. 研究发现, 在正丁烷/空气混合中添加氢气有助于正丁烷在更低的温度下实现催化着火, 而且不同的氢气添加量对混合物的着火温度和着火过程呈现不同的影响: 当氢气添加量较小时, 氢气的作用主要呈现为热影响; 而当氢气添加量较大时, 氢气的作用主要呈现为化学影响. 这些结果与实验结果是一致的. 本文进一步确定了发挥不同作用的氢气添加量的范围, 并分别对热作用和化学作用情况下的着火启动反应进行了动力学分析.     

2,2‐Bis(5‐tetrazolyl)propane as Ligand in Energetic 3d Transition Metal Complexes

This contribution covers the preparation and characterization of 2,2‐bis(5‐tetrazolyl)propane (5‐DTP) ( 1 ). The bridged bitetrazole is used as a neutral nitrogen‐rich ligand in 3d transition metal(II) based complexes for the first time and can be synthesized via [2+3] cycloaddition from sodium azide and dimethylmalononitrile. The combination with different anions (e.g., perchlorate, nitrate, sulfate, and chloride) yields materials with widely varying physicochemical properties. The obtained coordination compounds were characterized using low‐temperature single‐crystal X‐ray diffraction (except 14 ), IR spectroscopy, elemental analysis, and DTA (except 16 ). The sensitivities toward external stimuli (impact and friction) were determined according to the Bundesamt für Materialforschung und ‐prüfung (BAM) standard methods together with its sensitivities against electrostatic discharge (except 16 ). Complexes 10 and 14 were characterized in laser ignition experiments. For determination of the compounds' deflagration to detonation transition (DDT) capability, hot plate and hot needle tests were performed for the zinc(II) and copper(II) perchlorate complexes.     

典型静电放电火花点燃能力测试研究

通过对静电放电火花点火过程的物理特征研究，分析与总结了典型静电放电火花的点燃能力．根据放电火花的产生条件和形状特点，静电放电火花分为电晕放电、刷形放电、料仓堆表面放电、人体放电、火花放电和传播型尉形放电6种典型放电类型．根据静电放电火花的火花空间分布范围和火花持续时间，研究了静电放电火花点燃可燃物的能力．典型静电放电火花的实际点火能量为：电晕放电不大于0．025mJ，刷形放电不大于3mJ，料仓堆表面放电不大于10mJ．人体放电不大于30mJ，火花放电不大于1J，传播型刷形放电不大于10J．     

Engine Modelling for Control Applications: A Critical Survey

In earlier work published by the author and co-authors, a dynamic enginemodel called a Mean Value Engine Model (MVEM) was developed. This model isphysically based and is intended mainly for control applications. In itsnewer form, it is easy to fit to many different engines and requires littleengine data for this purpose. It is especially well suited to embedded modelapplications in engine controllers, such as nonlinear observer basedair/fuel ratio and advanced idle speed control. After a brief review of thismodel, it will be compared with other similar models which can be found inthe literature. The attempt will be made to point out the differencesbetween the new modified MVEM and those developed elsewhere. In particular,the questions of fitting simplicity and general applicability are to betreated.     

煤粒均相着火规律的研究

煤粒均相着火规律的研究张军，傅维标（清华大学工程力学系北京１０００８４）关键词均相着火，简化模型，预报１前言煤粉颗粒既能发生均相着火，又能发生非均相着火山。对非均相着火，许多学者进行了研究，取得了很多有价值的成果。均相着火由于比较复杂，一直发展缓慢。...     

油页岩和半焦燃点的研究

使用LCT-1型的TG-DTA联合热分析仪与CO/CO_2 GQS-08型红外分析仪相结合,测定了抚顺、茂名和约旦三种油页岩及其半焦的燃点,提出均相着火和非均相着火机理。当进行非均相着火时,着火发生在油页岩或半焦的表面,当进行均相着火时,着火发生在包围着样品的气层中,样品进行哪种着火机理,与试样的化学和物理性质以及燃烧条件有关。通过在计算机上的关联,获得这三种油页岩和半焦的燃点数学模型,用该模型预测燃点时理论值与实测值平均相对误差:对油页岩<2.0%;对半焦<5.8%。     

加压下煤的着火特性的研究 Ⅰ.着火特性的影响因素

采用带程序升温控制的、可在加压下测定煤着火特性的装置,在程序升温速度(7.5℃/min)和加压条件下,测定了影响煤和煤焦着火特性(着火温度与燃烧时间)的各种因素,这些因素包括煤的粒度、试样质量、空气流量、系统压力和氧分压等。试验表明,这些因素的影响与煤中挥发份有一定的关系,着火温度和燃烧时间随总压或氧分压增加而下降。