基于风险的防爆起重机防爆系统安全检验技术研究

简要介绍了基于风险的检验技术及防爆起重机的防爆技术,分析了防爆起重机运行过程中可能产生电气、机械及静电引燃源。采用基于专家调查法与层次分析法的定性分析方法对防爆起重机电气与机械引燃源定性风险分析评估,并制定防爆检验策略与检验要求。同时,对机电类特种设备风险研究提出了相关建议。     

制造信息化的分析与研究

论述了制造信息化的内涵、现状、存在的问题和对我国制造业的影响，认为制造信息化主要是指产品设计、制造及底层设备的信息化，隶属于制造业信息化范畴，进而提出制造信息化应该与管理、决策信息化等协调发展，才能推进制造业信息化。并且描述了一个建立在制造信息化基础上的未来智能工作场模型，其具有软硬件方面的快速可重构性，以知识的挖掘、应用、革新作为驱动制造、装备智能化和高效率工作的内在机制，能形成多个车间、工作场间信息的双向流通。     

基于彩色火焰图像的铝、硼纳米颗粒燃烧特性

用彩色数码相机拍照结合图像处理的诊断方法研究了铝、硼纳米颗粒的燃烧特性和机理,得到了铝、硼纳米颗粒火焰的形貌特征、温度分布及着火时间等。燃烧实验中使用多元扩散平焰燃烧器(Hencken燃烧器)提供可控的高温环境,利用固体颗粒乙醇溶解-超声分散-雾化-干燥的给粉方式产生高分散的纳米气溶胶,并在不同工况下对纳米颗粒火焰进行拍照。从所得彩色图片中提取红、绿、蓝三色通道信号,结合普朗克辐射定律获得颗粒的辐射强度信息及温度信息。结果表明:不同环境温度会导致不同的颗粒变温历程。高温环境下铝、硼颗粒经着火后颗粒温度逐渐下降,而低温下由于氧化层多晶相变的影响铝颗粒温度先缓慢升高而后缓慢下降,硼颗粒温度则几乎维持恒定。硼颗粒着火过程可分为着火延时和着火两个阶段,通过火焰图像定义了相应的时间,测得的硼颗粒着火延迟时间为1.17~2.98ms,着火时间为0.31~0.85ms。     

An experimental and mathematical study on the effects of ignition energy and system on the flame kernel development

A constant volume combustion chamber is used to investigate the flame kernel development of gasoline air mixtures under various ignition systems, ignition energies and spark plugs. Three kinds of ignition systems are designed and assembled, and the ignition energy is controlled by the variation of the dwell time. Several kinds of spark plugs are also tested. The velocity of flame propagation is measured by a laser deflection method, and the combustion pressure is analyzed by the heat release rate and the mass fraction burnt. The results represent that as the ignition energy is increased by enlarging either dwell time or spark plug gap, the heat release rate and the mass fraction burnt are increased. The electrodes materials and shapes influence the flame kernel development by changing he transfer efficiency of electrical energy to chemical energy. The diameter of electrodes also influences the heat release rate and the burnt mass fraction.     

基于量化指标的制造业信息化工程需求分析

提出了基于量化指标体系的制造业信息化工程需求分析评价理论，设计了制造业信息化工程需求分析评价指标体系，应用层次分析法进行指标量化和指标权重设计。按照制造业信息化工程分级规律，通过选择合理的模糊隶属函数，建立模糊关系矩阵，运用模糊评判获得制造业信息化工程需求分析评判值，依据评判值的大小判定企业对制造业信息化工程的需求水平。该研究旨在提供解决目前制造业信息化工程需求分析中的不规范、不确定性问题的思路和借鉴方法，有利于发现制约企业实施制造业信息化工程的瓶颈因素。     

现代CAPP技术及其发展研究

企业信息化工程推动了CAPP技术的发展和应用，本文通过CAPP的发展过程、信息技术的发展以及企业信息化工程对CAPP的需求等进行深入分析，从体系结构、系统功能、信息组织、工艺设计模式、系统性能等方面分析了现代CAPP技术的发展趋势。(1)CAPP系统的体系结构由单机模式、C／S模式向C／S模式与基于Web技术的B／S模式相结合、组件化、层次结构化方向发展；(2)CAPP系统的功能覆盖企业整个工艺领域，向集成化制造数据管理方向发展；(3)工艺设计模式向基于知识的分布协同决策的综合智能化设计技术发展；(4)CAPP的应用更加强调系统的集成性和开放性等。文中还简要介绍了相关关键技术。     

区域性制造业信息化工程方案设计方法研究

分析了区域性制造业信息化的资源系统构成及其市场要素需求，从资源优化配置角度，以支持区域制造业与信息化技术服务产业的整体发展为目的，构建了区域性整体制造业信息化工程的设计实施体系框架，并研究了其中的关键环节，提出了企业信息化的梯度扩展理论．在需求分析的基础上阐述了典型区域制造业信息化工程规划方案。     

Comparisons of predicted and measured results on performance and emission of engine effected by intake air dilution and supercharging

An experimental study was conducted on a single cylinder direct injection diesel engine to investigate the effects of diluting intake air, with different gases and increasing intake pressure on combustion process and exhaust emissions. The intake O₂ concentration is changed from 15% to 21% by diluting intake air with different gases (CO₂, Ar, N₂), and the intake pressure is changed from one to two bar by a screw compressor. A modified program for calculating heat release rate, is used to study the characteristics of combustion and exhaust emissions in detail. The main results show that the addition of either CO₂ or Ar to the intake air increases the ignition delay. The variations of ignition delay with CO₂ are much larger than those of ignition delay with Ar for the same O₂ concentration. The emission of NOx decreases with the decrease of O₂ concentration and the smoke level is lower with the addition of the CO₂ than with that of Ar. As the intake pressure is increased, the ignition delay is shortened. Furthermore the high intake air pressure enhances the air-fuel mixing and diffusion combustion, and reduces the premixed combustion, so that NOx emission is decreased without increasing smoke emissions. The addition of CO₂ at high intake pressure, drastically reduces NOx emissions and smoke emission simultaneously at a high load condition, and the addition of CO₂ reduces NOx emissions without affecting the smoke emissions substantially at a low load condition. A zero-dimensional combustion simulation program incorporated with the present heat release correlation and ignition delay correlation is used to predict ignition delay, cylinder pressure and engine power. The results show that the correlations are likely to be adequate for the engine operating under diluted intake air and various intake pressure.     

用于电弧发射光谱的数字化自动引弧电路设计

转盘电极发射光谱分析技术在油液成分检测中有重要应用,研究表明,电弧光源的稳定性对光谱分析的结果有重要影响,传统的电弧发生器多使用火花放电器作为引弧电路的核心器件,在油液成分分析中引弧的稳定性和可靠性难以保证.文章提出了一种用于电弧光源激发的数字化自动引弧电路,建立了高频引弧电路拓扑结构模型,使用双路可控硅代替火花放电器...     

Flow direction characteristics in the vicinity of the spark plug in an S. I. Engine

The flame speed may be decomposed into the burning speed and the flame transport speed. The flame transport speed is affected considerably by the flow direction, variation rate of flow direction, and flow speed in the combustion chamber. Especially, the flow direction and the variation rate of flow direction at the spark plug location during the ignition period have an important effect on the ignition process and the early flame propagation process. We measured the flow direction component and the variation rate of flow direction with a hot wire probe at the spark plug location. It was shown that the representative flow direction of ignition period is the right-vertical direction of crank shaft and it was used to investigate the variation rate of flow direction.     

某型燃油电控调节器结构改进设计研究

某型燃油电控调节器是用于某型发动机燃油数控系统的执行装置，在厂内调试时，空中起动点火供油量性能调试困难；在进行交付试验时出现了空中起动点火供油量变小，即性能不稳定的问题。针对上述不足，对该调节器的组成、功能、工作原理进行详细分析，从而对其压差回油装置进行结构改进设计及静差分析，利用AMESim仿真软件建立数学模型并给出性能仿真结果。改进后的试验结果表明，空中起动点火供油量指标已达到要求，保证了发动机的正常工作。     

面向区域中小企业的制造业信息化建设体系研究

为适应国家的制造业信息化工程,提出了根据区域发展情况开展区域制造业信息化建设模式,包括组织保障体系、政策保障体系、中介服务体系和技术攻关推广体系,并分别对各个体系建设给出了实施措施,为政府推进信息化进程提供指导。     

Characteristics of auto-ignition and micro-explosion behavior of a single droplet of water-in-fuel

The characteristics of auto-ignition and micro-explosion behaviors of a single fuel droplet have been investigated experimentally with varying droplet sizes, ambient temperature, and water content. The fuel used for this experiment was pure n-decane, which was emulsified with several water content varied from 10% to 30% to compare the effects of water content in the emulsified fuel. Imaging with a high-speed digital camera was adopted to measure the ignition delay and flame life-time, as well as to observe micro-explosion behavior. The increase of droplet size and furnace temperature causes a decrease of the ignition delay time. The flame life-time is augmented as the droplet size increases, however it doesn’t seem to be affected by the ambient temperature relatively. As the water content increases, the ignition delay increases and the micro-explosion behavior is strengthened. The start timings of micro-explosion and fuel puffing are compared for different droplet sizes and the amount of water content.     

Physical characteristics of welding arc ignition process

The existing research of welding arc mainly focuses on the stable combustion state and the research on the mechanism of welding arc ignition process is quite lack.The tungsten inert gas(TIG) touch arc ignition process is observed via a high speed camera and the high time resolution spectral diagnosis system.The changing phenomenon of main ionized element provided the electrons in the arc ignition is found.The metallic element is the main contributor to provide the electrons at the beginning of the discharging,and then the excitated shielding gas element replaces the function of the metallic element.The electron density during the period of the arc ignition is calculated by the Stark-broadened lines of Hα.Through the discussion with the repeatability in relaxation phenomenon,the statistical regularity in the arc ignition process is analyzed.The similar rules as above are observed through the comparison with the laser-assisted arc ignition experiments and the metal inert gas(MIG) arc ignition experiments.This research is helpful to further understanding on the generation mechanism of welding arc ignition and also has a certain academic and practical significance on enriching the welding physical theoretical foundation and improving the precise monitoring on automatic arc welding process.     

火花塞电磁兼容性能的提升对策

近年来,乘用车辆采用了越来越多的电子设备,需要系统考虑车辆上所有电器件的电磁兼容性能;同时发动机技术的提升也对电磁兼容性能提出了更高的要求。火花塞作为发动机点火系列中的点火执行器,其单体不具备辐射电磁波的能力。但火花塞点火时,释放点火线圈储存的能量,在间隙击穿的瞬间,其周围的电场会发生急剧变化,从而产生电磁波。可以通过减小间隙、使用贵金属尖端中心电极等手段,降低点火电压,从而降低电磁波的频率和能量;同时采用合适的包边口尺寸和合适的接线端子位置,采用屏蔽型等手段,来减短和缩小电磁波传播的路径,达到良好的火花塞电磁兼容性能。采用电阻型、电感型、磁阻型的火花塞结构是抑制电磁波常用和主要的手段,通过不同的组合可以实现更好的火花塞电磁兼容性能。     

微晶体共沉淀点火药其电感度的改性研究

本文研究了微晶体共沉淀点火药应用于刚性电引火药头,其点火性能和电感度。刚性电引火药头以LDNP为内层点火药,微晶体共沉淀点火药为外层点火药的燃烧性能和点火能力。实验表明,用LDNP为内层点火药,以粉碎后的微晶体共沉淀点火药为外层点火药,可改善引火药头的电感度。发火火焰好,有很好的点火能力和一致性。     

基于激光点火系统装置的论述与分析

激光点火作为一种技术,经实验已广泛应用于多个领域,尤其在许多武器发射技术中,激光点火技术是对常规底部底火点火方式的革新。文中分别介绍了激光单点点火、双点点火和多点点火的组成结构和不同的功能,阐明激光了点火技术装置的原理和组成结构。     

Effects of equivalence ratio and carbon dioxide concentration on premixed charge compression ignition of gasoline and diesel-like fuel blends

The effects of fuel/air equivalence ratio and CO₂ concentration in fuel/air charge on the ignition process of gasoline and diesel-like fuel (n-heptane) blends on a rapid compression machine are investigated in this study. Results showed that the effects of equivalence ratio on ignition delays of two ignition stages are varied. As equivalence ratio increases from 0.3 to 0.5, the first stage ignition delay slightly increases because the increased equivalence ratio improves the mixture heat capacity, reducing the in-cylinder temperature and weakening the low-temperature heat release process of the fuel. The second stage ignition delay is shortened with the increased equivalence ratio because increased fuel concentration facilitates mixture reactivity. CO₂ addition to the cylinder charge can effectively reduce the peak cylinder pressure and the two stage pressure rise rates, as well as extend the durations of ignition delays of two ignition stages.     

An experiment of the combustion characteristics with laser-induced spark ignition

The combustion characteristics and minimum ignition energies using laser-induced spark ignition were demonstrated for quiescent methane-air mixtures in an optically-accessible, constant volume combustion chamber. Initial pressure and equivalence ratio as well as spark energy were varied in order to explore the flame behavior with laser-induced spark ignition. Shadowgraphs for the early stages of combustion process showed that the flame kernel becomes separated into two, one of which grows back towards the laser source. Eventually after a short period, the two flame kernels developed into two flame fronts propagating individually, which is unique in laser-induced spark ignition. For a given mixture, lower initial mixture pressure and higher spark energy resulted in shorter flame initiation period and faster flame propagation. The results of minimum ignition energies for laser ignition shows higher values than electric discharge results, however, the difference decreases toward lean and rich flammability limits.     

等离子体对碳氢燃料点火延迟时间影响的研究进展

应用等离子体减小碳氢燃料点火延迟时间的优越性已经越来越明显。论文总结了点火延迟时间的主要定义和表达方式,分析了等离子体影响碳氢燃料点火过程的重要机理、简化模型以及主要的实验装置,并列举了前面研究者利用等离子体影响碳氢燃料点火延迟时间的实验研究,最后提出了高压纳秒脉冲放电等离子体的应用前景广阔。