气体爆燃向爆轰转捩的理论分析（增刊）

本文在实验的基础上,对瓦斯爆炸过程中爆燃向爆轰转捩(DDT, Deflagration to Detonation Transition)问题进行了研究,并运用CJ(Chapman and Jouguet)理论计算了火焰阵面流场参数。研究结果表明：障碍物对瓦斯爆炸过程中爆燃向爆轰转捩具有诱导作用,无障碍物时爆炸波的传播速度较小,爆炸强度较弱;随着障碍物的增多,爆炸波和火焰传播速度明显增大,爆燃易于向爆轰转捩,爆炸强度和危险性显著提高。上述研究结果对于现场如何防治瓦斯爆炸,防止、降低煤矿重大事故的发生具有一定的指导作用。     

气体爆燃向爆轰转捩的实验研究

在实验的基础上,对瓦斯爆炸过程中爆燃转变为爆轰(DDT,Deflagration To Detonation)问题进行了研究。研究结果表明:障碍物对瓦斯爆炸过程中爆燃向爆轰转捩有诱导作用。无障碍物时,随着爆燃波阵面传播距离的增加,其阵面压力增长缓慢,并且不出现爆炸波的突变界面,不易转变为爆轰波;障碍物增多时,爆燃波阵面压力增长较大,其传播速度能超过音速,并有压力尖峰,从而容易形成爆轰波;当爆燃转变为爆轰时,峰值超压则显著提高。研究结果对于现场如何防治瓦斯爆炸,减轻瓦斯爆炸灾害具有一定作用。     

瓦斯爆炸动力学特征参数的测定及其分析

在实验的基础上，研究了瓦斯爆炸过程中的动力学特征参数及其影响作用，其中主要包括火焰与超压、火焰与爆炸波之间的相互关系，障碍物对火焰、爆炸波传播的影响。研究结果表明，瓦斯在爆炸的过程中，超压与火焰的速度有关，爆炸波在火焰前言，其传播速度明显高于火焰，爆炸波与火焰之间的时间差不仅和位置有关，而且还和障碍物的数量有关。障碍物对爆炸波和火焰的传播具有加速作用，爆炸波和火焰传播规律可表示为T＝mL/D＋b，回归所得到的相关系数r＞0.9，回归曲的结果是显著的。随着障碍物的增多，火焰和爆炸波传播规律的线性度降低，非线性度增大。研究结果对指导现场如何防治瓦斯爆炸，减轻瓦斯爆炸的威力具有重要作用。     

瓦斯爆炸在分岔管道中的传播规律及分析

为了探索瓦斯爆炸在分岔管道中的传播规律,通过实验测定了瓦斯爆炸在分岔管道中传播的爆炸波超压值和火焰传播速度,并对瓦斯爆炸在分岔管道中的传播进行了理论分析.研究结果表明,管道分岔对瓦斯爆炸的火焰和超压都有增强的作用,火焰和爆炸波对分岔处管壁的破坏特别大.因此在矿井巷道开拓设计时,应尽量避免巷道分岔,同时避免巷道内障碍物的堆积.在必须分岔时,应根据分岔巷道瓦斯爆炸传播规律来采取相应的预防措施,以阻止瓦斯爆炸的传播和降低强度,减少瓦斯爆炸带来的损失.     

电磁场对瓦斯爆炸过程中火焰和爆炸波的影响

在实验的基础上,研究了电磁场对瓦斯爆炸过程中火焰传播和爆炸波的影响.研究结果表明：电磁场对瓦斯爆炸过程影响非常明显,加电磁场后瓦斯爆炸火焰传播速度和爆炸波超压均比光滑管道有大幅提高,而且随着电磁场强度的增加,影响程度加强.基于电磁场对瓦斯爆炸传播特性的实验结论,从理论上分析了电磁场对瓦斯爆炸的影响机理,并对实验现象做出了合理的解释.但是由于电场与磁场在瓦斯爆炸过程中的互相制约,电磁场效应不是磁场效应和电场效应简单的相互加剧关系.     

瓦斯爆炸过程中火焰传播规律及其加速机理的研究

在实验的基础上,研究了瓦斯爆炸过程中火焰传播规律及其加速机理．研究结果表明,障碍物对瓦斯爆炸过程中火焰传播规律具有重要影响．当有障碍物存在时,瓦斯爆炸过程中火焰的传播速度将迅速提高．在沿火焰传播的通道上设置障碍物,对气相火焰具有加速作用,这种加速作用的机理可归功于障碍物诱导的湍流区对燃烧过程的正反馈．     

瓦斯爆炸过程中爆炸波传播特征的实验研究

本文在实际的基础上,测定了瓦斯爆炸过程中爆炸波的特征参数,并计算了爆炸过程的超压及比冲量。研究结果表明：障碍物对瓦斯爆炸过程中的冲击波具有诱导作用,产生冲击波时,其阵面峰值超压软大,具有很强的破坏作用。研究结果对于现场防治瓦斯爆炸具有一定意义。     

爆炸波能量变化特征及壁面热效应

在研究爆炸波能量变化特征的基础上，采用实验方法研究了壁面热效应对瓦斯爆炸传播特性的影响．研究结果表明：瓦斯爆炸释热可分为4部分：①通过对流、热辐射变成了壁面散热；②通过导热、扩散和热辐射传给未燃气体；③通过膨胀做功变成了爆炸波能量及产物动能；④传播过程中的各项损失．管道内贴绝热材料后，壁面散热大幅减小(约为原来的1／3)．减少的热量一部分通过导热、扩散向未燃气体传递．另一部分通过膨胀做功使爆炸波强度增大．两者均使火焰燃烧传播速度、爆炸波强度增加，并可诱导激波的产生．     

障碍物对巷道瓦斯爆炸传播影响数值模拟研究

采用流体力学软件FLUENT对不同障碍物情况下巷遭瓦斯爆炸过程进行数值模拟,研究了障碍物对爆炸传播的影响。模拟结果清晰地显示了巷道瓦斯爆炸火焰传播过程,并且表明巷道障碍物的存在会产生湍流现象加速火焰传播,增大瓦斯爆炸的危害,因此巷道中应尽量减少不必要的障碍物存在。     

障碍物和阻塞比对瓦斯爆炸影响的数值模拟

瓦斯爆炸是煤矿开采过程中时有发生的严重事故,研究表明障碍物对瓦斯爆炸传播有很大影响。采用数值模拟的手段分析研究了障碍物的个数和阻塞比对瓦斯爆炸的影响。首先建立瓦斯爆炸数值计算模型,并参照试验数据,验证采用模型的正确性。采用该模型对不同阻塞比和不同障碍物个数对瓦斯爆炸的影响进行对比分析,分析这些因素对瓦斯爆炸火焰、压力和温度产生的影响。研究结果认为障碍物的存在增大火焰传播速度,并且障碍物的个数和阻塞比的大小对火焰传播速度有很大影响。     

Market and recycling of NiMH battery

<正>Market status and future trend of NiMH battery1.Global market of small NiMH battery Global market size of small NiMH batteries declined year on year since 2011.The trend will continue to 2018,at the rate of 5%to 10%annually.Demand for small NiMH batteries will be stable gradually.Many electrical apparatuses are powered by the built-in lithium battery today,which is the main reason for the shrunk market of small NiMH batteries.But,for some products,small NiMH     

China rare earth market review

正September 1-10,2014 Affected by the National Day holiday,rare earth transaction was stagnant and the market showed a weak steady state.As there was no good news for downstream market,some products with flat demand would likely rally slightly for some time to     

Current situation and future trend of China rare earth luminescent material industry

<正>Rare earth luminescent material is one of the most important application sectors of rare earths.China enjoys the exceptional advantage to develop rare earth luminescent material for its abundant rare earth resources.After several decades'endeavor,China's rare earth luminescent material industry,headed by rare earth phosphor for lamp and LED and high efficient rare earth energy-saving light source,has been gradually developed into a scale industry.China has become a major production base of rare earth phosphor for lamps and rare earth     

China rare earth market review

正June 1~10,2014Rare earth market remained weak.Quoted price of rare earth products was similar to that in May.There was no sign of recovery in downstream market.The market of NdFeB magnetic materials and phosphor was depressed.Catalyst,polishing powder and ceramic industries remained inactive.Demand from downstream industry was soft.Consumers purchased on their needs.Suppliers had strong intention to sell.Prices of rare earth products     

2014 second batch of rare earth quota released

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Annual Report analysis of Chinese rare earth-related listed companies in 2013

<正>Chinese rare earth-related listed companies have published their 2013 annual reports.It can be understood from their reports that production and operation activities of Chinese rare earth-related companies were still heavily affected by macro economy and industrial policies.They basically followed the steps of national economy.In 2013,world economy recovered slowly but the economy     

Market opportunities and challenges for rare earth polishing powder

正1.Status of rare earth polishing powder Rare earth polishing powder with high content of cerium oxide began to replace iron oxide for glass polishing and became one of the key materials in glass polishing process since 1940.Compared with traditional iron oxide,rare earth polishing powder has many advantages,such as fast polishing rate,high polishing quality and long service life.It can achieve good surface quality and improve operation conditions.For example,in lens polishing,the polishing work that cerium     

Baotou Research Institute of Rare Earths developed a new RE alloy preparation technology

正Pyrometallurgy Laboratory of Baotou Research Institute of Rare Earths had independently developed a new preparation technology of rare earth alloy for NdFeB.The alloy can remarkably enhance the coercivity of NdFeB magnet but also evidently reduce the production cost of the magnet.The new master alloy was prepared in the kA pilot-scale electrolytic cell by the independent technology.The rare earth master alloy can be used as the raw material for NdFeB.Compared     

China rare earth market review

正November 21~30,2014Due to weak demand from downstream industries,transactions of rare earth in Chinese domestic market were inactive.It was difficult to sell any rare earth products except for dysprosium oxide and terbium oxide.Suppliers lost confidence in recent market.Demand for rare earth products was soft.Consumers continued to take a wait-and-see attitude.Rare earth export market remained slow.     

Galaxy Magnets achieved the net profit of 34.02 million yuan in the first six months of 2014

正Galaxy Magnet announced its financial results for the first half of 2014 on August 14.For the first six months ended on 30 June 2014,Galaxy Magnet achieved operation income of RMB 182.3 million,up8.40% over the same period of 2013,and the net profit attributable to the shareholders of the listed company of 34.02 million yuan,increasing 35.49% over the same period of last year.Stable performance increase was led by development of new customers and application market of magnets.