氢气/空气非预混旋转爆轰波形成与传播特性

针对非预混旋转爆轰波的形成与传播问题,本文通过三维数值模拟分析了氢气与空气的冷态掺混特性、爆轰波传播模态的演变规律和结构特点及其对进气过程的影响.计算结果表明:由于回流区的存在,燃料与氧化剂能够快速掺混均匀,在燃烧室进口附近,内壁面的当量比大于外壁面.透射激波多次对撞后最终形成一道压力较高的激波.爆轰波的传播方向与透射...     

正癸烷/空气旋转爆轰波形成与传播数值模拟

针对气液两相旋转爆轰波形成与传播问题,本文以液态正癸烷为燃料,采用欧拉-拉格朗日方法,通过三维数值模拟给出了两相旋转爆轰波的形成演变特点和自持传播机理。研究结果表明：在起爆阶段,通过调控初始燃料分布能够获得强度不同的爆轰波和压力波;在对撞阶段,爆轰波与压力波共发生4次对撞,由于缺乏燃料供给,压力波逐渐衰减并消失,爆轰波以单波模态传播;在稳定传播阶段,未燃燃料在三叉点处聚集形成未反应气流区并诱导产生局部爆炸。未反应气流区的周期性出现和局部爆炸是两相爆轰波自持传播的重要影响因素。     

爆轰波进入不可燃突扩管道行为研究

对爆轰波进入不可燃突扩管道后的传播规律及压力分布进行实验研究、数值模拟和理论分析.实验结果显示,爆轰波进入突扩管道一定距离后管道内压力会突升,随后压力曲线趋于平缓,在靠近封闭端面附近的压力又再次升高.采用自适应有限体积程序结合基元化学反应模型对流场进行了数值模拟.结果表明,爆轰波进入不可燃突扩管道后,化学反应停止,爆轰波衰减为激波.由于管道横截面的突然增大,激波在扩张段入口处发生绕射,平面波阵面逐渐演变为球面波阵面.该球面波阵面在向前传播的过程中与空腔上壁面先后发生规则反射和马赫反射.在发生马赫反射的位置,激波波后压力急剧升高.随马赫杆渐增,球面波阵面逐渐被抹平,最终再次形成平面激波.该平面激波到达封闭端面后又将发生反射,造成靠近封闭端面处的压力上升.     

一维CE/SE方法在气液两相爆轰计算中的应用

应用CE/SE方法对气液两相爆轰进行数值求解,研究了爆轰波在管内的传播过程.对刚性源相,采用四阶龙格库塔法对其求解.分析了液滴半径大小对爆轰波峰值压力的影响,液滴半径增大,爆轰压力减小,形成稳定爆轰波的距离增加;且液滴半径过大不能形成稳定的爆轰波.     

受限空间瓦斯爆炸火焰与毒气传播研究

为揭示瓦斯爆炸过程中火焰、毒气及压力三者间相互关系,采用一端封闭的爆炸试验装置,通过改变瓦斯聚集长度和点火强度,研究了瓦斯爆轰及爆燃状态下火焰、毒气及压力传播变化规律.结果表明,管道内瓦斯爆燃状态下火焰的传播速度远小于爆轰状态下的传播速度,变化趋势呈线性;瓦斯爆炸火焰传播速度的大小直接影响爆轰的形成以及爆炸强度和爆炸传播距离;爆燃状态下火焰和毒气传播的距离基本相当,均为原始瓦斯聚集总长度的2倍左右;爆轰状态下火焰和毒气传播的距离基本相当,均大于原始瓦斯聚集长度,但传播距离不确定.     

基于Rayleigh波的薄壁容器温度与压力测量方法

为了提高薄壁容器抗压能力,保证薄壁容器的安全运行,提出了一种压力与表面温度的非侵入式测量方法.基于Rayleigh波传播速度与传播介质的应力、温度有关这一原理,通过理论推导和实验研究,建立了Rayleigh波传播时间与容器表面温度、容器压力之间的实用模型.基于这一模型,通过测量Rayleigh波沿容器壁面轴向和切向固定距离上的传播时间可以同时测量容器的表面温度和内部压力.实验结果表明,这种表面温度测量方法响应速度快,且对被测表面温度场影响小;测量压力时不需要在容器上开孔,实现了无损测量,提高了压力容器的安全性.     

基岩保护层一次性爆破开挖技术分析研究

根据气体等熵膨胀理论、应力波传播理论和格里菲斯强度准则 ,推导了孔底压力和基岩破裂深度的计算公式 ,提出了孔底设柔性垫层对延缓爆轰作用的理论分析方法 ,并进行了工程实际验证 ,其计算结果与现场实测比较吻合     

基岩保护层一次性爆破开挖技术分析研究

根据气体等熵膨胀理论、应力波传播理论和格里菲斯强度准则，推导了孔底压力和基岩破裂深度的计算公式，提出了孔底设柔性垫层对延缓爆轰作用的理论分析方法，并进行了工程实际验证，其计算结果与现场实测比较吻合。     

用电阻应变传感器测定柱状药包爆轰压力的近似值

柱状药包置于一个盛满水的小薄壁圆柱筒的中央进行爆炸，药包中传播的爆轰波与水相互作用，在水中产生爆炸应力波，应力波从水中透射到圆筒，使得圆筒产生环向变形；用超动态应变测试系统测定圆筒外壁上的环向爆炸应变波，根据应变波的峰值与爆轰压力之间的关系，可以确定柱状中空药包爆轰压力的近似值，本文介绍了测试方法及测定结果。     

非线性电路中的孤子

给出产生孤子的电路单元结构,通过对理想非线性电路的数值仿真分析,得出孤子随时间传播变化的情况,以及激励幅值与孤子传播速度的关系。通过实验验证孤子传播现象,实验结果与仿真结果定性一致。     

Propagating Characteristic of Premixed Methane-Oxygen Deflagration in the Coal Mine Lane Including a Refuge Chamber

In order to investigate detonation propagation and distribution problems of premixed CH4+2O2 mixture around a concrete structure such as a refuge chamber,detonation experiments in one small size tube were conducted.A simulation method was developed to obtain the flow field load distribution in the coal mine lane and pressure load of each part for the refuge chamber.Firstly,a physical model of a full-size explosion-test lane was established,which included the refuge chamber.With the calculations of the exact initial detonation pressure,the propagation characteristics of CH4+2O2 premixed mixture detonation in the lane was simulated.Simulation results of various parts from AUTODYN are recorded,and the shock wave arrival time and the pressure peak can be observed from the detonation pressure-time curve over the changing propagation distance.So curve differences in different locations cannot be ignored.Then by detonation experiments in the small size tube,detonation pressure-time curves and velocity were obtained.Finally the simulation waveform of variation curve agreed well with the experimental results,which validated the detonation simulation method.The difference between shockwaves of the two sensors confirmed that detonation wave changed along with distance and time.These results should be taken into serious consideration for the detonation progration and distribution problem in future researches.     

Propagating Characteristic of Premixed Methane-Oxygen Deflagration in the Coal Mine Lane Including a Refuge Chamber

In order to investigate detonation propagation and distribution problems of premixed CH4 + 2O2 mixture around a concrete structure such as a refuge chamber,detonation experiments in one small size tube were conducted.A simulation method was developed to obtain the flow field load distribution in the coal mine lane and pressure load of each part for the refuge chamber.Firstly,a physical model of a full-size explosion-test lane was established,which included the refuge chamber.With the calculations of the exact initial detonation pressure,the propagation characteristics of CH4 + 2O2 premixed mixture detonation in the lane was simulated.Simulation results of various parts from AUTODYN are recorded,and the shock wave arrival time and the pressure peak can be observed from the detonation pressure-time curve over the changing propagation distance.So curve differences in different locations cannot be ignored.Then by detonation experiments in the small size tube,detonation pressure-time curves and velocity were obtained.Finally the simulation waveform of variation curve agreed well with the experimental results,which validated the detonation simulation method.The difference between shockwaves of the two sensors confirmed that detonation wave changed along with distance and time.These results should be taken into serious consideration for the detonation progration and distribution problem in future researches.     

输气管线中减压波传播特性模拟及分析

结合相平衡计算模型、声速计算模型和气体流出速度模型等建立了输气管线中减压波波速预测模型。采用该模型分析研究了气质、初始温度、初始压力对减压波特性的影响,以及计算时选择不同的状态方程对预测结果的影响等。结果表明,重组分含量较大的组分在破裂过程中容易进入气液两相区,减压波曲线出现“平台”,较低的初始温度和较高的初始压力相对增大了裂纹扩展的风险,在计算过程中,需要选择合适的状态方程。     

混合气体燃烧中压力对爆震波特性参数影响研究

采用平衡常数法对烃一空气混合气体燃烧中爆震燃烧产物的平衡温度、平衡压力及爆震波速进行了计算与分析。在此基础上研究了混合气压力对爆震波特性参数的影响。研究结果表明：在同一混气余气系数下，平衡温度和爆震波速随混气压力的增大而增大，而平衡压力则随混气压力呈线性增大。同时，对于不同燃料，分子量越大，其平衡温度、平衡压力就越高。     

尿素合成塔爆炸事故的数值模拟研究

针对尿素合成塔爆炸事故及过程分析,采用数值方法对尿素合成塔塔顶部的气相空间爆炸进行模拟,找出冲击波形成、传播规律、强度和进入液相传播的时间差;综合模拟冲击波进入液相传播的时间差和传播速度,计算得到冲击波在液相中位于尿素塔底部的叠加点位置及对应的冲击波叠加压力。结果表明,叠加后冲击波的压力显著增加,其强度足以造成该处筒体破坏,过热液体瞬间气化喷出,从而引发破坏更大的二次爆炸。     

Detonation Propagation Characteristics of Superposition Explosive Materials

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Propagation law of shock waves and gas flow in cross roadway caused by coal and gas outburst

In order to study the propagation law of shock waves and gas flow during coal and gas outburst, we analyzed the formation process of outburst shock waves and gas flow and established the numerical simulation models of the roadways with 45° intersection and 135° intersection to simulate the propagation of outburst gas flow and the process of gas transport. Based on the analysis of the simulation results, we obtained the qualitative and quantitative conclusions on the characteristics and patterns of propagation and attenuation of outburst shock waves and gas flow. With the experimental models, we investigated the outburst shock waves and gas flow in the roadways with the similar structures to the simulated ones. According to the simulation results, when the angle between the driving roadway and the adjacent roadway increased, the sudden pressure variation range in adjacent roadway and the influencing scope of gas flow increased and the sudden pressure variation duration decreased. The intersection between the driving roadway and the adjacent roadway has no effect on airflow reversal induced by the shock waves and gas flow.     

低温等离子体点火乙炔／空气爆震特性试验

为研究交流驱动低温等离子体点火触发爆震特性,在长1.5 m、内径60 mm的爆震管上,以乙炔为燃料,空气为氧化剂,按分压法配气,通过循环,使爆震管内混气混合均匀,进行气相单次爆震实验.采用交流驱动低温等离子体点火,单次放电时间0.5 ms,放电能量约为0.2 J.在点火的同时,用压力传感器和离子探针同时采集爆震管内的压力波和火焰传播特性.实验表明:交流驱动低温等离子体实现了乙炔/空气点火起爆过程,余气系数0.6及1.0混气产生很强的爆震波,余气系数下降,混气压力下降,爆震波传播速度和峰值压力下降,DDT距离和时间增加;余气系数1.4混气不能产生爆震波.     

Influence of obstacle-produced turbulence on development of premixed flames

An investigation into influence of obstructions on premixed flame propagation has been carried out in a semi-open tube. It is found that there exists flame acceleration and rising overpressure along the path of flame due to obstacles. According to the magnitude of flame speeds, the propagation of flame in the tube can be classified into three regimes: the quenching, the choking and the detonation regimes. In premixed flames near the flammability limits, the flame is observed first to accelerate and then to quench itself after propagating past a certain number of obstacles. In the choking regime, the maximum flame speeds are somewhat below the combustion product sound speeds, and insensitive to the blockage ratio. In the more sensitive mixtures, the transition to detonation (DDT) occurs when the equivalence ratio increases. The transition is not observed for the less sensitive mixtures. The dependence of overpressure on blockage ratio is not monotonous. Furthermore, a numerical study of flame acceleration