ABC 干粉对爆燃火焰传播抑制的实验

为了研究ABC干粉的抑爆效能,利用自行研制的抑爆实验装置对ABC超细干粉和磷酸二氢铵质量分数分别为90％、75％、50％的ABC干粉进行抑爆实验,通过对火焰传播速度抑制效果的比对,研究不同类型ABC干粉和磷酸二氢铵质量分数对粉剂抑爆效能的影响。结果表明：ABC干粉作为抑制爆燃火焰传播的介质,能够对火焰起到持续的消焰作用,减缓火焰传播速度,有效控制爆燃向爆轰的发展;ABC干粉的粒径和磷酸二氢铵质量分数不同,对爆燃火焰传播速度的抑制能力存在差别;同等磷酸二氢铵质量分数的ABC干粉,粒径越小、均匀程度越好,抑制火焰速度的效果越好;同等粒度的ABC干粉,磷酸二氢铵质量分数越高,抑制火焰速度的效果越好;减小ABC干粉的粒径和增加磷酸二氢铵的质量分数都可以提升抑爆效能,通过增加ABC干粉的磷酸二氢铵质量分数可以在一定程度上弥补粉剂粒径和均匀度上的不足。     

ABC干粉对爆燃火焰传播抑制实验

为了研究ABC干粉的抑爆效能,利用自行研制的抑爆实验装置对ABC超细干粉和磷酸二氢铵质量分数分别为90％、75％ 、50％的ABC干粉进行抑爆实验,通过对火焰传播速度抑制效果的比对,研究不同类型ABC干粉和磷酸二氢铵质量分数对粉剂抑爆效能的影响.研究结果表明,ABC干粉作为抑制爆燃火焰传播的介质,能够对火焰起到持续的消焰作用,减缓火焰传播速度,有效控制爆燃向爆轰的发展;ABC干粉的粒径和磷酸二氢铵质量分数不同,对爆燃火焰传播速度的抑制能力存在差别;同等磷酸二氢铵质量分数的ABC干粉,粒径越小、均匀程度越好,抑制火焰速度的效果越好;同等粒度的ABC干粉,磷酸二氢铵质量分数越高,抑制火焰速度的效果越好;减小ABC干粉的粒径和增加磷酸二氢铵的质量分数都可以提升抑爆效能,通过增加ABC干粉的磷酸二氢铵质重分数可以在一定程度上弥补粉剂粒径和均匀度上的不足.     

瓦斯煤尘爆炸巷道反射压力研究

为揭示瓦斯和瓦斯煤尘爆炸反射压力沿矿井巷道传播变化的规律,用管道爆炸实验系统模拟测试极弱爆炸和极强爆炸巷道超压与反射压力的定量变化关系.结果表明,瓦斯和瓦斯煤尘与空气混合爆炸,在弱爆炸条件下爆炸的反射压力均是峰值超压的1.8~2.0倍,強爆炸下瓦斯或瓦斯煤尘爆炸的反射压力大约是峰值超压的8~21倍.实验结果与理论计算基本吻合,表明巷道反射压力强度取决于冲击波在巷道空间内的反射过程,巷道内爆炸超压强度随爆炸传播距离的增加而降低,遇固壁则反射压力强度加大,加重了井下设备的破坏和人员伤害程度.     

Analysis of vacuum chamber suppressing gas explosion

In order to suppress the harm of gas explosion, the current study researched on the body of vacuum chamber. The previous studies verified that it could obviously lower the explosion overpressure by reasonably arranging vacuum chamber on pipe. That is to say, the vacuum chamber has the effect of absorbing wave and energy. To further deeply analyze the vacuum chamber suppressing gas explosion, this research designed the L-type pipe of gas explosion, and compared the experimental results of gas explosion with vacuum chamber and without vacuum chamber. Besides, using the gas chromatograph, this study also investigated the gas compositions in the pipe before and after explosion. The results show that: (1) without vacuum chamber, the maximum value of explosion overpressure is 0.22 MPa, with 60 ms duration, and after explosion, the concentration of oxygen drops to 12.07%, but the concentration of carbon monoxide increases to 4392.3 × 10^?6, and the concentration of carbon dioxide goes up to 7.848%, which can make the persons in danger suffocate and die; (2) with vacuum chamber, explosion overpressure drops to 0.18 MPa, with 20 ms duration or less, and after explosion, the concentration of oxygen still remains 12.07%, but the concentration of methane is 7.83%, however the concentration of carbon monoxide is only 727.24 × 10^?6, and the concentration of carbon dioxide is only 1.219%, at the this moment the concentration ratio of toxic gas drops by more than 83% in comparison to be that without vacuum chamber. Consequently, the vacuum chamber can guarantee that most methane does not take part in chemical reaction, and timely quenches the deflagration reaction of gas and oxygen. Because of the two points mentioned above, it reduces the explosion energy, and lowers that the overpressure of blast wave impacts and damages on the persons and facilities, and also decreases the consumption of oxygen and the production of the toxic gas. Therefore, it is safe to conclude that the vacuum chamber not only absorbs wave and energy, but also prevents and suppresses explosion.     

KTB氧枪位置对RH真空室气体流动的影响

通过建立RH真空精炼过程中真空室内气体流动场数学模型，模拟研究了供氧顶枪位置对真空室内气体流动场的影响，为认识顶枪在真空精炼中的作用和顶枪的操作控制奠定了理论基础。     

一种FGZ-10型灌装机的设计与研制

介绍了一种FGZ-10型负压灌装机的设计与研制方法.该设备是在广泛吸收国内外先进机型的基础上研制开发的系列产品,是药液负压灌装自动生产线的关健设备.现场使用结果表明,该灌装机使用方便,具有速度可调、计量准确、运行平稳、无噪音和药液不外溢等优点,达到预期设计目标.     

微机控制弹性压力系统的研究

研制了一种野战电脑气压止血仪，属于弹性气囊压力控制系统在医学领域中的应用，它是对野战急救设备进行更新换代的改型要求，在对该系统研究中，应用PIC单片机控制技术，选用Motorola硅MPX100新型传感器，进行了硬件和软件的设计。     

金属丝状材料对预混气体爆炸影响规律研究

在自主设计加工的气体爆炸瞬态压力实验装置中,填充Cu、Al、Ni、Fe金属丝状材料后分别进行甲烷-空气(体积比为12%)和丙烷-空气(体积比为8%)预混气体的密闭爆炸实验,测定爆炸瞬态压力变化情况并进行对比分析。研究结果表明:填充金属丝状材料后爆炸压力峰值明显减小,说明能够有效地抑制可燃气体的爆炸;不同金属丝状材料的抑爆效果有明显的差异,其中Ni、Fe金属丝状材料抑爆性能明显优于Cu、Al金属丝状材料;随着可燃气体的分子质量的增加,Ni、Fe金属丝状材料抑爆性能优于Al、Cu金属丝状材料抑爆性能的现象更加明显。     

凝汽器真空严密性研究

本文建立了凝汽器在真空严密性试验工况时排汔压力的动态数学模型，分析了凝汽器真空下降速度与漏入空气量之间的关系，并对真空严密性试验的工作程序提出了修改意见。     

Effect of variation in gas distribution on explosion propagation characteristics in coal mines

In order to investigate the effect of variation in the distribution of gas on explosion propagation characteristics in coal mines, experiments were carried out in two different channels with variation in gas concentration and geometry. Flame and pressure transducers were used to track the explosion front velocity. The flame speed (Sf) showed a slight downward trend while the methane concentration varied from 10% to 3% in the experimental channel. The peak overpressure (Pmax) dropped dramatically when com-pared with normal conditions. As well, the values of Pmax and Sf decreased when the methane concentration dropped from 8% to 6%. The flame speed in the channel, connected to a cylinder with a length varying from 0.5 to 2 m, was greater than that in the normal channel. The peak overpressure was also higher than that under normal conditions because of a higher flame speed and stronger pressure piling up. The values of Pmax and Sf increased with an increase in cylinder length. The research results indicate that damage caused by explosions can be reduced by decreasing the gas concentration, which should be immediately detected in roadways with large cross-sections because of the possibility of greater destruction caused by more serious explosions.     

液冷系统中均热板气液相变的热质传输模拟

为提高电池热管理液冷系统的均温性,研究一种铝槽式均热板和直流式液冷板相结合的复合液冷系统,并建立相应的三维传热模型。采用Volume-of-fluid(VOF)多相流模型,模拟均热板槽道内丙酮工质的气液相变过程,以及与液冷流道的耦合传热过程,并将模拟结果与实验结果进行了对比,验证了模型的正确性。研究结果显示,均热板可以提高液冷系统散热过程中的均温性,加热表面的温差可以控制在2.72 K以内。通过机理分析发现,其原因与均热板内部气液工质的热质传输过程有关。在液冷系统冷却液沿程温升的影响下,均热板腔室中的丙酮气相工质在长度方向上存在定向输运现象,相变产生的蒸汽会携带热量从高温区往低温区流动,从而抑制液冷板低温冷却水对加热表面温度分布的影响,提高了均温性能。     

Cr12MoV钢真空油淬工艺研究

利用金相显微镜、扫描电镜、X射线衍射仪研究了Cr12MoV钢不同淬火工艺处理后的组织,并通过显微硬度计和磨损试验机测定了样品的显微硬度和耐磨性。结果表明,Cr12MoV钢真空油淬处理后,其组织主要由马氏体、碳化物和残余奥氏体组成。冷处理使残余奥氏体量下降,样品的硬度及耐磨性显著提高。     

离心泵泵腔内压力分布的实验研究

将泵腔内的液体流动简化为理想液体，利用Navier-Stokes方程建立了泵腔内压力的计算方程式，并应用离心泵欧拉方程式求解泵腔内压力计算方程式.通过对实验值与理论计算值的比较，得出了一些有益的结论：靠近密封环处，计算结果先小于实测值，后大于实测值；在外径处计算结果一直大于实测值；在大流量时计算结果和实测值几乎平衡.     

真空压差法在制动总泵缸体缺陷检测中的应用

介绍了真空压差法的测试原理及在汽车制动总泵缸体缺陷检测中的应用;分析了由于制动总泵缸体在制造过程中产生的不同缺陷所形成的3种不同密封泄漏曲线,根据曲线的形状和泄漏值的大小可以很清楚地判断出缺陷的类型、大小及在缺体上所处的位置;讨论了为保证测试数据的准确性应用真空压差法时应注意的几个关键问题.采用真空压差法的试验台用于在线检测,准确性达98%以上.     

真空预压法加固机理分析

真空预压法的传统观念认为真空预压加固软土地基中总应力是恒定不变的,在土体中产生负的超静孔隙水压应力。通过分析传统观念的矛盾之处,指出矛盾的产生是由于假设总应力不变而引起的,进而推导出在真空预压加固软土地基中总应力是变化的,在土体中产生的是正的孔隙水压力,真空预压法和堆载预压法有效应力增长值均是孔隙中超静孔隙水压应力消散而产生的孔压差值。从应力路径与变形的关系方面,说明了真空预压法是等向均匀体积收缩,加固区外土体产生主动土压力,土体呈拉裂破坏。     

Experimental investigation on microstructure behavior of premixed methane-air flame-flow interaction in a semi-vented chamber

To explore the premixed methane-air flame microstructure behavior and the flame-flow interaction,the premixed methane/air flame was studied in a semi-vented chamber.A high speed camera and schlieren images methods were used to record the processes of interaction between rarefaction wave and flame.Meanwhile,a pressure sensor was utilized to catch the pressure variation in the process of flame propagation.The experiment results showed that the interference of rarefaction wave on flame caused the flame front structure change,which led to the flame transition from laminar to turbulent quickly.The rarefaction wave intervened in the flame by turning the flame front surface into dentiform structure.The violent turbulent combustion began to appear in part of the flame front and spreaded to the whole flame front surface.The rarefaction also decreased the flame propagation speed.     

真空预压法加固淤泥地基的效果分析

深圳市宝安区裕安路软基采用真空预压法加固.主要是加固淤泥层,其软基平均淤泥厚度达到10 m以上,地基施加相当于80 kPa荷载的真空压力,90 d后地基表面沉降量可达到1 m以上,地基平均固结度超过90%,达到设计要求.加固后的软土地基的含水量明显减小,压缩模量和抗剪强度明显提高.证明采用真空预压法加固淤泥地基是行之有效的方法.     

CFD modeling to study the effect of particle size on dispersion in 20l explosion chamber: An overview

Mine disasters occur predominantly due to methane or coal dust explosion or a combination of both.Among the top ten worst coal mine disasters in India, nine are due to coal dust explosion. The current paper describes a general overview of the parameters causing dispersion leading to coal dust explosion,and computational fluid dynamics(CFD) simulation study to observe the effects of particle size on dispersion in Indian coal mines. Turbulent kinetic energy(TKE) and velocity vector path of dust-air mixture and dust-free air were simulated to understand their effects on coal dust dispersion. The TKE contours and velocity vector paths for dust-free air were uniform and symmetrical due to resistance-free path available. The TKE contours and velocity vector paths for dust-air mixture shows the asymmetrical distribution of contours, due to entrainment of air with dust particles. Vortices were observed in velocity vector paths which gradually diminish on increment of time sequence. These vortices are dead centres where velocity and coal dust particles concentration are both zero.     

真空渗透茧层的测试与分析

在不同相对真空度、不同渗透水温度、不同渗透剂的环境下测试茧层吸水量,当真空渗透茧层时,相对真空度是影响渗透效果的关键因素,相对真空度越高茧层吸水量越大,但存在最大值;提高渗透水温或者渗透水中加助剂,在相对真空度较低时效果明显,相对真空度越大时这种效果有逐渐减弱的趋势,并在相对真空度为-94 kPa时,各实验茧层吸水量接近相等,通过研究证明,现在缫丝中采用真空渗透技术后,附加使用渗透助剂是没有必要的.