Study of explosion physics

用于发电的化石燃料消耗量的增加导致了大气中温室气体二氧化碳浓度的明显上升。为了减少燃烧碳基燃料的副产品二氧化碳的产生，在固定发电的燃气轮机和内燃机中推广使用含氢量较高的气体燃料。与这些燃料相关的爆炸危险明显高于目前发电厂使用的天然气。安全指南需要一种方法对与这些新的高氢含量燃料相关的相对危害进行分类。事实上，需要一个更好的系统来对化学工业中使用的、铁路和卡车运输的普通燃料进行分类。这对于减少像2013年7月6日魁北克省Lac-Megantic火车脱轨引起的爆炸这样的重大事故是很重要的，那次事故造成35人死亡。美国国家消防局建议使用最小爆炸安全间隙（MESG）来设计防爆电气设备，如电动机。燃料-空气混合物的MESG越小，燃料就越危险。由于用于测量MESG的设备规模较小，实验费用相对较低，因此存在各种燃料的数据。MESG对于描述燃料-空气混合物对火焰传播的敏感性是有用的，然而，它不是表征这种混合物对爆炸敏感性的合适参数。爆轰是一种超音速燃烧波，其传播过程与火焰不同。实验测量的爆轰池尺寸通常用于表征气体的爆轰灵敏度，但±50%的测量不确定度对于安全指南来说是不可接受的。另一个可以使用的参数是临界管径，但它需要一个相对较大的仪器，这使得获取大量燃料的数据变得不切实际。提出了一种基于超声速燃烧波在装有一系列孔板的管内传播的燃料爆轰灵敏度测量方法。对于不同的燃料-空气混合物，可以支持燃烧波以比理论最高火焰速度更快的平均速度传播的最小（或临界）孔板直径将被测量。与MESG非常相似，临界孔板直径越小，混合物的可爆性越强。实验将研究超声速燃烧波的传播。在圆钢管中测量不同燃料的临界孔直径。实验是在燃料-空气混合物中进行的，其中孔板直径逐渐增加，直到可以传播超音速燃烧波。另一项实验将在通道中进行，高速视频将捕捉到燃烧波传播通过一系列障碍物时的结构。可视化结果以及计算流体动力学建模将使识别超音速燃烧波在装有障碍物的管道中传播的物理方式成为可能。这一试验项目将为制定用于运输和使用普通燃料的安全准则提供数据。这种准则有可能限制严重意外爆炸的数量，从而最大限度地减少财产和环境损害，并最终防止生命损失。本项目将培养1名硕士、2名博士、5名本科生等多名高素质人才。

The increase in the consumption of fossil fuels for power production has led to a measured rise in the atmospheric concentration of the greenhouse gas carbon dioxide. The use of higher-hydrogen content gaseous fuel in gas turbines and internal combustion engines for fixed power generation has been promoted in order to reduce the production of carbon dioxide, a byproduct of burning carbon based fuel. The explosion hazard associated with these fuels is significantly higher than that for natural gas currently used in power plants. A method to categorize the relative hazard associated with these new high hydrogen content fuels is required for safety guidelines. In fact, a better system is required to categorize common fuels used in the chemical industry and transported by rail and trucks. This is important to mitigate major incidents like the explosion caused by the train derailment in Lac-Megantic, Quebec, on July 6, 2013 that killed 35 people. The National Fire Protection Agency recommends the use of the minimum explosion safe gap (MESG) to design explosion-proof electric equipment, such as electric motors. The smaller the fuel-air mixture’s MESG, the more hazardous the fuel. Because of the small scale of the apparatus used to measure the MESG, experiments are relatively inexpensive to perform, and as a result data exists for a wide range of fuels. The MESG is useful for describing fuel-air mixture sensitivity to flame propagation, however, it is not an appropriate parameter to characterize the sensitivity of such a mixture to detonate. A detonation is a supersonic combustion wave that propagates by a process that is different from that of a flame. The experimentally measured detonation cell size is generally used to characterize detonation sensitivity of a gas, but the ±50% measurement uncertainty is not acceptable for safety guidelines. Another parameter that could be used is the critical tube diameter but it requires a relatively large apparatus that makes it impractical for obtaining data for a large number of fuels. A method is proposed to measure the sensitivity of a fuel to detonate based on the propagation of a supersonic combustion wave through a tube equipped with a series of orifice plates. The minimum (or critical) orifice plate diameter that can support the propagation of a combustion wave propagating at an average velocity faster than the theoretical highest flame velocity will be measured for different fuel-air mixtures. Much like the MESG, the smaller the critical orifice plate diameter the more detonable the mixture. Experiments will be performed to investigate supersonic combustion wave propagation. The critical orifice diameter will be measured for different fuels in a round steel tube. Experiments are performed with a fuel-air mixture where the orifice plate diameter is progressively increased until a supersonic combustion wave can propagate. Another experiment will be carried out in a channel where high-speed video will capture the structure of the combustion wave as it propagates past a series of obstacles. The visualization results, along with computational fluid dynamics modeling, will make possible the identification of the physics involved in the way a supersonic combustion wave propagates in an obstacle laden tube. This experimental program will provide data for the development of safety guidelines to be used for the transport and use of common fuels. Such guidelines have the potential to limit the number of severe accidental explosions, thereby minimize property and environmental damage, and ultimately prevent the loss of life. This program will provide training of multiple highly qualified personnel, including one MASc, two PhDs, and five undergraduate students.