Study of explosion physics

用于发电的化石燃料消耗量的增加导致温室气体二氧化碳在大气中的浓度明显上升。为了减少燃烧碳基燃料的副产品二氧化碳的产生，已经促进了在燃气轮机和内燃机中使用较高氢含量的气体燃料用于固定发电。与这些燃料有关的爆炸危险远高于目前发电厂使用的天然气。安全指南需要一种方法来分类与这些新的高氢含量燃料相关的相对危险。事实上，需要一个更好的系统来分类化学工业中使用的普通燃料，并通过铁路和卡车运输。这对于减轻重大事件非常重要，例如2013年7月6日在魁北克的Lac-Megantic发生的火车出轨爆炸造成35人死亡。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，燃料越危险。由于用于测量MESG的设备规模较小，因此进行实验相对便宜，因此存在广泛的燃料数据。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引爆的敏感性的适当参数。爆震是一种超音速燃烧波，其传播过程与火焰不同。实验测量的爆轰单元尺寸通常用于表征气体的爆轰感度，但±50%的测量不确定度对于安全准则是不可接受的。另一个可以使用的参数是临界管直径，但它需要一个相对较大的设备，这使得它不切实际的获得大量的燃料的数据。提出了一种方法来测量的基础上，通过一个管道，配备了一系列孔板的超音速燃烧波的传播的燃料引爆的敏感性。对于不同的燃料-空气混合物，将测量可以支持以比理论最高火焰速度快的平均速度传播的燃烧波的传播的最小（或临界）孔板直径。与MESG非常相似，临界孔板直径越小，混合物越易爆炸。将进行实验来研究超声速燃烧波的传播。在圆钢管内测量了不同燃料的临界孔直径。实验是用燃料-空气混合物进行的，其中孔板直径逐渐增加，直到可以传播超声速燃烧波。另一个实验将在一个通道中进行，高速视频将捕捉燃烧波传播经过一系列障碍物时的结构。可视化的结果，沿着与计算流体动力学建模，将有可能识别的方式超声速燃烧波在充满障碍物的管传播的物理。这一实验方案将为制定用于运输和使用普通燃料的安全准则提供数据。这些准则有可能限制严重意外爆炸的次数，从而尽量减少财产和环境损害，并最终防止生命损失。该计划将提供多个高素质人才的培训，包括一个硕士，两个博士和五个本科生。

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.