Several phenomena (e.g., initial turbulence level, overdriving, underdriving, etc.) affect the measurement of dust explosion parameters in the 20 L and 1 m³ standard test vessels. Estimating the role of each phenomenon is crucial to understand the discrepancies observed over the years between the data collected using these vessels. In this work, we focus on the role of the pyrotechnic ignitors on the pressure trend and the temperature distribution. We run explosion tests in the 20 L vessel to measure the pressure–time history generated by the explosion of pyrotechnic ignitors. Moreover, we performed CFD simulations to simulate the spatial/temporal evolution of the temperature map from the hot core due to the igniter explosion toward the vessel walls. The explosion of the pyrotechnic ignitors shows a significant increase of pressure in the 20 L vessel, suggesting that flame propagation is occurring inside the vessel. Furthermore, the localized increase of temperature due to the ignitor explosions, diffuse, and then uniformize much more rapidly in the 20 L vessel than in the 1 m³ vessel. The flame propagation generated by the ignitors is very relevant in the 20 L sphere leading to the overdriving phenomenon. This result justifies the fact that for many organic dusts, the deflagration index values measured in the 20 L are much higher than those measured in the 1 m³ vessel. CFD simulations show that the hot core generated by the ignitors dissipate much faster in the 20 L vessel than in the 1 m³ vessel, due to the higher turbulence level of the smaller vessel. Therefore, dusts whose combustion is controlled by particle heating are more prone to sustain combustion in the 1 m³ than in the 20 L vessel.

中文翻译：

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关于烟火点火器在粉尘爆炸试验中的作用：20 L 和 1 m3 爆炸容器的比较

几种现象（例如，初始湍流水平、超速驱动、驱动不足等）会影响 20 L 和 1 m ³粉尘爆炸参数的测量标准测试容器。估计每种现象的作用对于了解多年来使用这些容器收集的数据之间观察到的差异至关重要。在这项工作中，我们关注烟火点火器对压力趋势和温度分布的作用。我们在 20 升容器中进行爆炸测试，以测量烟火点火器爆炸产生的压力-时间历程。此外，我们还进行了 CFD 模拟，以模拟由于点火器爆炸导致的热芯温度图向容器壁的空间/时间演变。烟火点火器的爆炸显示 20 升容器中的压力显着增加，表明容器内部正在发生火焰传播。此外，由于点火器爆炸引起的局部温度升高，³艘。点火器产生的火焰传播与导致超速现象的 20 L 球体非常相关。该结果证明，对于许多有机粉尘，在 20 L 中测得的爆燃指数值远高于在 1 m ³容器中测得的值。CFD 模拟表明，点火器产生的热芯在 20 L 容器中消散得比在 1 m ³容器中快得多，这是由于较小容器的湍流水平较高。因此，通过颗粒加热控制燃烧的粉尘在 1 m ^{3 中}比在 20 L 容器中更容易持续燃烧。