Understanding the role of thermal radiation in dust flame propagation
Abstract
The role of thermal radiation in premixed flame propagation has been a matter of debate for decades. And it is not only a challenging scientific point, it has significant practical implications. For instance, a proposed explanation of the Buncefield explosion (HSL, 2009) was tiny particles were raised by the blast and promoted flame acceleration through enhanced heat exchanges by thermal radiation through the flame front. In dust explosion protection, the flame is implicitly supposed to propagate like a in a gaseous mixtures but if it happens that thermal radiation is dominant for some dusts, many aspects concerning the way to mitigate the explosions for those particular dusts would need to be revised. The present research team (Ben Moussa et al., 2013, 2017; Proust et al., 2017a, 2017b) and another one (Julien et al., 2015) have been working on this subject for some time. The scientific problem was settled and a significant experimental effort was done. It was shown that thermal radiation could accelerates flames possibly to a considerable extent but without any firm confirmation. In the present paper a numerical modelling of this problem is proposed to help understanding the physics of the flames seeded with particles and especially aluminum dust flames. The code uses the discrete element method and was developed from scratch over the last years. Some information to understand how the code work is provided into the paper and the results are compared to the experiments. From this comparison it can be concluded that thermal radiation is readily capable of strongly accelerating dust flames depending on the experimental conditions. Large scale experiments are now needed which however could be complicated to perform.
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