Fibers Explosion Severity: a Parametric Study on the Fiber Geometry

Even though explosive incidents involving organic fibrous materials have happened in a number of industries, the literature has very few research about the explosibility of fibers. This may have to do with people's lack of awareness of the possibility of explosions caused by fibers, which are frequently thought to be unlikely to explode. Nevertheless, they may provide a significant risk which needs to be taken into account throughout a risk assessment process. More specifically, only a small number of studies regarding fiber explosion modelling has been published in order to gain a better understanding of the primary controlling factors which can affect the explosion severity. Such studies primarily refers to an equivalent diameter approach, in which the elongated fiber is modelled as an equivalent sphere with an effective diameter. This approach, while useful in calculating the primary explosion characteristics, is inherently incapable of differentiating between the effects of increasing either the fiber length or the diameter. A variety of physical and chemical processes, including heat transfer between external and internal particles, pyrolysis and/or devolatilization reactions, and the combustion of volatiles, take place during a fiber explosion. These processes exhibit distinct characteristic times which vary depending on the fiber diameter and length. A comprehensive mathematical model that can account for the cylindrical-like geometry of a fiber can explain this discrepancy. This makes possible to differentiate between the effects of varying both the fiber length and the diameter, so demonstrating through a parametric analysis how such parameters can affect the severity of the explosion.