Determination of Iron Burning Velocity Using the 20-l Sphere

Abstract

Numerical simulations are used to predict the consequences of dust explosions. One key parameter for modelling the flame propagation is the burning velocity. This velocity represents the consumption rates of the reactants by the flame front. The burning velocity depends on the characteristics of the mixture and on the characteristics of the flow (especially the turbulence characteristics). Experiments are needed to determine the relationship between the burning velocity and the characteristics of the turbulence. In this paper, experiments in the standardized 20-Liter explosion sphere are performed to study the burning velocity of iron dust. Burning velocity is deduced from the evolution of the pressure inside the closed vessel. Different tests with different ignition delays (i.e. different times between the end of the dust dispersion and the ignition of the mixture) are performed. Indeed, the turbulence intensity at the moment of ignition varies according to this ignition delay. Thus, the influence of turbulence intensity on the burning velocity can be analysed and a relationship between these two quantities can be proposed.