A brief review on the effect of particle size on the laminar burning velocity of flammable dust: Application in a CFD tool for industrial applications

Several factors influence the rate of flame propagation in dust clouds, such as the chemical composition of the dust, moisture content, particle shape, particle size distribution, flow conditions, pressure, temperature and humidity. For a given material, the particle size is arguably the most important physical property associated with the dust itself. Most dusts encountered in industry are not mono-sized, and particles with different sizes/shapes respond differently to gradients in the flow field. This paper reviews previous work on quantifying the effect of particle size on burning velocity, with particular emphasis on applications related to numerical modelling of dust explosions in the process industries. In the computational fluid dynamics (CFD) tool FLACS-DustEx, which has been developed for simulating large-scale dust explosions, the turbulent burning velocity is calculated using an empirical correlation that incorporates turbulent flow conditions and laminar burning velocity. This paper reviews the effect of particle size on the laminar burning velocity of flammable dusts, and examines a formulation for the laminar burning velocity that takes into account the effect of particle size using the particle-size-dependent Damkohler and Thiele dimensionless numbers.