Dust explosions are time-dependent flame propagation processes. Their descr
iption with "lumped parameter models" like the K-St value are of Limited va
lidity only. More evidence of the process of flame propagation may be expec
ted from an investigation of the flame velocity being composed by the lamin
ar and turbulent velocities and the flow velocity. In the present paper the
influences of the dust concentration and the flow velocity have been inves
tigated by experiments in tube apparatus of three different diameters showi
ng the dominating influence of the flow velocity and the turbulent rms velo
city on the flame propagation.
In addition, laminar and turbulent flame propagation has been investigated
by an appropriate numerical model. Furthermore flow structures and particle
distributions have been computed in a real size grain silo to assess the e
ffects of possible explosions. (C) 2000 Elsevier Science Ltd. All rights re
served.