Interaction between gas explosion flame and deposited dust

In order to study the patterns for local gas explosion inducing deposited dust combustion, the process of dust kicking-up and participating in gas explosion is numerically simulated. The pressure wave of local gas explosion kicks up deposited dust, then the flame triggers raised dust to burn and further spread. Coal dust participation can accelerate the methane air flame propagation in the tube, which is shown by the increasing of flame propagating velocity, the flame temperature and the combustion duration. The temperature-time curves of complex flames display an apparent structure of double peaks, and the FWHMs (full width at half maxima) of temperatures vary at different deposited coal dust concentrations. The FWHM at 80 g/m(3) has no significant difference compared with the FWHM with no dust. Therefore, 80 g/m(3) can be esteemed as the lower limit for the secondary explosion (dust participating and methane/dust mixed-combusting). Furthermore, the effect of pressure wave velocity on dust kicking-up is studied. It is found that dust diffuses sufficiently when the pressure wave velocity lies in the range of 140 m/s-300 m/s. (C) 2017 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.