Propagation and extinction of dust flames in narrow channels

This article has investigated the propagation and extinction of aluminum dust cloud flame in a narrow channel. The burned and burning dust particles act as heat sources and the channel walls act as heat sinks. In this method, discrete heat source has been used to analyze dust combustion in a narrow channel. Using the superposition of sources and sinks, the preheat zone temperature is predicted as an indicator of flame propagation or extinction. Dust concentration and channel width are two major parameters which affect the quenching distance and flame propagating speed. Wall temperature affects the heat loss; and by preheating the walls, quenching distance is reduced and flame propagation speed is increased.     

Radiation heat transfer in transient dust cloud flame propagation

This study investigates the impact of radiation heat transfer and heat conduction on dust cloud combustion. Radiation plays a very important role in the stability of dust cloud flame, and increasing the amount of radiation drastically raises the possibility of instability and explosion in a dust cloud mixture. Flame speed, which is a function of mixture characteristics, can exhibit a fluctuating behavior. By using the discrete heat source method, it would be possible to study the transient propagation of dust flames. Thus, the propagation speed of flame can be obtained, and as time goes by, the transient speed of dust flame will reach its steady state value. By considering the radiation effect, better agreement is observed between the obtained results and experimental data.