title: Ignition behavior of magnesium powder layers on a plate heated at constant temperature.
abstract: The minimum temperature at which dust layers or deposits ignite is considered to be very important in industries where smoldering fires could occur. Experiments were conducted on the self-ignition behavior of magnesium powder layers. The estimated effective thermal conductivity k for modeling is 0.17 W m(-1)K(-1). The minimum ignition temperature (MIT) of magnesium powder layers for four different particle sizes: 6, 47, 104 and 173 μm, are also determined in these experiments. A model was developed describing temperature distribution and its change over time while considering the melting and boiling of magnesium powder. Parameter analysis shown that increasing particle size from 6 to 173 μm increased MIT from 710 to 760 K, and increased thickness of the dust layer led to a decreased MIT. The calculation termination time more than 5000 s didn't significantly impact MIT. Comparing predicted and experimental data showed satisfactory agreement for MIT of magnesium powder layers at various particle sizes. According to the ignition process of magnesium powder layer, a meaningful definition for the most sensitive ignition position (MSIP) was proposed and should be taken into consideration when preventing smoldering fires induced by hot plates.
authors: Fire & Explosion Protection Laboratory, Northeastern University, Shenyang 110819, China. yuanchunmiao@mail.neu.edu.cn
authors: Yuan
authors: Y
authors: Chunmiao
authors: Huang
authors: H
authors: Dezheng
authors: Li
authors: L
authors: Chang
authors: Li
authors: L
authors: Gang
mesh_terms: D004391:Dust; D005390:Fires; D006358:Hot Temperature; D008274:Magnesium; D008962:Models, Theoretical; D010316:Particle Size; D044366:Transition Temperature
chemical_list: D004391:Dust; D008274:Magnesium