Influence of confinement geometry on ignition behavior of dust deposits

Effects of holding geometry on spontaneous combustible dust ignition are studied. Spontaneous ignition of coal dust deposited on a flat hot surface (1D case) and trapped between two hot surfaces (2D geometry), forming the shape of a wedge, is analyzed using lab-scale experiments and a mathematical model. The solution is obtained by assuming a temperature polynomial of third (one-dimensional) and fifth order (two-dimensional), in the energy conservation equation where the source term is defined using a 1-step Arrhenius type equation. The angle in wedge configuration is varied from 10° to 150° in steps of 10°. The results predicted by the mathematical model compare well with the trends shown by the experimental data. Consequent safety measures associated with dust layers trapped in corners or wedges are discussed.