Critical autoignition conditions for a system of particles

Conclusions

• 1. The critical conditions of autoignition for a system of particles have the same form as the critical conditions for the individual particle, but the place of the heat transfer coefficient α is taken by the coefficient α_eff, for which an explicit expression has been found.

• 2. The cooperative effect of the particles is determined by the parameter A, which is inversely proportional to the square of the mean particle diameter.

• 3. This simple model, with the effective heat transfer coefficient, explains the qualitative aspects of the measured relation between ignition temperature and concentration [5] for particles of different diameter and, taking into consideration the remarks relating to supercritical heating, the complex (with maximum and minimum) dependence of ignition temperature on particle diameter.