Abstract：In order to investigate the air leakage characteristics and heating up law of the spontaneous combustion in an exposed coal pile, a two-dimensional mathematical model for heat and mass transfer of a coal pile was established based on three influential factors that were air pressure, thermal pressure and mass diffusion.Then the air leakage and temperature distribution were analyzed by software Fluent. The results show that the high temperature region always lies in the windward slope where appropriate air velocity and sufficient oxygen supply are available. The reason is that the windward slope has the highest air velocity and oxygen supply in a coal pile, but they decrease far from the windward slope. The case of the leeward slope is contrary. Slow air velocity reduces heating up rate, and a coal pile can be kept safe when the air velocity drops into a critical value. When air velocity rises to a certain value, the effect of air velocity on coal pile spontaneous combustion does not focus on heating up rate but on the high temperature region instead. Several factors such as air velocity, coal pile porosity and stack model should be considered to evaluate coal pile risk. Therefore, fire protection should be strengthened by timely measurement of the factors.

Keyword：spontaneous combustion of coal pile;air leakage distribution characteristic;heating up law;