Abstract:

The fuel ignition in the rotary kiln with high-temperature air combustion （HTAC） is a nonlinear catastrophe process. In order to investigate this process, a zero-dimension cusp catastrophe model is established according to the heat-flux potential function, with the furnace temperature as the state parameter and with the airflow flux and the air temperature as the controlling parameters. The proposed model is then used to explain the complex ignition phenomenon and unsteady state in the rotary kiln. The results indicate that the variation of high-temperature airflow flux makes the internal energy of the system fluctuate, thus resulting in the ignition or the flameout. However, a high air temperature may decrease the unsteady combustion region. It is also found that, at a high air temperature of more than 973 K, the unsteady region of sawdust combustion in the rotary kiln gradually decreases and finally disappears at 1473 K.

Key words: high-temperature air combustion, rotary kiln, ignition, catastrophe