Comparative analysis of the main ignition characteristics of coal-water slurry fuel and artificial composite liquid fuel droplets in heated air flow

Experimental studies of ignition regularities were done for coal-water slurry fuel and artificial composite liquid fuel droplets (with sizes less 4 mm) under conditions of radiation and convective heat transfer with heated air flow. The main components of fuels are coal dust, distilled water, plasticizer, and heavy crude oil. Typical stages for induction process were identified by using methods of high-speed (about $10^5$ f/s) video recording. The values of ignition delay time were established for fuel drops at the varying the temperature (600-900 K) and velocity (0.5-5 m/s) of air flow. Approximate expressions were obtained for the prediction of the main characteristics of process - ignition delay time. Analysis of drops ignition regularities was made for four different compositions of coal-water slurry fuel and artificial composite liquid fuel.