Effects of propane pyrolysis on basic flame structures of non-premixed jet flame

Recently, high temperature combustion techniques have been extensively adopted to improve thermal efficiency of combustion devices. When the temperature is sufficiently high, fuel pyrolysis may occur and then the flame structure can be affected. Thus, the understanding flame structure at high temperature coupled with fuel pyrolysis is essential to design burners operated in high temperature environments. In this study, propane was heated up to 1100 K using an electric heater, and the characteristics of fuel pyrolysis and its effects on non-premixed jet flames were experimentally investigated at room temperature. Normalized volume flow rates and components were measured regarding the fuel pyrolysis. The normalized volume flow rates of the propane were increased significantly through the pyrolysis process, and they agreed with numerical results based on an ordinary chemical mechanism. Variations of flame height and soot region were compared for the pyrolysis temperature. Conclusively, in spite of the significant growth in the volume flow rate by the propane pyrolysis, flame height was not significantly affected. On the contrary, the soot region was slightly extended by the fuel pyrolysis. This study will help to extend understanding on jet flame characteristics especially at high temperature conditions.