Fundamental Study on Flame Propagation in Partially-Premixed Spray at Constant Pressure

A basic study of partially-premixed spray combustion has been performed using mono-sized and monodispersed fuel droplet-vapor-air mixtures. Uniform fuel droplet-vapor-air mixtures were generated by the condensation method using rapid expansion of saturated ethanol vapor-air mixtures. Flame speed was measured at various pressures within a constant-pressure combustion chamber. The flame speed decreases with the increase in the pressure. The increasing effect of fine fuel droplets on the flame speed becomes larger with the increase in the pressure on the fuel-lean side. A partially-premixed spray burner was developed to observe the flame structure, which produces uniform fuel droplet-vapor-air stream by the condensation method.