Measurements of droplets characteristics in a swirl-stabilized spray flame

Experiments have been performed in a kerosene airblast atomized spray flame where the fuel supply is sandwiched between two coswirling air streams. A phase-Doppler particle sizing system was used to measure fuel droplet size, velocity and turbulent kinetic energy of droplets and gas as well as the fuel volume flux within the combustor for two values of air preheat temperature, 200 °C and 400 °C. The results reveal that a small liquid fuel exists in the centre of the combustor and due to larger droplets with the swirl effect; the droplets characteristics (velocity and turbulent kinetic energy) did not follow the gas ones. Based upon these measurements, an optimum swirl number will exist with every atomization and burner arrangement of a liquid-fuelled flame associated and will be different from that associated with the corresponding gas-fuelled flame. The investigated atomizer shows a marked influence of the inlet air temperature on the measured droplet size which may be attributed to the design of the internal airflow, promoting prompt atomization at the dominant atomization mode.