Dispersion process of the spray formed by an air-assisted injector

This paper reports on an experimental study of the dispersion process of an injected spray with the objective of optimizing its characteristics. A phase Doppler anemometer was used to measure the injected spray from a fuel precharging type injector, under an open air condition. Average mean diameters and velocities of the fuel droplets were calculated for repetitive injections. The average mean velocity showed reasonable agreement with the velocity obtained by visualization. At higher load conditions, atomization was achieved with high speed air flow such that the mean diameter was reduced. From medium to full load conditions, the fuel droplets were distributed in a tube like profile due to the shape of the nozzle. The first group of droplets had high velocity and small mean diameter in contrast to the second group. Relative velocity was not very small even in the fine droplets within the air flow from the injector, as expected.