Abstract
A laser 2-focus velocimeter (L2F) was used for the measurements of velocity and size of droplets in a diesel fuel spray near the spray center 15 mm downstream from the nozzle exit. The micro-scale probe of the L2F was consisted of two foci and the distance between them was 14μm. The hole diameter of the tested nozzle was 0.113 mm and the injection pressure was 40 MPa. The light scattered by droplets was detected just after the spray tip reached the measurement position. It was confirmed that the rate of data-sampling should be increased to mega-hertz order for the measurement of a narrow distance between droplets after disintegration. Velocity and size of droplets decreased with the radial distance from the spray center. It was understood that the number density of droplets increased with the radial distance from the spray center in the spray core region.
