Study of vortex structure in high number density spray based onturbulence correlation

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A laser 2-focus velocimeter (L2F) was used for measurements of velocity and size of droplets in diesel sprays injected intermittently into the atmosphere from aninjector with an orifice of 0.113mm in diameter. The rail pressure was set at 80MPa, and the solenoid energizing time was set at 3.0ms. Three measurement positions were located on the plane 6, 9 and 12 mm from the nozzle exit. The integral scale of turbulence in velocity, the one in size and the one in data rate were evaluated by correlation based slotting technique. The integral scale of turbulence in velocity is larger than the one in size and data rate. Every scale increases with the distance of droplet flight.Phase Doppler technique was used for the measurements of the velocity, size and flight angle of droplets in diesel sprays injected intermittently into the atmosphere from an injector. In the vicinity of the spray axis, droplets have the components of radially outward velocity in addition to that of the spray axis direction velocity. And the velocity components of spray axis direction decreased with the radius. It is understood that the trajectory of the spray observed diagonally backward come ftom the difference in velocities near the spray axis. Droplets which move inward from the periphery of the spray change their directions of velocity vector from the radially inward to the spray axis. A combination of the droplet movements which were mentioned above is considered to make up a vortex.