3. Shadow and refractometric methods

A. Yu Vasiliev, V.P. Maslov, A.A. Sviridenkov, O.G.Chelebyan, V.I.Yagodkin
Central Institute of Aviation Motors, Russia, Moscow.

Comparison of drop size measurements in sprays nozzle obtained with SHADOWGRAPHY AND PDPA techniques.

Fuel sprays with droplet size spectra in the range from 10 to 100 μm have been measured with a direct particle imaging Shadowgraphy (PIS) technique and phase-Doppler-particle anemometer (PDPA). The modern Shadowgraphy technique, which is being used for visualizing droplets, observed in the spray field produced by airblast atomizers, is based on high resolution imaging with pulsed backlight illumination. This technique is independent of the shape and material of the particles, and allows for the investigation of sizes down to 5µm when using the appropriate imaging system and light source. Davis 8.4 software has been used for the image processing. The sizing algorithm consist of two steps first one is to locate the particles in the given field of view and the second step is to analyze it for size, position and shape. Each measurement point covers an area of about 2mm by 3mm. The results of both systems are compared with respect to the Sauter mean diameter, D32. It was found that the shadowgraphy-based D32 agrees within 6% with the PDPAbased measurements in field of main concentration of drop. The Shadowgraphy based D32 larger than the PDPA-based except spray boundary, where D32 smaller.
Full text paper