Pneumatic atomisation with coaxial injectors: Measurements of drop size by diffraction method and liquid phase fraction by attenuation method

Experiments were made to determine the drop size distribution in sprays from twin fluid, parallel flow, concentric jet atomizers using air/water and helium/water. Bimodal distribution of diffracted light energy impeded measurements at high injected mass ratios of liquid to gas. The drop size increased with the distance from atomizers and spray axes. The drop size on spray axes had its local maximum with an injection gas velocity of 200 m/s and its minimum with an injection gas velocity of 100 m/s. Using minimum drop diameter of Dp,min = 5.8 microns gave ratios of SMD to MMD consistent with other studies.