Sam Goo Lee
The Journal of Mechanical Science and Technology, vol. 22, no. 8, pp.1633-1639, 2008

Abstract : In an effort to obtain the significant features associated with the ALR and length/diameter ratio of the final discharge orifice in swirling flows, experimental observations using a 3-D PDPA system were carried out. Profiles of SMD distributions depending on lo/do, correlation between SMD and turbulence intensities in terms of lo/do and correlations between droplet size and turbulence components were quantitatively analyzed. As discussed in a previous literature, an axisymmetric swirl angle of 30o was selected for this investigation because of its strong turbulence levels in the flowfield and finer droplet disintegrations. Three ALRs of 0.093, 0.106, and 0.122 as well as the length/diameter ratio of 0.15, 0.45, and 0.60 were chosen as parameters. Due to the complex interactions in swirling flows under these variables, this experimental observation will be of fundamental importance to the understanding of geometrical effects on spray trajectory. From the observations, it is indicated that increasing the ALR causes the spray development to be more dependent on number density and volume flux. The results indicated that the SMD decreases discernibly with smaller lo/do, substantiating the fact that turbulence intensities are inversely proportional to the SMD. But, lo/do is quite proportional to the SMD.

Keyword : lo/do (length-to-diameter ratio of the final discharge orifice); ALR (Air-to-Liquid Mass Ratio); PDPA (Phase Doppler Particle