Geometrical effects on spray characteristics of air-pressurized swirl flows

• Published in: Journal of mechanical science and technology Vol. 22; no. 8; pp. 1633 - 1639
• Main Author: Lee, Sam-Goo
• Format: Journal Article
• Language: English
• Published: Heidelberg Korean Society of Mechanical Engineers 01.08.2008; Springer Nature B.V; 대한기계학회
• Subjects: Control; Correlation analysis; Droplets; Drops and bubbles; Dynamical Systems; Engineering; Exact sciences and technology; Fluid dynamics; Fluid flow; Fundamental areas of phenomenology (including applications); Industrial and Production Engineering; Mechanical Engineering; Nonhomogeneous flows; Physics; Rotational flow and vorticity; Sprays; Turbulence; Turbulence intensity; Turbulent flow; Vibration; 기계공학; PDPA (Phase Doppler Particle Analyzer); Volume flux; SMD (Sauter Mean Diameter); length-to-diameter ratio of the final discharge orifice; ALR (Air-to-Liquid Mass Ratio); Number density; /; Rotating flow; Turbulent flow; Electric discharges; Doppler effect; Experimental study; Aspect ratio; Axial symmetry; l0/d0 (length-to-diameter ratio of the final discharge orifice); Air flow; Gas flow; Vortices; Size effect; Droplets; Vortex flow; Orifice flow
• ISSN: 1738-494X; 1976-3824
• DOI: 10.1007/s12206-008-0420-y

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 l o / d o , correlation between SMD and turbulence intensities in terms of l o / d o and correlations between droplet size and turbulence components were quantitatively analyzed. As discussed in a previous literature, an axisymmetric swirl angle of 30° was selected for this investigation because of its strong turbulence levels in the flow-field 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 l o / d o , substantiating the fact that turbulence intensities are inversely proportional to the SMD. But, l o / d o is quite proportional to the SMD.