Effect of Cross-Flow Swirl on the Trajectory of Spray in an Annular Passage

Abstract

This paper presents the experimental analysis of the impact of swirl number of cross-flowing air stream on liquid jet spray trajectory at a fixed air flow velocity of 42 m/s with the corresponding Mach number of 0.12. The experiments were conducted for 4 different swirl numbers (0, 0.2, 0.42, and 0.73) using swirl vanes at air inlet having angles of 0 deg, 15 deg, 30 deg, and 45 deg, respectively. Liquid to air momentum flux ratio (q) was varied from 5 to 25. High-speed (at 500 fps) images of the spray were captured, and those images were processed using matlab to obtain the path of the spray at various momentum flux ratios. The results show interesting trends for the spray trajectory in swirling air flow. High swirling flows not only lead to spray with lower radial penetration due to sharp bending and disintegration of liquid jet but also result in spray with large spread and spray area. Based on the results, correlations for the spray path have been proposed, which incorporates the effects of the swirl number of the air flow.