Abstract
ABSTRACT In this study, two-blade and four-blade swirl inserts with 180°, 270° and 360° pitch angles, φ each were used for the first time to generate swirling flow in plunging water jets to enhance oxygen transfer. The swirl number, S estimated from the geometry varied from 0.4 to 1.0, denoting moderate to strong swirling flow. Oxygen transfer performance of swirling jets was compared to a non-swirl jet and higher values of oxygen transfer coefficient, K L a 20,, were observed in the former. In addition, K L a 20 increased with increasing φ and jet fall height h j . A strong power relationship was observed between K L a 20 and jet velocity v j . However, K L a 20 generally decreased with increasing water depth, h w . It was observed that any flow conditions which increased bubble plume size, penetration depth or swirl cone size and therefore contact time enhanced oxygen transfer and vice versa. Empirical relationships proposed for estimating K L a 20 based on influential jet and pool properties established in previous research had regression coefficient of determination R 2 values ranging from 0.85 to 0.99. Finally, comparison with multiple circular jets from previous studies indicated that higher oxygen transfer values can be achieved using swirl inserts for the same jet power per unit volume.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
