Professor of School of Engineering, Design and Built Environment, Western Sydney University, Australia. His research interests cover Industry 4.0, Additive Manufacturing, Advanced Engineering Materials and Structures (Metals and Composites), Multi-scale Modelling of Materials and Structures, Metal Forming and Metal Surface Treatment.
2024-02-24
2024-01-04
2023-11-02
Abstract—The secondary flow generated within curved ducts accompanies a substantial change in flow structure due to the imbalance between centrifugal forces and transverse pressure gradient. The current study investigates the effect of changing bend angle on the evaporative cooling of an airstream via spray of water in fogging mode. The experimental Particle image velocimetry (PIV) technique has been implemented for visualizing the secondary flow layout when an air-water mixture travels through the bend duct. The bend angles considered are (45o, 90o and 135o) at velocities of (5, 3.75 and 2.5 m/s) for air flow through 50 cm square duct. PIV results manifested that a single pair of counter rotating vortices appears at 45o bend angle, while the other two bend angles evinced two pairs of vortices (four-cell pattern) across the duct cross-section. The water spray was set to tilt at three orientations, namely (45o, 0o and – 45o) to the axial flow direction to suit the change in bend angle. ANSYS FLUENT 19.R1is used in numerical simulation with RNG-k-ε turbulent model to study the spray characteristics which impacts the cooling process. The best cooling of the airstream is obtained when the water is sprayed axially, i.e. at 0o, prior to the 135o bent duct ranking 30% reduction in temperature corresponding to 6.5% improvement in heat transfer between the two phases. Index Terms—Curved duct, Secondary flow, Evaporative cooling, Inlet Fogging, (PIVLAB) Technique, Bend angle Cite: Akeel A. Nazzal and Abdulsattar J. Hasan, "Effect of Flow Structure on Air-Water Mixing Process at Different Bend Angles," International Journal of Mechanical Engineering and Robotics Research, Vol. 11, No. 12, pp. 923-936, December 2022. DOI: 10.18178/ijmerr.11.12.923-936 Copyright © 2022 by the authors. This is an open access article distributed under the Creative Commons Attribution License (CC BY-NC-ND 4.0), which permits use, distribution and reproduction in any medium, provided that the article is properly cited, the use is non-commercial and no modifications or adaptations are made.
