Offset jet ejection angle effect in combined wall and offset jets flow: numerical investigation and engineering correlations

Abstract

The present paper deals with a numerical study of turbulent flow which combines a wall jet and parallel offset jet. A parametric study was presented to pick out the offset ratio as well as the offset jet ejection angle influence on the merge point, combined point, upper vortex center and lower vortex center positions. Empirical correlations have been provided as a function of the offset ratio and the ejection angle. The main results obtained from the present investigation show that increasing the ejection angle displaces the merge point, the combined point and the vortices centers more upstream along the axial direction which accelerate the merging process launching. Furthermore, for higher value of the ejection angle, these mentioned points approach the horizontal wall along the lateral direction. Keywords Finite volume • Combined jets • Ejection angle • Merge point • Offset ratio List of symbols d Nozzle width (m) Greek symbols Kinematic viscosity (m²/s) Fluid density (kg/m 3) Offset jet ejection angle (OJEA) Subscripts 0 Exit value (at the nozzle exit) a Ambient value m Maximum value t Turbulent value Abbreviations WOJ Wall offset jet LWJ Lower wall Jet UOJ Upper offset jet SOJ Single offset Jet UVC Upper vortex center LVC Lower vortex center MP Merge point CP Combined point OJEA Offset jet ejection angle

Analysis of turbulent wall jet impingement onto a moving heated body

“…They showed that results are closer to the experimental data that were obtained with the RSM model, and the entropy changes of gases were examined with the RSM model. In the study by Hnaien et al (2019), turbulent combined wall and offset jet flow (WOJ) was investigated numerically. The main aim of the study is to examine the effect of shear jet launch angle (OJEA) a and shear rate H on the dynamic properties of WOJ flow, such as the axial and lateral positions of the junction (MP) junction.…”