Effects of Triangular Nozzle Geometry on the Deformation and Breakup of Liquid Jets in Crossflow

ABSTRACT Liquid‐jet deformation and breakup in crossflow underpin atomization processes (e.g., automotive spray painting). Three‐dimensional simulations were conducted for Newtonian (NW) and shear‐thinning (SV) jets ejected from triangular (tip‐forward: TS, vertex‐up: TV) and circular (CR) nozzles. The TS jet was highly unstable and broke up rapidly, whereas TV and CR jets were relatively stable. At u G = 10.0 m/s, the jet height at x = 1.5 mm for CR dropped from 0.540 (NW) to 0.152 mm (SV), showing that shear‐thinning behavior promotes breakup even in stable geometries. The aerodynamic energy received by the TS jet was about 1.5 times that of the CR jet in the NW case, whereas the SV jet retained only about 13%, demonstrating the coupled effects of geometry and rheology on jet instability. These findings provide quantitative guidelines for nozzle design and operating conditions in atomization systems handling non‐Newtonian fluids.