NUMERICAL STUDY OF THE INTERNAL FLOW AND PRIMARY BREAKUP OF INTERNAL INTERSECTING-HOLE NOZZLES BASED ON OPENFOAM

Compared to conventional single cylindrical-hole nozzles, internal intersecting-hole nozzles have been gradually applied in practice due to their high discharge coefficient and significant advantages in promoting jet breakup. In this paper, a numerical study was conducted to evaluate the mechanism of the internal flow and jet breakup of an internal intersecting-hole nozzle. With this aim, a Multi-fluid-Quasi-VOF (Volume of Fluid) model coupled with the large eddy simulation (LES) model was constructed in the OpenFOAM framework with the consideration of three separate fluid phases: liquid, vapor, and gas. The mass transfer due to cavitation was modeled based on the heterogeneous nucleation theory. Momentum interactions between the fluids were considered including drag force, surface tension force, and virtual mass force. The proposed models were validated with the existing experimental data. The results show that the internal intersecting-hole nozzle suppresses cavitation within the nozzle, leading to higher fuel mass flow rate and discharge coefficient than those of the single-hole nozzle. Under the influence of internal impact for the internal intersecting-hole nozzle, the surface waves with larger amplitude and wavelength evolute on the diffusion surface rather than the intersection surface, yielding a fan-shaped spray. Additionally, the internal impact effect can be significantly enhanced by increasing the intersecting angle from 20° to 25°, thereby noticeably improves the near field primary breakup.