High-fidelity simulation of primary breakup of a "spray G" gasoline jet with an adaptive mesh refinement and volume-of-fluid method 2020-01-0826
Efficient atomization of a gasoline jet is essential to the performance of gasoline direct injection (GDI) engines. This paper presents a numerical investigation of the primary breakup of a gasoline surrogate jet. The fuel properties and injection condition are chosen based on the X-ray experiment performed at Argonne National Lab (Duke et al, Exp. Therm. Fluid Sci., 88:608-621, 2017). The surrogate fuel has a low volatility and thus no phase change occurs in the atomization process. The nozzle geometry and operation conditions are similar to the Engine Combustion Network (ECN) ``Spray G". We focus the present study on the near field where inter-jet interaction is of secondary importance. Therefore, we have considered only one of the eight jets in the original Spray G injectors. The liquid is injected from the inlet into a chamber with stagnant gas. To mimic the internal liquid flow in the original injector, an angle is introduced between the liquid inflow and the inner hole axis. A parametric study on the inlet angle is carried out. The adaptive multiphase flow solver, Basilisk, is used for the present simulations. The gas-liquid interface is captured by a momentum-conserving volume-of-fluid method. The adaptive mesh refinement technique is employed to focus high mesh resolution only near the gas-liquid interface and regions with turbulent flows. The numerical results are compared against the X-ray experimental measurements for the jet deflection angle and the temporal variation of penetration length. The lambda-2 vortex-identification criterion is used to show the turbulent gas flow induced by the atomizing jet. Influenced by the non-zero inlet angle, the breakup dynamics of the liquid jet and drop statistics vary over the azimuthal angle.