Numerical simulation of diesel injector nozzle flow and in-cylinder spray evolution

A numerical investigation is conducted to survey the flow in a diesel injector and the cylinder. Different CFD models are applied for two-phase flow of the injector and cylinder, i.e. a RANS homogeneous-mixture model is used for the injector analysis, and a LES-based Eulerian-Lagrangian approach for the in-cylinder simulations. The unsteady nature of the SMD (sauter mean diameter) is due to the LES (large eddy simulation) method employment, which is capable of capturing the detailed turbulence mechanism. The contours of volume fraction and viscosity have been displayed across the injector for various injection pressures and included angles. The nozzle flow characteristics are transferred through coupling the boundary information of the exit of the injector to the cylinder flow. This helps to simulate the spray structure in terms of sgs (subgrid-scale) averaged turbulence and fluid mass fraction. The results are significant in terms of spray-wall impingement time and SMD trends with simultaneous variation of the injection angle and pressure. The injector turbulence is calculated based on k-ζ-f method while spray evolution is based on LES approach.