Large eddy simulation of high-pressure ECN Spray A with the focus on the influence of injection pressure

Due to the rapid advancement in high-performance computation (HPC) capacities, detailed numerical simulations are feasible for complex flows at engine conditions. The simulations aim to enhance our understanding of multiphysics phenomena in such flows that will eventually assist the development of new internal combustion technologies with high thermal efficiency and extremely low emission. The current study presents detailed simulations for the Engine Combustion Network (ECN) Spray A at non-reacting conditions to provide a better understanding of the influence of the injection pressure. A hybrid approach is adopted where Large Eddy Simulation (LES) is employed for the gas phase and a Lagrangian particle tracking approach is chosen for the liquid phase. The Kelvin-Helmholtz Rayleigh-Taylor (KHRT) model is used for the break-up while collision and coalescence are neglected. The evaporation rate is computed using the standard Spalding model whereas the Ranz–Marshall correlation is adopted for the heat transfer between the liquid and gas phases. A high-quality mesh is created. The mesh is locally refined to achieve a minimum mesh size of 0.65 of the nozzle diameter (D). The simulations are conducted using OpenFOAM which is an open source object-oriented C++ computational fluid dynamic (CFD) code. The simulations show good agreement with the measurements for both liquid length and vapour penetration at various injection pressures. The mixture fraction field is well captured at the upstream locations while a slight deviation from the measurements is observed further downstream.