LARGE EDDY SIMULATION OF ULTRA-HIGH INJECTION PRESSURE DIESEL SPRAY IN MARINE DIESEL ENGINES

Large Eddy Simulation (LES) scheme and a new modified breakup model have been implemented in the OpenFOAM freeware for simulating ultra-high injection pressure diesel and Marine Diesel Fuel (MDF) sprays. Also, the dynamic of dispersed droplet has been modelled by the Lagrangian Particle Tracking (LPT) scheme. The proposed LES/LPT method has been validated by matching it against published experimental data and numerical results of Fluent software under different injection pressures of up to 300 MPa. Furthermore, comparisons have been drawn with Reynolds Averaged Navier-Stokes (RANS) simulations. Spray shape and geometry, droplet penetration and size as well as equivalent ratio are compared with experimental data. Based on the obtained numerical results, main spray characteristics have been simulated accurately by LES and RANS, but the LES results display greater precision in transient conditions. Later, numerical sensitivity of the LES results to the mesh resolution is discussed. Finally, it is found that the proposed LPT/LES scheme along with the advanced breakup model gives more accurate results than the conventional RANS model under ultra-high injection pressures. This advanced scheme has been implemented to investigate the influence of Marine Fuel on spray characteristics