Volume of fluid analysis using large eddy simulation on standard engine combustion network injectors

Accurate prediction of fuel injection and jet formation under diesel-like conditions requires understanding the coupled thermo-fluid processes inside injector nozzles, including pressure-driven acceleration, viscous losses, cavitation, interfacial dynamics, and convective heat transfer. This study numerically investigates these processes for an oxygenated fuel (OME₃) and a conventional diesel surrogate (n-dodecane) using large-eddy simulations with a Volume-of-Fluid approach and real nozzle geometries from standard ECN Spray A, C, and D injectors. OME₃ exhibits higher liquid density than n-dodecane, resulting in lower exit velocity but greater mass flow and denser near-nozzle jets. The divergent Spray C nozzle promotes inlet separation and cavitation, reducing discharge coefficient and jet core density, whereas convergent nozzles (Spray A and D) yield fuller, attached flows and higher discharge efficiency. Despite geometric differences, both fuels show similar internal pressure distributions, indicating that nozzle design dominates over fuel properties in determining internal hydraulics. From a thermal perspective, OME₃ reaches slightly higher liquid temperatures due to weaker turbulent heat transfer and enhanced viscous heating. Overall, the simulations reveal the combined influence of fuel density, viscosity, and nozzle geometry on discharge characteristics, jet structure, and thermal state, offering physics-based insights for optimizing injector and fuel design in clean, high-efficiency diesel combustion systems.