Influence of Inflow Boundary Conditions on High-Pressure Fuel Injection: Assessment Based on Large Eddy Simulation Approach

The Engine Combustion Network case Spray A with a high-pressure fuel injection is at typical operating conditions of Diesel engines. Detailed pieces of information on this experiment are available, which supports a high-fidelity Large Eddy Simulation (LES) with real fluid thermodynamics. An internal injector flow simulation with the needle movement measured during the experiments is used to provide a realistic boundary condition for the fuel spray simulation. Two spray simulations have been conducted: one with a constant velocity profile and one with the velocity distribution obtained from a separate injector internal flow simulation. Peculiar emphasis is placed on the velocity and turbulence distribution to quantify the influence of spray inlet boundary conditions. The fuel injection is modeled with a single-phase approach applying adequate resolution to capture phase boundaries. Observations from simulation results indicate a significant influence of the inlet boundary conditions on fuel distribution and penetration length, turbulent mixing, and enthalpy propagation.