Large-Eddy Simulation on the Influence of Injection Pressure in Reacting Spray A

Abstract

The Engine Combustion Network (ECN) Spray A target case corresponds to high-pressure liquid fuel injection in conditions relevant to diesel engines. Following the procedure by Wehrfritz et al. 2016, we utilize large-eddy simulation (LES) and flamelet generated manifold (FGM) methods to carry out an injection pressure sensitivity study for Spray A at 50, 100 and 150 MPa. Comparison with experiments is shown for both non-reacting and reacting conditions. Validation results in non-reacting conditions indicate relatively good agreement between the present LES and experimental data, with some deviationin mixture fraction radial profiles. In reacting conditions, the simulated flame lift-off length (FLOL) increases with injection pressure, deviating from the experiments by 4-14%. The respective deviation in ignition delay time (IDT) is noted to be within 10-20%. Analysis of the underlying chemistry manifold implies that the noted discrepancies can be explained partially by the differences between experimental and computational mixing processes.