Measurements of Liquid Length, Vapor Penetration, Ignition Delay, and Flame Lift-Off Length for the Engine Combustion Network ‘Spray B’ in a 2.34 L Heavy-Duty Optical Diesel Engine

摘要

This paper presents new measurements of liquid and liftoff lengths, vapor penetration, and ignition delay using the Engine Combustion Network (ECN) ‘Spray B’ injector in a 2.34 L skip-fired heavy-duty optical engine. The data from the Spray B injector, having three 90-micron holes, are compared with previously existing constant-volume vessel data using both the Spray B injector as well as the ECN Spray A injector, which has a single 90-micron axial hole. The new data were acquired using Mie scattering, OH* chemiluminescence imaging, schlieren imaging, and incylinder pressure measurements. This paper presents data from estimated isentropic-core top-dead-center conditions with ambient densities of 15.2 and 22.8 kg/m3, temperatures of 800, 900, and 1000 K, and for both non-reacting (0% and 7.5% O_2) and reacting (13, 15, and 21% O_2) injections of n-dodecane at fuel-rail pressures of 500, 1000, and 1500 bar. Particular attention is given to the data analysis process during transient injection, and boundary condition uncertainty. In addition to the hole of interest (#3), measurements from all three Spray B holes demonstrate that the hole-to-hole variations are small, but may indicate that the influence of internal sac flows, as well as orifice geometry, are important. In addition to the ensemble-averaged data presented here, the full dataset including cycle-to-cycle variability has also been published to an online-database available at https://ecn.sandia.gov for computer model validation. A companion paper makes a preliminary comparison of these data to Reynolds-averaged Navier Stokes solutions using Lib-ICE to simulate Spray B with a sector mesh.