Characterization of the ECN spray A in different facilities. Part 2: spray vaporization and combustion

Abstract

One of the objective of Engine Combustion Network (ECN), (https://ecn.sandia.gov/) is to provide experimental results with high accuracy in order to validate model and reach new steps in scientific understanding of spray combustion at conditions specific to engines. The ECN community defines different target conditions, experimental diagnostics and post processing methods to facilitate the comparison of experimental and simulations studies performed in different facilities or models. In this context two French laboratories propose two new facilities, based on Rapid Compression Machines to reach the ECN spray A conditions. In this paper, the results of liquid and vapour spray penetration as well as Ignition Delay (ID) and Lift-Off Length (LOL) obtained with these Rapid Compression Machines are compared to the results obtained in the Constant Volume Preburn (CVP) vessel of IFPEN. The specificities of each experimental apparatus allow to bring complementary elements of understanding like confinement effects. In non-reactive condition, the liquid and vapour sprays were characterized by Diffused-Back Illumination and Schlieren technique, and in reactive conditions, the LOL and the ID by OH* chemiluminescence. The analysis of the results with regard to the boundary conditions (temperature, velocity, confinement) make it possible to validate these two new facilities and contribute to enhance the database of ECN, highlighting the confinement effect typical of piston engine operation.