A Progress Review on Soot Experiments and Modeling in the Engine Combustion Network (ECN)

Abstract

The 4th Workshop of the Engine Combustion Network (ECN) was held September 5-6, 2015 in Kyoto, Japan. This manuscript presents a summary of the progress in experiments and modeling among ECN contributors leading to a better understanding of soot formation under the ECN “Spray A” configuration and some parametric variants. Relevant published and unpublished work from prior ECN workshops is reviewed. Experiments measuring soot particle size and morphology, soot volume fraction (fv), and transient soot mass have been conducted at various international institutions providing target data for improvements to computational models. Multiple modeling contributions using both the Reynolds Averaged Navier-Stokes (RANS) Equations approach and the Large-Eddy Simulation (LES) approach have been submitted. Among these, various chemical mechanisms, soot models, and turbulence-chemistry interaction (TCI) methodologies have been considered

Soot and spectral radiation modeling for high-pressure turbulent spray flames

“…Total soot mass predictions from both models were low compared to experiment, by at least a factor of two, and neither model captured the rapid initial transient. The differences with respect to the present results can be attributed to the differences in the mixing model used for the PDF results reported in; 13 IEM was used there. As shown in Fig.…”

“…WSR and PDF model total-soot-mass-versus-time results obtained using the same 54-species chemical mechanism and a similar two-equation soot model were presented for a shorter-injection-duration case in. 13 There the WSR model yielded approximately twice as much soot as the PDF model. Total soot mass predictions from both models were low compared to experiment, by at least a factor of two, and neither model captured the rapid initial transient.…”

“…The mechanism showed good agreement for ignition delay and lift-off length in previous Spray A simulations. 13,25 Some results obtained using a different chemical mechanism 31 are included, for comparison purposes. The second mechanism consists of a main mechanism of 96 species, appended with a submechanism of 37 species for polycyclic aromatic hydrocarbons (PAHs): 133 total species.…”

“…In all cases, the initial chamber gas density is 22.8 kg/m 3 , the liquid fuel injection pressure is 150 MPa, and the injection duration is 5.5 ms. For reacting cases, the ambient gas composition includes 15% O2 with the remainder being N2 (75.15%), CO2 (6.22%) and H2O (3.62%), and the ambient temperature ranges from 750 K to 1200 K. The baseline Spray A case corresponds to an ambient gas temperature of 900 K, and this is the condition that is analyzed most extensively in this paper. Reacting experimental data include ignition delays and lift-off lengths, total soot mass as a function of time after start of injection (SOI) and spatial distributions of soot volume fraction, 13 and radiant fractions and spatially and spectrally resolved radiative intensities. 14 For the nonreacting case, the ambient gas composition is pure N2 and the ambient temperature is 900 K.…”

Characterization of Spray A flame structure for parametric variations in ECN constant-volume vessels using chemiluminescence and laser-induced fluorescence

“…In an additional collaborative publication, differences in nozzle geometry and hydraulic behavior are revealed, giving rise to related parameters downstream of the injector orifice [5]. More recently, soot formation was studied extensively, including both experimental and numerical comparisons [6]. The detailed and structured approach of the ECN has also given rise to several publications on numerical combustion modeling [7][8][9][10][11].…”