Effect of O₂ concentration in ambient mixture and multiphase radiation on pollutant formation in ECN spray-A

Abstract

This study investigates the formation and evolution of soot and NO_X in a high-pressure constant-volume combustion chamber. This work focuses on the effect of multiphase thermal radiation and O₂ dilution in ambient/exhaust gases, sometimes also referred to as exhaust gas recirculation (EGR), qualitatively and quantitatively. The spray-A case (n-dodecane as fuel) from Engine Combustion Network (ECN) is used as the target condition. Two different soot modelling approaches have been considered: a semi-empirical two-equation model and a detailed method of moments with interpolative closure (MOMIC) model. A multiphase photon Monte Carlo (PMC) solver with line-by-line (LBL) spectral data is used to resolve radiative heat transfer. Results show that the effect of radiation on soot is minimal in spray-A. Inclusion of radiation modelling, on the other hand, marginally reduces NO prediction. Both peak soot and NO formation increase with O₂ content in the ambient gas. Oxygen content in ambient gas is also found to have significant effect on soot sizes as the mean soot diameter increases along with considerable widening of the diameter distribution with the increase of O₂ percentage in the ambient gas.

Keywords:

• ECN
• radiation
• EGR
• soot
• NO_X

Disclosure statement

No potential conflict of interest was reported by the author(s).

ORCID

Somesh P. Roy http://orcid.org/0000-0002-7365-2304

Additional information

Funding

Part of this work used the Extreme Science and Engineering Discovery Environment (XSEDE) [59], which is supported by National Science Foundation grant number ACI-1548562. The XSEDE system ‘comet’ at the San Diego Supercomputer Center at UC San Diego was utilised for some simulations through allocation ENG170021.