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Numerical investigation of spontaneous flame propagation under RCCI conditions

Journal Article · · Combustion and Flame
 [1];  [2];  [3];  [1]
  1. Sandia National Lab. (SNL-CA), Livermore, CA (United States)
  2. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
  3. Univ. of Wisconsin, Madison, WI (United States)
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This paper presents results from one and two-dimensional direct numerical simulations under Reactivity Controlled Compression Ignition (RCCI) conditions of a primary reference fuel (PRF) mixture consisting of n-heptane and iso-octane. RCCI uses in-cylinder blending of two fuels with different autoignition characteristics to control combustion phasing and the rate of heat release. These simulations employ an improved model of compression heating through mass source/sink terms developed in a previous work by Bhagatwala et al. (2014), which incorporates feedback from the flow to follow a predetermined experimental pressure trace. Two-dimensional simulations explored parametric variations with respect to temperature stratification, pressure profiles and n-heptane concentration. Furthermore, statistics derived from analysis of diffusion/reaction balances locally normal to the flame surface were used to elucidate combustion characteristics for the different cases. Both deflagration and spontaneous ignition fronts were observed to co-exist, however it was found that higher n-heptane concentration provided a greater degree of flame propagation, whereas lower n-heptane concentration (higher fraction of iso-octane) resulted in more spontaneous ignition fronts. A significant finding was that simulations initialized with a uniform initial temperature and a stratified n-heptane concentration field, resulted in a large fraction of combustion occurring through flame propagation. The proportion of spontaneous ignition fronts increased at higher pressures due to shorter ignition delay when other factors were held constant. For the same pressure and fuel concentration, the contribution of flame propagation to the overall combustion was found to depend on the level of thermal stratification, with higher initial temperature gradients resulting in more deflagration and lower gradients generating more ignition fronts. Statistics of ignition delay are computed to assess the Zel’dovich (1980) theory for the mode of combustion propagation based on ignition delay gradients.
Research Organization:
Energy Frontier Research Centers (EFRC) (United States). Combustion Energy Frontier Research Center (CEFRC); Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States). Oak Ridge Leadership Computing Facility (OLCF); Sandia National Laboratories (SNL-CA), Livermore, CA (United States); Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States)
Sponsoring Organization:
USDOE; USDOE National Nuclear Security Administration (NNSA); USDOE Office of Science (SC)
Grant/Contract Number:
AC05-00OR22725; NA0003525
OSTI ID:
1212348
Alternate ID(s):
OSTI ID: 1870485
OSTI ID: 1246678
Report Number(s):
SAND2022-4546J; KJ0502000; ERKJZN1
Journal Information:
Combustion and Flame, Journal Name: Combustion and Flame Journal Issue: 9 Vol. 162; ISSN 0010-2180
Publisher:
ElsevierCopyright Statement
Country of Publication:
United States
Language:
English

References (28)

Regime classification of an exothermic reaction with nonuniform initial conditions journal October 1980
Burning velocities of mixtures of air with methanol, isooctane, and indolene at high pressure and temperature journal January 1982
Several new numerical methods for compressible shear-layer simulations journal June 1994
A comprehensive modeling study of iso-octane oxidation journal May 2002
Numerical and asymptotic studies of the structure of stoichiometric and lean premixed heptane flames journal March 1997
Triple flames and partially premixed combustion in autoignition of non-premixed turbulent mixtures journal January 1996
Low-storage, explicit Runge–Kutta schemes for the compressible Navier–Stokes equations journal November 2000
Direct numerical simulation of ignition front propagation in a constant volume with temperature inhomogeneities journal April 2006
Direct numerical simulation of ignition front propagation in a constant volume with temperature inhomogeneities journal April 2006
Direct numerical simulations of ignition of a lean n-heptane/air mixture with temperature inhomogeneities at constant volume: Parametric study journal September 2011
Autoignition and front propagation in low temperature combustion engine environments journal November 2011
Computational diagnostics for n-heptane flames with chemical explosive mode analysis journal October 2012
Experimental analysis of propagation regimes during the autoignition of a fully premixed methane–air mixture in the presence of temperature inhomogeneities journal November 2012
Direct numerical simulations of the ignition of lean primary reference fuel/air mixtures with temperature inhomogeneities journal October 2013
Direct numerical simulations of HCCI/SACI with ethanol journal July 2014
The effects of non-uniform temperature distribution on the ignition of a lean homogeneous hydrogen–air mixture journal January 2005
Three-dimensional direct numerical simulation of a turbulent lifted hydrogen jet flame in heated coflow: a chemical explosive mode analysis journal May 2010
Analytical Model for Auto-Ignition in a Thermally Stratified hcci Engine journal August 2007
Terascale direct numerical simulations of turbulent combustion using S3D journal January 2009
Fuel reactivity controlled compression ignition (RCCI): a pathway to controlled high-efficiency clean combustion journal June 2011
Gasoline partially premixed combustion, the future of internal combustion engines? journal June 2011
Multidimensional Simulation of the Influence of Fuel Mixture Composition and Injection Timing in Gasoline-Diesel Dual-Fuel Applications conference April 2008
Integration of a Continuous Multi-Component Fuel Evaporation Model with an Improved G-Equation Combustion and Detailed Chemical Kinetics Model with Application to GDI Engines conference April 2009
Reactivity Controlled Compression Ignition (RCCI) Heavy-Duty Engine Operation at Mid-and High-Loads with Conventional and Alternative Fuels conference April 2011
Boosted HCCI - Controlling Pressure-Rise Rates for Performance Improvements using Partial Fuel Stratification with Conventional Gasoline journal April 2011
Investigation of Fuel Reactivity Stratification for Controlling PCI Heat-Release Rates Using High-Speed Chemiluminescence Imaging and Fuel Tracer Fluorescence journal January 2012
Heavy-Duty RCCI Operation Using Natural Gas and Diesel journal January 2012
Effects of Biofuel Blends on RCCI Combustion in a Light-Duty, Multi-Cylinder Diesel Engine journal April 2013

Cited By (4)

A numerical study on combustion mode characterization for locally stratified dual-fuel mixtures text January 2020
Computational Investigation of Weakly Turbulent Flame Kernel Growths in Iso-Octane Droplet Clouds in CVC Conditions journal July 2019
Optimal Compressed Sensing and Reconstruction of Unstructured Mesh Datasets journal August 2017
Influence of smooth temperature variation on hotspot ignition journal August 2017

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37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
RCCI
autoignition
premixed flame
reactivity stratification
thermal stratification