Morphological variations of in-flame and exhaust soot particles associated with jet-to-jet variations and jet–jet interactions in a light-duty diesel engine

Abstract The variations in soot particle morphology due to jet-to-jet variations and jet–jet interactions have been investigated in a single-cylinder, optically accessible light-duty diesel engine by conducting thermophoretic particle sampling and subsequent transmission electron microscope (TEM) imaging of both in-flame and exhaust soot particles. To this end, the soot sampling experiments were conducted for three different jet configurations including two single-jets (Jet A and Jet B) and a double-jet (Jet AB however, the high jet–jet interaction at fixed injection duration conditions causes the increased number of soot particles compared with the single-jet cases, suggesting higher soot formation in the jet–jet interaction region. Both the soot aggregate and primary particle sizes of the double-jet with the fixed injection duration are lower than those of the single-jets, implying that the soot particles in the jet–jet interaction region are in the earlier stage of soot formation. The same trend is observed in the exhaust samples, albeit the differences are much less. It is likely due to the progression in soot formation/oxidation occurring inside the cylinder of the engine before the particles exit through the exhaust. Compared to marked variations in the soot particle sizes, the fractal dimension is largely unchanged due either to jet-to-jet variations or jet–jet interactions in both in-flame and exhaust soot particles.

[1]  D. E. Rosner,et al.  Simultaneous measurements of soot volume fraction and particle size/ Microstructure in flames using a thermophoretic sampling technique , 1997 .

[2]  Gilles Bruneaux,et al.  Study of Air Entrainment of Multi-hole Diesel Injection by Particle Image Velocimetry - Effect of Neighboring Jets Interaction and Transient Behavior After End of Injection. , 2010 .

[3]  Thomas Dreier,et al.  Assessment of soot particle-size imaging with LII at Diesel engine conditions , 2015 .

[4]  R. L. Wal,et al.  Soot nanostructure: dependence upon synthesis conditions , 2004 .

[5]  D. Tree,et al.  Soot processes in compression ignition engines , 2007 .

[6]  Chenxi Sun,et al.  Impact of rail pressure and biodiesel fueling on the particulate morphology and soot nanostructures from a common-rail turbocharged direct injection diesel engine , 2016 .

[7]  Choongsik Bae,et al.  Detailed Characterization of Morphology and Dimensions of Diesel Particulates via Thermophoretic Sampling , 2001 .

[8]  B. Derjaguin,et al.  Theory of thermophoresis of large aerosol particles , 1965 .

[9]  Effect of Jet-Jet Interactions on the Liquid Fuel Penetration in an Optical Heavy-Duty DI Diesel Engine , 2013 .

[10]  Suk Ho Chung,et al.  Structural effects on the oxidation of soot particles by O2: Experimental and theoretical study , 2013 .

[11]  Charles J. Mueller,et al.  Effects of Oxygenated Compounds on Combustion and Soot Evolution in a DI Diesel Engine:Broadband Natural Luminosity Imaging , 2002 .

[12]  M. Musculus,et al.  Effects of spray targeting on mixture development and emissions formation in late-injection low-temperature heavy-duty diesel combustion , 2009 .

[13]  P. Mcmurry,et al.  Structural Properties of Diesel Exhaust Particles Measured by Transmission Electron Microscopy (TEM): Relationships to Particle Mass and Mobility , 2004 .

[14]  Sanghoon Kook,et al.  Uncertainty in Sampling and TEM Analysis of Soot Particles in Diesel Spray Flame , 2013 .

[15]  Size Distribution and Structure of Wall-Deposited Soot Particles in an Automotive-Size Diesel Engine , 2013 .

[16]  D. Foster,et al.  In-Cylinder Soot Deposition Rates Due to Thermophoresis in a Direct Injection Diesel Engine , 1992 .

[17]  Dennis L. Siebers,et al.  Soot in diesel fuel jets: effects of ambient temperature, ambient density, and injection pressure , 2004 .

[18]  T. Aizawa,et al.  Direct Sampling, TEM Analysis and Optical Measurement of Soot Particles at Different Axial Locations in a Transient Spray Flame , 2011 .

[19]  S. Pischinger,et al.  Analysis of the particle size distribution in the cylinder of a common rail DI diesel engine durin , 2000 .

[20]  M. Ketzel,et al.  Experimentally determined human respiratory tract deposition of airborne particles at a busy street. , 2009, Environmental science & technology.

[21]  S. Kook,et al.  Nanostructure Analysis of In-flame Soot Particles under the Influence of Jet-Jet Interactions in a Light-Duty Diesel Engine , 2015 .

[22]  John E. Dec,et al.  The Effects of Injection Timing and Diluent Addition on Late-Combustion Soot Burnout in a Di Diese , 2000 .

[23]  Constantine M. Megaridis,et al.  Morphological Description of Flame-Generated Materials , 1990 .

[24]  R. A. White,et al.  Air–fuel mixing and combustion in a small-bore direct injection optically accessible diesel engine using a retarded single injection strategy , 2009 .

[25]  J. Dec,et al.  Extinction Measurements of In-Cylinder Soot Deposition in a Heavy-Duty DI Diesel Engine , 2001 .

[26]  Michael Boot,et al.  Flame lift-off length and soot production of oxygenated fuels in relation with ignition delay in a di heavy-duty diesel engine , 2011 .

[27]  L. Pickett,et al.  In-Flame Soot Sampling and Particle Analysis in a Diesel Engine , 2013 .

[28]  Caroline L. Genzale,et al.  Transmission Electron Microscopy of Soot Particles sampled directly from a Biodiesel Spray Flame , 2011 .

[29]  Joakim Pagels,et al.  Experimental determination of deposition of diesel exhaust particles in the human respiratory tract , 2012 .

[30]  Lyle M. Pickett,et al.  Study of Soot Formation and Oxidation in the Engine Combustion Network (ECN), Spray A: Effects of Ambient Temperature and Oxygen Concentration , 2013 .

[31]  Juhun Song,et al.  Examination of the oxidation behavior of biodiesel soot , 2006 .

[32]  Gilles Bruneaux,et al.  Mixing process in high pressure diesel jets by normalized laser induced exciplex fluorescence Part II Wall impinging versus free jet , 2005 .

[33]  I. Glassman.  Soot formation in combustion processes , 1989 .

[34]  Bo Yang,et al.  Soot measurements at the axis of an ethylene/air non-premixed turbulent jet flame , 2003 .

[35]  Sanghoon Kook,et al.  Soot volume fraction and morphology of conventional and surrogate jet fuel sprays at 1000-K and 6.7-MPa ambient conditions , 2011 .

[36]  T. Aizawa,et al.  High-Resolution Transmission Electron Microscopy of Soot Directly Sampled at Different Axial Locations in Diesel Spray Flame , 2011 .

[37]  D. Kittelson.  Engines and nanoparticles: a review , 1998 .

[38]  Sanghoon Kook,et al.  Transmission Electron Microscopy of Soot Particles Directly Sampled in Diesel Spray Flame - A Comparison between US#2 and Biodiesel Soot , 2011 .

[39]  R. Dobashi,et al.  Effect of particle morphology on thermophoretic velocity of aggregated soot particles , 2009 .

[40]  F. G. Emmerich.  Evolution with heat treatment of crystallinity in carbons , 1995 .

[41]  Constantine M. Megaridis,et al.  Morphology of flame-generated soot as determined by thermophoretic sampling , 1987 .

[42]  A. Coppalle,et al.  Influence of Sampling and Storage Protocol on Fractal Morphology of Soot Studied by Transmission Electron Microscopy , 2010 .

[43]  Ümit Özgür Köylü,et al.  Effect of operating conditions on the size, morphology, and concentration of submicrometer particulates emitted from a diesel engine , 2006 .

[44]  Sanghoon Kook,et al.  Soot Volume Fraction and Morphology of Conventional, Fischer-Tropsch, Coal-Derived, and Surrogate Fuel at Diesel Conditions , 2012 .

[45]  J. Sjöholm,et al.  Air-Entrainment in Wall-Jets Using SLIPI in a Heavy-Duty Diesel Engine , 2012 .

[46]  M. Choi,et al.  Effects of engine operating conditions on morphology, microstructure, and fractal geometry of light-duty diesel engine particulates , 2005 .

[47]  D. Su,et al.  Diesel soot toxification. , 2013, Environmental science & technology.

[48]  D Mark,et al.  Characterization of Particles from a Current Technology Heavy-Duty Diesel Engine , 2000 .

[49]  Bengt Johansson,et al.  Influence of jet–jet interactions on the lift-off length in an optical heavy-duty DI diesel engine , 2013 .

[50]  Tiago L. Farias,et al.  Fractal and projected structure properties of soot aggregates , 1995 .

[51]  Raj Sekar,et al.  Morphological investigation of the microstructure, dimensions, and fractal geometry of diesel particulates , 2002 .

[52]  Robert A. Fletcher,et al.  The evolution of soot precursor particles in a diffusion flame , 1998 .

[53]  E. Hawkes,et al.  The planar imaging of laser induced fluorescence of fuel and hydroxyl for a wall-interacting jet in a single-cylinder, automotive-size, optically accessible diesel engine , 2015 .

[54]  D. Kittelson,et al.  Kinetics and visualization of soot oxidation using transmission electron microscopy , 2004 .

[55]  Aromatic Additive Effect on Soot Formation and Oxidation in Fischer-Tropsch Diesel (FTD) Spray Flame -Morphology and Nanostructure Analysis of In-Flame Soot Particles via HRTEM- , 2013 .

[56]  Caroline L. Genzale,et al.  Effect of Ignition Delay on In-Cylinder Soot Characteristics of a Heavy Duty Diesel Engine Operating at Low Temperature Conditions , 2009 .

[57]  Magín Lapuerta,et al.  Effect of engine operating conditions on the size of primary particles composing diesel soot agglomerates , 2007 .

[58]  H. Burtscher.  Physical characterization of particulate emissions from diesel engines: a review , 2005 .

[59]  D. E. Rosner,et al.  Fractal Morphology Analysis of Combustion-Generated Aggregates Using Angular Light Scattering and Electron Microscope Images , 1995 .

[60]  M. Frenklach,et al.  A detailed kinetic modeling study of aromatics formation in laminar premixed acetylene and ethylene flames , 1997 .

[61]  V. Muzyka,et al.  On the carcinogenic risk evaluation of diesel exhaust: benzene in airborne particles and alterations of heme metabolism in lymphocytes as markers of exposure. , 1998, The Science of the total environment.

[62]  M. Musculus,et al.  Conceptual models for partially premixed low-temperature diesel combustion , 2013 .

[63]  Gang Lv,et al.  Evolution of the nanostructure, fractal dimension and size of in-cylinder soot during diesel combustion process , 2011 .

[64]  Lyle M. Pickett,et al.  Jet-Wall Interaction Effects on Diesel Combustion and Soot Formation , 2005 .

[65]  A Numerical Study of the Influence of Different Operating Conditions on the Combustion Development in an Automotive-Size Diesel Engine , 2015 .

[66]  T. Aizawa,et al.  Sizing of Soot Particles in Diesel Spray Flame -A Qualitative Comparison between TEM Analysis and LII/Scattering Laser Measurements , 2013 .

[67]  Sorensen,et al.  The Prefactor of Fractal Aggregates , 1997, Journal of colloid and interface science.

[68]  O. Armas,et al.  Impact of engine operating modes and combustion phasing on the reactivity of diesel soot , 2013 .

[69]  D. Broday,et al.  Deposition of fractal-like soot aggregates in the human respiratory tract , 2011 .

[70]  S. Kook,et al.  Structural evolution of soot particles during diesel combustion in a single-cylinder light-duty engine , 2015 .

[71]  D. Su,et al.  Cytotoxicity and inflammatory potential of soot particles of low-emission diesel engines. , 2008, Environmental science & technology.

[72]  Sanghoon Kook,et al.  Influence of fuel injection timing and pressure on in-flame soot particles in an automotive-size diesel engine. , 2014, Environmental science & technology.

[73]  M. Richter,et al.  Lift-Off Length in an Optical Heavy-Duty Diesel Engine: Effects of Swirl and Jet-Jet Interactions , 2015 .

[74]  J. Dec,et al.  Diffusion-Flame / Wall Interactions in a Heavy-Duty DI Diesel Engine , 2001 .

[75]  D. E. Rosner,et al.  Size- and Structure-lnsensitivity of the Thermophoretic Transport of Aggregated “Soot” Particles in Gases , 1991 .

[76]  Rolf D. Reitz,et al.  Effects of Piston Bowl Geometry on Mixture Development and Late-Injection Low-Temperature Combustion in a Heavy-Duty Diesel Engine , 2008 .

[77]  E. Hawkes,et al.  The shortening of lift-off length associated with jet–wall and jet–jet interaction in a small-bore optical diesel engine , 2014 .

[78]  Kyeong-Ook Lee,et al.  Evolution in size and morphology of diesel particulates along the exhaust system , 2004 .