Chemical Kinetics of Combustion

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Chemical Kinetics of Combustion Philippe

modeling validation Kinetic Modeling Some

1 Chemical Kinetics of Combustion Philippe Dagaut CNRS-INSIS ICARE 1c, Avenue de la Recherche Scientifique - Orléans- France Introduction Experimental facilities for modeling validation Kinetic Modeling Some results Conclusions INSIS, 8 Mars

2 INTRODUCTION Ubiquitous combustion INSIS, 8 Mars

3 Introduction (cont'd) RESSOURCES 2010 Projections 98% transport fuels are oil-derived INSIS, 8 Mars

4 Introduction (cont'd) PM10 (<10 microns) INSIS, 8 Mars

5 Introduction (cont'd) GHG: CO 2 INSIS, 8 Mars

6 Introduction (cont'd) TO ADDRESS THESE ISSUES/CHALLENGES: ALTERNATIVE FUELS NEW ENGINE TECHNOLOGIES SCIENCE INSIS, 8 Mars

7 Introduction (cont'd) Chemical Kinetics (combustion/troposphere) HC,NOx,COx RH+OH R+H2O R+O2 RO2 RO2+NO RO+NO2 HO2+NO OH+NO2 2RO2 2RO+O2,... RO2+HO2 RO2H+O2,... HC,NOx,COx NO2+h NO+O; O+O2+M O3 HC,NOx,COx INSIS, 8 Mars

8 Introduction (cont'd) Chemical Kinetics Constrain the model(s) by using Experimental data Model Global parameters: Ignition delays (initiation reactions, R+O 2 ) Burning velocities (H fluxes) Detailed information: Species concentrations (~ all processes) Initiations: RH R + H RH R + R RH + O 2 R + HO 2 Propagations: RH + X R + HX (X= H, O, OH, HO 2, CH 3, HCO ) Terminations: R + H RH R + R RH Different types of reactors : ST, PF, PSR, Flames (laminar premixed, opposed flow) INSIS, 8 Mars

Introduction (cont'd) Alternative fuels In recent years, research activities on synthetic and bio-derived fuels have increased significantly in

9 Introduction (cont'd) Alternative fuels In recent years, research activities on synthetic and bio-derived fuels have increased significantly in order to reduce dependence of the air transport sector on petroleum. fossil { renewable { *XTL: Gas/Coal/Waste/Renewable to Liquid INSIS, 8 Mars

10 Introduction (cont'd) Alcohols Methyl esters Ethyl esters Furanics 2-G Biofuels O OH Polymers of terpenes & isoprenoids (farnesane) O O O O O O Source ( # 3G biofuels) lignocellulose Algae #, lignocellulose Algae #, lignocellulose Lignocellulose (Fructose, glucose) Trees & plants (α-, β-pinene) Potential use Current knowledge Interest Aviation?, Automotives Automotives Automotives Automotives Aviation, Automotives Kinetic data & model for simple alcohols; can be extended to larger alcohols Kinetic data & model for simple esters; extended to larger ones; little information for unsaturated esters Very little information e.g. ethylpropionate Essentially test in engines, + W-I-P Essentially test in engines, Su + W-I-P High High High (?) High 2G-CSafe INSIS, 8 Mars

11 EXPERIMENTAL FACILITIES for modeling validation INSIS, 8 Mars

12 Experimental Facilities Variable pressure JSR 1-40 atm Sooting flames Pool fire Smoke point apparatus DCN apparatus I.C. Engines INSIS, 8 Mars

13 Experimental Facilities What we can learn Conc. profiles, Pathways, pollutants Soot, PAHs, kinetics of atmos. soot rxns Soot, PAHs Smoke point Cetane Number (ignition) Soot, PAHs, HCCI kinetics, sensitization, control INSIS, 8 Mars

14 Experimental Set-Up Stables species measurements H 2, O 2, H 2 O, CO, CO 2, CH 2 O, CH 4, C 2 -C 16, NO x, SO x Fuel (+NOx) +N2 O2+N2 Low-P samples taken by sonic probe sampling for GC analyses (Capillary GC FID TCD Heating Wire columns Carboplot, DB-624, CP-Al 2 O 3 -KCl; TCD, FID, MS). GC/MS Probe+TC Piston On-line FTIR, GC analyses (FID/MS) C-balance checked for every sample Bulb LOPAP FTIR Exhaust PAH-Trap Sample HPLC UV-Fluo GC/MS/FID INSIS, 8 Mars

15 Experimental Set-Up Less-stable or unstable species measurements (H 2 O 2, HO 2 ) Fuel+N2 O2+N2 AOM cw laser Mirror ring down cavity Pump TC & Probe Mirror Piezo Mod Photodiode Signal: JSR set-up with sonic sampling and cw-crds quantification of H 2 O, H 2 O 2, HO 2, CH 2 O, C 2 H 4 J. Am. Chem. Soc. 136 (47), (2014); Fuel 158 (1) (2015). INSIS, 8 Mars

Lawrence Berkeley National Laboratory, CA.

Laboratories, Livermore, CA; Dept of Chemistry, Bielefeld

Abdullah University of Science and Technology, Thuwal,

16 Experimental Set-Up BL 9.02 JSR/MBMS TOF The Advanced Light Source (ALS) at Lawrence Berkeley National Laboratory, CA. JSR team: Combustion Research Facility, Sandia National Laboratories, Livermore, CA; Dept of Chemistry, Bielefeld University, Germany; CNRS-INSIS, Orleans, France; King Abdullah University of Science and Technology, Thuwal, Saudi Arabia; Dept of Mechanical and Aerospace Engineering, Princeton University, Princeton, NJ. INSIS, 8 Mars

17 KINETIC MODELING INSIS, 8 Mars

18 Modeling Need accurate kinetics, thermochemistry, and transport data Use inputs from theory and measurements and also estimations by analogy Need accurate data that are used to constrain the model INSIS, 8 Mars

19 Modeling: Hierarchical structure of chemical kinetic schemes H2-O2 CO CO2 CH 2O CH3OH CH4 C2H6 C2H4 C2H2 C3 >C4 INSIS, 8 Mars

20 Modeling: hydrocarbons oxidation Cool flame High-T INSIS, 8 Mars

21 Modeling Olefin + HO2 O2 RH +X -XH R O2 R + Olefin H+Olefin ROOH RH HO2 RO2 RO2 RO + RO + O2 RO+OH O2 QOOH Cyclic Ether + OH O2 OOQOOH Olefin + Carbonyl Compound + OH HOOQ OOH OQ OOH + OH Decomposition OQ O + OH INSIS, 8 Mars

22 Modeling New reactions evidenced through JSR/ALS experiments: HOMs formation Extended reaction scheme of OOQOOH radical. The pathways included in 2-Methylhexane kinetic model are annotated with dashed arrows; the extended third O 2 addition pathways studied in this work are annotated with blue solid lines. 36 th Symp. Int l on Combustion, submitted (2016) INSIS, 8 Mars

23 Results: HCCI control via Sensitization by Ozone, NO, and NO 2 Production of ozone/discharge In-Cylinder Pressure [bar] [O 3 ] = 19.6 ppm [NO] = 19.9 ppm [NO 2 ] = 19.7 ppm Without O 3, NO and NO 2 Heat Release Rate [J/CAD] [O 20 3 ] = 19.6 ppm [NO] = 19.9 ppm [NO 2 ] = 19.7 ppm Without O 3, NO and NO Crank Angle Degree [CAD] In-cylinder pressure and heat release rate traces without any species and with 20 ppm of each species separately injected. Mazurier et al. Proc. Combust. Inst. 35 (3) (2015). INSIS, 8 Mars

Results: HCCI control via Sensitization by Ozone, NO, and NO 2 Simple computations to understand the process Ozone mainly decomposes into oxygen molecules (O 2 ) and O-atoms, FAST.

NO is mostly consumed by reaction with HO 2, resulting in the initial oxidation of the fuel via C 8 H 18 +O 2 C 8 H 17 +HO 2, SLOW, OH radicals are produced via NO+HO 2 NO 2 +OH, FAST.

24 Results: HCCI control via Sensitization by Ozone, NO, and NO 2 Simple computations to understand the process Ozone mainly decomposes into oxygen molecules (O 2 ) and O-atoms, FAST. Then, the fuel reacts directly with O-atoms to yield OH radicals and rapid oxidation of the fuel ensues: C 8 H 18 +O C 8 H 17 +OH (a) followed by C 8 H 18 +OH C 8 H 17 +H 2 O (b). NO is mostly consumed by reaction with HO 2, resulting in the initial oxidation of the fuel via C 8 H 18 +O 2 C 8 H 17 +HO 2, SLOW, OH radicals are produced via NO+HO 2 NO 2 +OH, FAST. Subsequently, rapid fuel consumption can take place via (b) due to OH production. Consequently, as nitric oxide requires an HO 2 radical to yield an OH radical, this explains the lower effect of NO on ignition delays compared to ozone. NO 2 addition: OH production results from a longer sequence of rxns: CH 3 +NO 2 CH 3 O+NO; NO 2 +HO 2 HONO+O 2 ; HONO+M NO+OH+M; and NO+HO 2 NO 2 +OH. Because nitrogen dioxide presents intermediate reactions before OH production, its effect on ignition delays is the lowest of the three additives considered. INSIS, 8 Mars

25 Conclusions & Perspectives Detailed chemical kinetic models need laboratory experiments (simple to sophisticated) + kinetics & thermo data for validation prior to use in CFD modeling (HCCI, GT, ) Due to the hierarchical structure of kinetic reaction mechanisms, simple to complex chemical systems need to be studied and sub-models validated For modeling the combustion of complex fuels: appropriate surrogates are also needed HCCI (Homogeneous Charge Compression Ignition) is interesting for fuel savings, but the auto-ignition event is difficult to control: chemical kinetics can help via Engine experiments combined with modeling including detailed chemistry INSIS, 8 Mars

Oxidation of C 3 and n-c 4 aldehydes at low temperatures

Oxidation of C 3 and n-c 4 aldehydes at low temperatures M. Pelucchi*, A. Frassoldati*, E. Ranzi*, T. Faravelli* matteo.pelucchi@polimi.it * CRECK-Department of Chemistry, Materials and Chemical Engineering