ICHS, International Conference on Hydrogen Safety, September 8-10, 2005, Pisa (Italy) 1 Role of Chemical Kinetics on the Detonation Properties of Hydrogen / Natural Gas / Air Mixtures N. Chaumeix, S. Pichon, F. Lafosse, N. Udari, C.-E. Paillard Laboratoire de Combustion et Systèmes Réactifs

ICHS, International Conference on Hydrogen Safety, September 8-10, 2005, Pisa (Italy) 2 MOTIVATIONS GREEN HOUSE EFFECT REDUCTION  Combustion is a major contributor, CO, CO 2, NOx, Soot …  Biofuels  Natural gas  Hydrogen NATURAL GAS  Relatively low emission, CO 2, PAH and soot  High octane number HYDROGEN AS AN ADDITIVE TO NATURAL GAS  Increase of the flammability domain,  Increase of the stability range

ICHS, International Conference on Hydrogen Safety, September 8-10, 2005, Pisa (Italy) 3 MOTIVATIONS HYDROGEN AS AN ADDITIVE TO NATURAL GAS  Production and Storage  Economically interesting  Adaptation for multiple use  Increase the risk of explosion and detonation

ICHS, International Conference on Hydrogen Safety, September 8-10, 2005, Pisa (Italy) 4 AIMS OF THE STUDY Oxidation of Hydrogen / Methane based Mixtures  For conditions close to detonation  Auto-ignition delay times  Validation and selection of a detailed kinetic mechanim Determination of the detonation parameters  Chapman-Jouguet and ZND conditions  Experimental measurements of cell size

ICHS, International Conference on Hydrogen Safety, September 8-10, 2005, Pisa (Italy) 5 {H 2 /CH 4 /O 2 } mixture : CH 4 /CH 4 +H 2 = 0.4,  =0.75; P1 = 10 kPa; T1 = 20°C Velocity : D C.J = 1800 m.s -1 (D exp = 2218  14 m.s -1 ) Von Neumann parameters:  T 2N = 1380 K  P 2N =250 kPa Triple points Leading shock Reaction zone  : induction distance  : ignition delay time behind the leading shock behind the leading shock Evaluation of  For these conditions CORRELATION BETWEEN AND 

ICHS, International Conference on Hydrogen Safety, September 8-10, 2005, Pisa (Italy) 6 EXPERIMENTAL SETUP Auto-ignition Delay Times I.E.E.E PUMPS Pressure Gage T Air Mixture He Driven Section Diaphragm High Pressure Knife N2N2 C4 C3 C2 C

ICHS, International Conference on Hydrogen Safety, September 8-10, 2005, Pisa (Italy) 7 EXPERIMENTAL SETUP Auto-ignition Delay Times

ICHS, International Conference on Hydrogen Safety, September 8-10, 2005, Pisa (Italy) 8 EXPERMENTAL SETUP Detonation Parameter Measurements

ICHS, International Conference on Hydrogen Safety, September 8-10, 2005, Pisa (Italy) 9 EXPERIMENTAL CONDITIONS Auto-ignition Delay times  Mixtures: CH 4 /H 2 /O 2 in 99% of Argon  CH 4 /CH 4 +H 2 = 0 ;0,4; 0,8   =0,4; 0,75; 1  1000 K  T 5  1500 K  0,15  P 5  0,25 MPa Detonation Parameters  Mixtures: CH 4 /H 2 /O 2  CH 4 /CH 4 +H 2 = 0 ; 0,2 ; 0,4 ; 0,6   =0,75 ; 1  P 1 = 10 et 20 kPa

ICHS, International Conference on Hydrogen Safety, September 8-10, 2005, Pisa (Italy) 10 AUTO-IGNITION DELAY TIMES Strong decrease with  Temperature  Equivalence ratio

ICHS, International Conference on Hydrogen Safety, September 8-10, 2005, Pisa (Italy) 11 AUTO-IGNITION DELAY TIMES Strong decrease with  Temperature  Equivalence ratio

ICHS, International Conference on Hydrogen Safety, September 8-10, 2005, Pisa (Italy) 12 AUTO-IGNITION DELAY TIMES Strong increase with  Methane content

ICHS, International Conference on Hydrogen Safety, September 8-10, 2005, Pisa (Italy) 13 AUTO-IGNITION DELAY TIMES Strong increase with Pressure

ICHS, International Conference on Hydrogen Safety, September 8-10, 2005, Pisa (Italy) 14 CORRELATIONS From the experimental data From the experimental data Average error < 14 %

ICHS, International Conference on Hydrogen Safety, September 8-10, 2005, Pisa (Italy) 15 DETAILED KINETIC MECHANISM VALIDATION REFERENCESPECIESREACTIONS Gas Research Institute Lawrence Livermore National Laboratory LEEDS37175 KONNOV

ICHS, International Conference on Hydrogen Safety, September 8-10, 2005, Pisa (Italy) 16 MODEL vs EXPERIMENTS Konnov’s Mechanism Konnov’s Mechanism is most suitable is most suitable

ICHS, International Conference on Hydrogen Safety, September 8-10, 2005, Pisa (Italy) 17 MODEL vs EXPERIMENTS Konnov’s Mechanism is most suitable Konnov’s Mechanism is most suitable

ICHS, International Conference on Hydrogen Safety, September 8-10, 2005, Pisa (Italy) 18 MODEL vs EXPERIMENTS depends on the equivalence ratio depends on the equivalence ratio

ICHS, International Conference on Hydrogen Safety, September 8-10, 2005, Pisa (Italy) 19 MODEL vs EXPERIMENTS Different mechanisms from the literature were used Different mechanisms from the literature were used The comparison between the experiments and the prediction depends on the amount of H 2 in the mixture The most reliable is KONNOV’s mechanism which will be used Needs to be improved

ICHS, International Conference on Hydrogen Safety, September 8-10, 2005, Pisa (Italy) 20 DETONATION PARAMETERS Chapman- Jouguet (T CJ, P CJ, V CJ ) Parameters ZND (T ZND, P ZND ) Parameters Auto-ignition Delay Times of CH 4 /H 2 /air Mixtures Package CHEMKIN  EQUIL & SENKIN codes

ICHS, International Conference on Hydrogen Safety, September 8-10, 2005, Pisa (Italy) 21 RESULTS

ICHS, International Conference on Hydrogen Safety, September 8-10, 2005, Pisa (Italy) 22 CONDITIONS ZND

ICHS, International Conference on Hydrogen Safety, September 8-10, 2005, Pisa (Italy) 23 AUTO-IGNITION DELAY TIME BEHIND THE LEADING SHOCK

ICHS, International Conference on Hydrogen Safety, September 8-10, 2005, Pisa (Italy) 24 DETONATION CELL SIZE Sensitivity to detonation   with equivalence ratio   with methane content

ICHS, International Conference on Hydrogen Safety, September 8-10, 2005, Pisa (Italy) 25 CONCLUSION A new experimental database  Auto-ignition delay times  Correlations valide for detonation conditions  Detonation cell size Validation of a detailed chemical kinetic mechanism  Konnov’s Mechanism the most reliable  Needs to be improved

ICHS, International Conference on Hydrogen Safety, September 8-10, 2005, Pisa (Italy) 26 AKNOWLEDGEMENT This work was financially supported by Commissariat à l’Energie Atomique (CEA) under the contract number CNRS / CEA N°SAV

ICHS, International Conference on Hydrogen Safety, September 8-10, 2005, Pisa (Italy) 27

ICHS, International Conference on Hydrogen Safety, September 8-10, 2005, Pisa (Italy) 28 COMPARISON WITH CHENG & OPPENHEIM

ICHS, International Conference on Hydrogen Safety, September 8-10, 2005, Pisa (Italy) 29 Détonation : Couplage entre une onde de choc ( | ) et une zone réactionnelle (  ) INTRODUCTION Déflagration : Inflammation qui se propage par diffusion de chaleur et de radicaux Zone réactionnelle (gaz brûlés) (gaz frais) Délai (gaz frais) (gaz brûlés) P et T élevées