Role of Chemical Kinetics on the Detonation Properties of Hydrogen / Natural Gas / Air Mixtures

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Role of Chemical Kinetics on the Detonation
Properties ofHydrogen / Natural Gas / Air
Mixtures
Laboratoire de Combustion et Systèmes Réactifs

• N. Chaumeix, S. Pichon, F. Lafosse, N. Udari,
  C.-E. Paillard

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MOTIVATIONS

• GREEN HOUSE EFFECT REDUCTION
• Combustion is a major contributor, CO, CO2, NOx,
  Soot
• Biofuels
• Natural gas
• Hydrogen
• NATURAL GAS
• Relatively low emission, CO2, PAH and soot
• High octane number
• HYDROGEN AS AN ADDITIVE TO NATURAL GAS
• Increase of the flammability domain,
• Increase of the stability range

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MOTIVATIONS

• HYDROGEN AS AN ADDITIVE TO NATURAL GAS
• Production and Storage
• Economically interesting
• Adaptation for multiple use
• Increase the risk of explosion and detonation

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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

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CORRELATION BETWEEN ? AND ?

• H2/CH4/O2 mixture
• CH4/CH4H2 0.4, ? 0.75 P1 10 kPa T1
  20C
• Velocity   DC.J  1800 m.s-1 (Dexp 2218 ? 14
  m.s-1)
• Von Neumann parameters
• T2N 1380 K
• P2N 250 kPa

Evaluation of t For these conditions
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EXPERIMENTAL SETUP

• Auto-ignition Delay Times

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EXPERIMENTAL SETUP

• Auto-ignition Delay Times

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EXPERMENTAL SETUP

• Detonation Parameter Measurements

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EXPERIMENTAL CONDITIONS

• Auto-ignition Delay times
• Mixtures CH4/H2/O2 in 99 of Argon
• CH4/CH4H2 0 0,4 0,8
• ? 0,4 0,75 1
• 1000 K ? T5 ? 1500 K
• 0,15 ? P5 ? 0,25 MPa
• Detonation Parameters
• Mixtures CH4/H2/O2
• CH4/CH4H2 0 0,2 0,4 0,6
• ? 0,75 1
• P1 10 et 20 kPa

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AUTO-IGNITION DELAY TIMES

• Strong decrease with
• Temperature
• Equivalence ratio

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AUTO-IGNITION DELAY TIMES

• Strong decrease with
• Temperature
• Equivalence ratio

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AUTO-IGNITION DELAY TIMES

• Strong increase with
• Methane content

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AUTO-IGNITION DELAY TIMES

• Strong increasewith Pressure

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CORRELATIONS

• From the experimental data

Average error lt 14
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DETAILED KINETIC MECHANISM VALIDATION
REFERENCE SPECIES REACTIONS
Gas Research Institute 53 325
Lawrence Livermore National Laboratory 155 689
LEEDS 37 175
KONNOV 127 1027
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MODEL vs EXPERIMENTS

• Konnovs Mechanism
• is most suitable

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MODEL vs EXPERIMENTS

• Konnovs Mechanism is most suitable

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MODEL vs EXPERIMENTS

• depends on the equivalence ratio

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MODEL vs EXPERIMENTS

• Different mechanisms from the literature were
  used
• The comparison between the experiments and the
  prediction depends on the amount of H2 in the
  mixture
• The most reliable is KONNOVs mechanism which
  will be used
• Needs to be improved

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DETONATION PARAMETERS

• Chapman- Jouguet (TCJ, PCJ, VCJ) Parameters
• ZND (TZND, PZND) Parameters
• Auto-ignition Delay Times of CH4/H2/air Mixtures
• Package CHEMKIN
• EQUIL SENKIN codes

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RESULTS
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CONDITIONS ZND
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AUTO-IGNITION DELAY TIME BEHIND THE LEADING SHOCK
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DETONATION CELL SIZE

• Sensitivity to detonation
• ? with equivalence ratio
• ? with methane content

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CONCLUSION

• A new experimental database
• Auto-ignition delay times
• Correlations valide for detonation conditions
• Detonation cell size
• Validation of a detailed chemical kinetic
  mechanism
• Konnovs Mechanism the most reliable
• Needs to be improved

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AKNOWLEDGEMENT

• This work was financially supported by
  Commissariat à lEnergie Atomique (CEA) under the
  contract number CNRS / CEA NSAV 32030.

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COMPARISON WITH CHENG OPPENHEIM
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INTRODUCTION

• Déflagration Inflammation qui se propage par
  diffusion de chaleur et de radicaux

• Détonation Couplage entre une onde de choc ()
  et une zone réactionnelle (?)

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