Conditional Moment Closure Modelling of Turbulent Methane Diffusion Flames Presented at: Institute o

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Conditional Moment Closure Modelling of Turbulent
Methane Diffusion FlamesPresented at
Institute of Physics Combustion Physics
Group,Current Research in CombustionLoughborough
Conference Centre, 2005

• Presented by Robert M. Woolley
• E.R.R.I., S.P.E.M.E., University of Leeds
• Sponsored by EPSRC

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Presentation Outline

• Motivations for research
• Turbulence and combustion modelling
• CH4 / Air jet modelling
• Higher-order chemistry model
• Conclusions and future work

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Industrial Applications
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TheValue of CFD

• Economy
• Safety
• Environment

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Turbulence and Combustion Modelling

• Turbulence modelling
• k-e closure model
• Reynolds stress closure model
• Combustion modelling
• Transported Probability Density Function(PDF)
• Conditional Moment Closure(CMC)

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Turbulence and Combustion Modelling

• Turbulence modelling
• k-e closure model
• Reynolds stress closure model
• Combustion modelling
• Transported Probability Density Function(PDF)
• Conditional Moment Closure(CMC)

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Conditional Moment Closure

• I II III IV V

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Mathematical Modelling and Closure Hypothesis

• Conditional velocity

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• Conditional scalar dissipation
• Conditional species production rate

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CH4/Air Jets

• 2575 CH4Air
• d 7.20 mm
• Pilot 18.2 mm
• D u 49.6 m / s
• E u 74.4 m / s
• F u 99.2 m / s
• vis 67d

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CH4/Air Swirl Jet

• 12 CH4Air
• d 3.60 mm
• Swirl annulus 5.0 mm
• ujet 66.3 m / s
• uswirl 16.3 m / s
• wswirl 25.9 m / s
• S 1.59
• vis 64d

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D
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Higher-order CMC

• Simplified 2-step kinetics

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• System described by two progress variables
• Reaction progress rates defined as

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D
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D
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E
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E
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F
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F
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SMA2
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Conclusions

• Success in first-order modelling of turbulent
  non-premixed jet flames with no extinction
• Success in application of second-order
  methodologies
• Identification of areas for further development

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Under Development Future Work

• Scalar Dissipation Models
• Devaud and Bilger
• Transported Conditional Velocity
• Reynolds Stress Models
• Craft and Launder
• Lifted flames and other extinction phenomena