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Experimental Methodology for Estimation of Local Heat Fluxes and Burning Rates in Steady Laminar Boundary Layer Diffusion Flames
Published on: June 1, 2016
Transition between an exothermic chemical wave front and a generic flame
G Dumazer1, M Leda, B Nowakowski
1CNRS, Laboratoire de Physique Théorique de la Matière Condensée, Université Pierre et Marie Curie, UMR 7600, 4 place Jussieu, Case Courrier 121, 75005 Paris, France.
Physical Review. E, Statistical, Nonlinear, and Soft Matter Physics
|September 4, 2008
Summary
This study investigates exothermic chemical wave fronts, revealing a critical transition point. Beyond this point, flame speed is dictated by heat release, not chemical dynamics, validating macroscopic combustion models.
Area of Science:
- Chemical kinetics and thermodynamics
- Fluid dynamics and heat transfer
- Combustion science
Background:
- Exothermic chemical wave fronts are crucial in combustion processes.
- Understanding the transition between chemical fronts and generic flames is essential for accurate modeling.
- Existing macroscopic approaches often simplify complex chemical reaction mechanisms.
Purpose of the Study:
- To investigate the behavior of exothermic chemical wave fronts under varying reaction heat.
- To identify the critical conditions leading to a transition in wave front dynamics.
- To derive an analytical expression for flame speed based on hydrodynamic invariants.
Main Methods:
- Numerical solution of hydrodynamic equations for stream velocity, temperature, and concentrations.
- Systematic variation of reaction heat to observe changes in wave front propagation.
- Derivation of an analytical expression for flame speed using conserved quantities.
Main Results:
- A critical value of heat release was identified, marking a transition in wave front behavior.
- Below the critical value, chemical front speed depends on chemical dynamics.
- Above the critical value, flame speed is solely determined by heat release, independent of chemical details.
Conclusions:
- The study confirms a distinct transition in exothermic wave front propagation based on heat release.
- An analytical expression for flame speed was derived, supporting macroscopic combustion models.
- The findings validate the use of simplified reaction mechanisms in macroscopic combustion modeling.
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