Basic research model of natural gas combustion in turbulent flow. Phase 2, Annual report, 1 August 1991-31 July 1992
The report describes progress made in the past twelve months in developing a local integral method (LIM) model for numerically simulating natural gas mixing and combustion in complex flames. The LIM model is fundamentally different from conventional approaches for numerically simulating combustion in turbulent flames. It is based on the experimental observation that the strain-diffusion balance which establishes the mixing and reaction scales in turbulent flames leads to a self-similar internal structure in the diffusion-reaction layers which does not need to be continually re-computed. Instead, these diffusion and reaction scales are represented by a set of self-similar profile shapes whose moments are allowed to evolve freely to satisfy the governing equations. The resulting LIM computations thus need only follow the evolution of material surface in the flow, and then solve ODE's (ordinary differential equations) on the surface, rather than PDE's (partial differential equations) throughout the whole flame. Results obtained to date show that the model is capable of correctly predicting even highly sensitive non-linear characteristics associated with the combustion processes in turbulent natural gas flames, including the local flame extinction phenomenon in large Zeldovich number Arrhenius kinetics. The simplicity of the LIM technique allows large reductions in computational time in comparison with traditional computational approaches, thus allowing far more complex reaction chemistry to be addressed, as well as ranges of Reynolds, Schmidt and Damkohler numbers which are otherwise completely inaccessible to simulation.
- Research Organization:
- Michigan Univ., Ann Arbor, MI (United States)
- OSTI ID:
- 6700771
- Report Number(s):
- PB-93-158509/XAB; CNN: GRI-5088-260-1692
- Resource Relation:
- Other Information: See also PB--92-190362
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
NATURAL GAS
COMBUSTION
TURBULENT FLOW
MATHEMATICAL MODELS
BENCH-SCALE EXPERIMENTS
CHEMISTRY
COMPARATIVE EVALUATIONS
DIFFERENTIAL EQUATIONS
DIFFUSION
EQUATIONS
FINITE DIFFERENCE METHOD
FLAMES
LAYERS
LEADING ABSTRACT
MIXING
PARTIAL DIFFERENTIAL EQUATIONS
REACTION KINETICS
REYNOLDS NUMBER
SIMULATION
VORTICES
ABSTRACTS
CALCULATION METHODS
CHEMICAL REACTIONS
DOCUMENT TYPES
ENERGY SOURCES
EVALUATION
FLUID FLOW
FLUIDS
FOSSIL FUELS
FUEL GAS
FUELS
GAS FUELS
GASES
ITERATIVE METHODS
KINETICS
NUMERICAL SOLUTION
OXIDATION
THERMOCHEMICAL PROCESSES
034000* - Natural Gas- Combustion