Local Extinction Mechanisms in Non-Premixed Turbulent Combustion
Abstract
The goal of this research was a quantitative understanding of turbulence-chemistry interactions pertinent to future aeropropulsion combustors. For example, (1) flameout and relight in turbine combustors are related to interactions of turbulence with chain-branching reactions; (2) hydrogen burnout in supersonic combustors is related to interactions with recombination reactions; and (3) emissions of NOx, CO, smoke and other observables are related to nonequilibrium in the populations of intermediate species such as oxyhydrogen radicals and C(x)HCy). A bluff-body stabilized turbulent diffusion flame, time- and space-resolved lase Raman measurements of major species, and a nonequilibrium computational fluid mechanics code were applied to the problem. Principal conclusions include: (1) Turbulent jet flames are being abandoned in the search for more intensely turbulent flames. (2) An axisymmetric bluff-body stabilized turbulent diffusion flame burner is a reasonable choice for combustion research at high Reynolds numbers, approaching blowoff. (3) Raman scattering for measurements of major species and temperature can be extended into the sooting/chemiluminescent environment of methane flames. Space- and time-resolved Raman scattering measurements were made in bluff-body stabilized CO/H2/N2 and CH4 flames at conditions approaching blowoff. (4) A thermochemical submodel based on partial equilibrium in the oxyhydrogen radical pool was developed for the 27.5% CO/32.3% H2/40.2% N2-air system. The chemistry can be described in terms of two scalars. The elliptic form of the time-averaged Navier Stokes equations with k-epsilon closure was solved using an iterative finite- volume/pressure-correction algorithm.
Document Details
- Document Type
- Technical Report
- Publication Date
- Aug 31, 1991
- Accession Number
- ADA242027
Entities
People
- A. Gulati
- S. M. Correa
Organizations
- General Electric