- Author
-
Simpson, R.
- Title
- Turbulent Shear Flow.
- Coporate
- Virginia Polytechnic Institute and State Univ.
- Report
-
AOE 5154
date unknown
221 p.
- Keywords
-
turbulent flow
|
turbulent flames
|
laminar flames
|
soot
|
temperature
|
statistics
|
diffusion flames
|
acetylene
|
ehylene
|
propylene
|
propane
- Abstract
- Radiation from turbulent flames is an important heat transfer mechanism in many applications. In natural fIres, radiant transport influences the rate of burning of objects on fire, the rate of spreading of the fIfe to nearby combustible substances and the rate of heating of surrounding structures (deRis, 1979; Markstein, 1977). In gas turbine engines, radiative heat transfer to the engine liners results in frequent maintenance expenses and expensive liner cooling techniques (Lefebvre, 1983). Although significant progress has been made in the analysis of gas band radiation from nonluminous flames (Gore, 1986; Faeth et al., 1988a), substantial gaps exist in the understanding of continuum radiation properties from luminous flames. Motivated by these observations, the overall objective of the present investigation was to study the radiation properties of luminous (sooting) diffusion flames. The study concentrated on axisymmetric diffusion flames formed by injecting hydrocarbon fuels vertically upward from circular burners into ambient air. The continuum radiation properties of luminous flames depends on the local soot volume fraction and temperatures in these flames. The main research issues addressed here are 1) generalized gas species state relationships in hydrocarbon flames, 2) soot volume fraction state relationships, 3) continuum radiation properties and 4) turbulence/radiation interactions in buoyant turbulent luminous diffusion flames. The present investigation evaluated the laminar flamelet concept for soot volume fractions for four fuels - acetylene, propylene, ethylene and propane - burning in air; and its use in the prediction of continuum radiation properties in luminous flames. In addition, a methodology for computing local temperatures; in order to compute radiation properties, was also examined by generalizing state relationships for major gas species in hydrocarbon diffusion flames.