Modeling Effects of Soot and Turbulence-Radiation Coupling on Radiative Transfer in Turbulent Gaseous Combustion

ABSTRACT

A three-dimensional combustion model which couples turbulent flow statistics with chemical reactions and radiative heat transfer is used to evaluate the effect of soot and turbulence-radiation coupling on radiative transfer in an industrial-scale furnace. Radiation and soot formation models are presented which include the nonlinear dependencies between fluid turbulence effects, soot formation and radiative absorption and emission in the participating medium. The discrete-ordinates method is used to solve the radiation intensity field. Soot formation is predicted with a formation-destruction model based on local volatile content and stoichiometry. The impact of soot and turbulence-radiation coupling was evaluated based on incident surface fluxes and centerline temperature and emission. Result trends were as expected, but suggest that the magnitude of soot effects on radiative transfer may be less than originally thought for the type of furnace and operating conditions modeled in this research. Predicted local soot properties were significantly different when calculated with and without turbulence coupling. Emissive powers and incident wall fluxes were notably higher when nonlinear turbulence effects were not properly accounted for.

Key Words:

• Radiation
• soot
• combustion
• modeling