Numerical Study of the Effects of Oxygen Concentration and Fuel Jet Velocity on Thermal Radiation in Methane and Propane Turbulent Diffusion Flames

摘要

Thermal radiation is an important mode in combustion and plays a key role in improving energy efficiency and reducing the formation of pollutants in industrial combustion systems. This paper describes the effects of oxygen concentration and fuel (methane and propane) jet velocity on thermal radiation in turbulent diffusion flames via numerical evaluation, using a detailed gas-phase reaction mechanism consisting of 36 species and 219 elementary reactions with the discrete ordinates method. The predictions show close agreement with the experimental results in literature. Specifically, the radiative heat transfer flux and radiation fraction of propane flames were larger than those of methane flames at the same input power because of the increased soot yield in propane flames. In both methane and propane flames, thermal radiation generally increased with oxygen concentration, while at higher oxygen concentrations the degree of radiation increase was lower. Because of the promotion of soot oxidation at higher fuel velocities, the radiant fractions were lower than at lower fuel velocities.