Influence of TRI on radiation source term during turbulent flame simulation

Sandia Flame D taken as an example, the influence of turbulence-radiation interaction(TRI) caused by temperature fluctuations on radiation source term was discussed. Based on the turbulence and combustion modeling with realizable κ-ε turbulence model, probability density function(PDF) model and detailed chemical mechanism, radiation heat transfer was simulated with P1 approximation and gray band approximation of narrow-band model. The correlation between fluctuations of absorption coefficient and those of Planck function was simulated using Reynolds decomposition, Taylor series expansion and solution to transport equations of temperature fluctuations. Optically thin fluctuation approximation(OTFA) was used simultaneously, which neglected the correlation between fluctuations of absorption coefficient and those of radiation intensity. The results show that thermal radiation increases due to TRI caused by temperature fluctuations. The computed results are close to the experimental data when TRI effect is considered in the simulation of thermal radiation source term. Therefore, TRI effect should be considered in the estimation of thermal radiation source term in turbulent jet flame simulation.