Investigation of soot formation and agglomeration in ethylene/air jet diffusion flame with rank correlated SLW model

Effect of radiation transfer is significant part of the overall heat transfer mechanism in sooting flames. The interaction between radiation transfer and soot formation considerably affects the combustion regime and the system efficiency. Spectral radiation models that account for the radiative effects of sooting flames need to be explored in detail to understand this phenomenon. This study numerically investigates the interaction between the radiation and soot formation in a sooting jet diffusion flame. In this regard, a rank correlated spectral linebased weighted sum of gray gases (RC-SLW) global model is implemented in Ansys Fluent and used for the radiation modeling of a jet diffusion flame and results were compared with the domain-based single gray gas weighted sum of gray gases (WSGG) model in Ansys Fluent RC-SLW model, including ethylene and acetylene flame radiation, showing considerable improvement in predicting the soot volume fraction compared to the domain-based single gray gas weighted sum of gray gases (WSGG) model available in Ansys Fluent. Increasing the number of gray gas bins in the RC-SLW model from 5 to 22 reduces the error in the maximum soot volume fraction from 30 % to 1 %. It was found that the effect of ethylene and acetylene radiation in the RC-SLW model has a minor effect on soot formation. Simulations without the effect of ethylene and acetylene radiation in the RC-SLW model underpredict the maximum soot volume fraction by 5 %. In addition, the effect of different possibilities of agglomeration of soot particles on the generated soot volume fraction was also investigated. Results showed that change of absorption coefficient due to change of soot agglomeration size affects maximum soot volume fraction by 6 %.