Abstract

This paper reports an evaluation of the prediction performance of the Eddy Dissipation Concept (EDC) model for modeling the combustion of syngas under Moderate to Intense Low-oxygen Dilution (MILD) applications. Although recent studies show that the EDC model can be successfully used for modeling MILD combustion, it has been reported that some modifications to the model are needed to improve its predictions. In this work, we focus our attention on the impact of the EDC model semi-empirical constants. Thus, we performed a computational fluid dynamics analysis to evaluate the responses of the model to different constant combinations in terms of accuracy of prediction with respect to experimental results from the literature. In this paper, experimental results were taken from studies that reported the use of jet-in-hot-coflow (JHC) burners. Additionally, an experimental study was also performed to collect temperature data along the reaction zone. The steady Navier-Stokes equations were solved using a finite volume formulation with RANS approach in a 2D axisymmetric computational domain, that corresponds to a JHC burner. To match the experimental setup, we considered different oxygen levels and fuel jet Reynolds number. On the other hand, due to the syngas composition, detail reaction mechanism DRM-19 was implemented to describe the oxidation process. The computational results were discussed considering species concentration (carbon-dioxide, carbon-monoxide, and hydroxide) and temperature profiles along the reaction zone for both, MILD and conventional non-premixed combustion. The results suggest that the default model settings work reasonably well when used in both configurations. However, it was observed that the EDC model tends to underestimate the reaction processes under highly diluted conditions regardless of the gaseous fuel composition. It was found that better predictons of temperature and species profiles can be obtained if the time constant is modified according to the fuel composition