An experimental and numerical study of MILD combustion in a Cyclonic burner

The implementation of MILD combustion systems is limited by a lack of fundamental insight into such combustion regime and therefore novel tools are indispensable compared to traditional combustion systems. In this context CFD simulations for the prediction of the burner behaviour and for design and optimization appears essential for a successful introduction of such concept in some industries. Detailed chemistry has to be included in fluid-dynamics simulations in order to account for the strong turbulence-chemistry interaction in the MILD regime. An effective strategy to overcome this aspect is represented by tabulated chemistry techniques. In particular the implementation of Flamelet Generated Manifold with IML tabulation seems to be a promising tools for MILD systems and therefore high fidelity and comprehensive experimental data are needed for the assessment of such model. The present study is framed in this context and it investigates the characteristics of MILD Combustion in a Cyclonic lab-scale burner that operates with high level of internal recirculation degrees induced by a cyclonic fluid-dynamic pattern obtained by the geometrical configuration of the reactor and of the feeding system. Experimental tests were realized varying the mixture composition. Detailed measurements of local mean temperatures and concentrations of gas species at the stack for several operating conditions were used to validate the FGM model under such unconventional operating conditions. Results suggest that FGM with IML is a promising tool for modeling the complex flame structures of cyclonic MILD burner, with many aspects that need to be further investigated.