Highly flexible burner concept for research on combustion technologies with recirculation of hot combustion products

This paper reports the development and testing of a research coflow burner that generates laminar flames in a hot and diluted environment, which is adequate for studying the operating conditions found in practical combustors that use flue gas recirculation techniques. The burner has two flame zones; the first is an annular laminar premixed flat flame stabilized by a perforated plate, which generates a hot oxygen-rich flue gas mixture. The second is a non-premixed laminar flame, which uses the hot oxygen-rich flue gas mixture as an oxidizer. A methodology based on coflow calculations, which is the most significant component, was designed to provide different temperatures and dilution levels. The burner was built based on this design and tested using both intrusive and non-intrusive measurement techniques. The device emulated several features of practical combustor systems but with a simpler geometry, well-defined boundary conditions and using the simplest configuration found in literature (laminar flames). In a preliminary study, the MILD combustion regime was emulated by generating methane laminar non-premixed flames at oxygen concentrations between 3% and 9% and temperatures between 973 K and 1173 K.