Validation of Turbulence/Chemistry Interaction Models for use in Oxygen Enhanced Combustion

In conventional air-fired combustion systems a huge amount of the heat of formation is absorbed by nitrogen. Oxygen enhanced combustion (OEC) systems uses an O2/N2 mixture with a higher concentration of oxygen than in the ambient air. As a consequence, higher flame temperatures as well as an improved radiative heat transfer in the furnace can be determined when OEC is used. Therefore, OEC is an option to increase the furnace efficiency especially in energy demanding high temperature processes like metal, glass or cement industries.

The investigated furnace is cylindrical shaped with 1 m in diameter and a length of 4 m. It was tested for air-fuel combustion and several OEC test cases. A two-staged natural gas burner was arranged at the front surface. The burner allows three different methods to supply the O2/N2 mixture (premixed, air/oxy-fuel, oxygen lancing). Furthermore, the furnace was surrounded by a water cooled shell where the measurement of the total heat flux to the furnace wall was performed. Additionally, in-flame temperatures were determined at several radial and axial distances. Measured results were used to validate the CFD simulations carried out with the eddy dissipation (EDM), eddy dissipation concept (EDC) and steady flamelet model (SFM).