In this paper, turbulent non-premixed CH4+H2 jet flame issuing into a hot and
diluted co-flow air is studied numerically. This flame is under condition of
the moderate or intense low-oxygen dilution (MILD) combustion regime and
related to published experimental data. The modelling is carried out using
the EDC model to describe turbulence-chemistry interaction. The DRM-22
reduced mechanism and the GRI2.11 full mechanism are used to represent the
chemical reactions of H2/methane jet flame. The flame structure for various
O2 levels and jet Reynolds numbers are investigated. The results show that
the flame entrainment increases by a decrease in O2 concentration at air side
or jet Reynolds number. Local extinction is seen in the upstream and close to
the fuel injection nozzle at the shear layer. It leads to the higher flame
entertainment in MILD regime. The turbulence kinetic energy decay at centre
line of jet decreases by an increase in O2 concentration at hot Co-flow.
Also, increase in jet Reynolds or O2 level increases the mixing rate and rate
of reactions.
Modelling of MILD combustion in a lab-scale furnace with an extended FGM model including turbulence–radiation interaction