Numerical Study of Methane/Hydrogen Flame Structure at MILD Condition

Environmental pollution and daily increase of greenhouse gases in one hand, and adverse effects of them on human health and climate changing on the other hand, show the importance of using suitable methods for combusting fossil fuels with high efficiency and low emissions. Technology of Moderate and Intense Low oxygen Dilution (MILD) combustion improves combustion efficiency and reduces environmental pollutants. In this research, numerical application of different reduced chemical mechanisms and combustion models for simulating Methane-Hydrogen flame at MILD combustion condition were studied and effect of co-flow oxidant concentration and mass flow on adiabatic flame temperature and pollutants concentrations were investigated. Modelling has been done for 3, 6 and 9 oxygen mass fractions in hot co-flow. Results show that maximum flame temperature and emissions concentrations are increased by oxygen mass fraction increment. Investigations reveal that rise of mass flow of hot co-flow decreases flame thickness and adiabatic flame temperature. Numerical predictions at axial distances near to fuel nozzle are more accurate than downstream locations and using PaSR combustion model and KEE-58 reduced chemical mechanism have better agreement with experimental data than EDC and PDF combustion models and DRM-19 reduced chemical mechanism.

Keywords:

MILD combustion , Methane/Hydrogen fuel , PaSR combustion model