An Effect of Dilution and Turbulence on Formation of MILD Combustion

An effect of dilution and turbulence on the formation of MILD combustion was numerically analyzed using kappa-epsilon (SKE) and Eddy Dissipation Concept (EDC) model appropriate to MILD combustion simulation. Results show that the temperature distribution of hydrogen and methane were similar under the condition of 3% diluted oxygen but the combustion reaction rate of hydrogen is increased as the flame temperature was about 80 degrees higher. This higher reaction rate tends to narrow MILD zone compared to methane case. As the dilution effect is increased and the dilution oxygen concentration becomes lower, the MILD area with Da<1 is shown to be wider with no significant difference. When the turbulence intensity is increased from 2.5% to 5%, the MILD region with Da<1 tends to be formed in a wider area, which is more favorable condition for hydrogen MILD combustion.