Simulation of Non-premixed Turbulent Natural Gas Combustion in Delft-Jet-in-Hot-Coflow Burner

Delft-Jet-in-Hot-Coflow burner can operate Moderate and intense low oxygen dilution (MILD) combustion which yields high thermal efficiency and low fuel consumption along with less pollutant's emission. This study includes a numerical CFD simulation investigation of non-premixed turbulent combustion for a jet of Dutch natural gas with a lean combustion hot and dilutes co-flow that products in the Delft-Jet-in-Hot-Coflow (DJHC) burner and to mimic Moderate and Intense Low Oxygen Dilution (MILD) characteristics. The simulation has been conducted to measure lift-off height, velocity and temperature of Dutch natural gas (DNG) combustion in the Delft Jet-in-Hot-Coflow (DJHC) burner for two different fuel jet Reynolds numbers (i.e. Re=4100 and Re=8800). The CFD numerical simulations are performed through solving Reynolds-averaged Navier Stokes equations (RANS) equations where standard k-epsilon (SKE) model has been used as a turbulent model in combustion along with two different turbulent-chemistry interaction models of Eddy Dissipation Concept (EDC) and transported probability density function (PDF). The two-step global kinetic mechanism of methane and air (methane-air 2 step mechanism) is applied as chemical kinetics with the EDC model and on other hand Flamelet Generated Manifold (FGM) is applied in the Probability Density Function (PDF). The simulations results are associated with existing experimental data for understanding better CFD performance to simulation turbulent combustion. The simulation results for both models also yield similar prediction with experimental observation in trend of decrease in lift-off height with higher Reynolds jet.