| Most of the combustion and propulsion applications are designed such that fuel and oxidizer are injected independently, mostly with multi-hole nozzles, into the chamber where it is mixed by turbulent diffusion and could achieve higher flame stability and fire protection. In non-premixed flames in a confined chamber, detailed modeling of flame wall interactions is crucial in predicting local heat release rates, flame quenching, and flame propagation and extinction. Wall thermal boundary conditions are pivotal in influencing combustion and flame propagation. In recent years, there have been many studies studying the effects of boundary conditions on flame propagation using a fully-compressible Navier-Stokes solver with different thermal conditions such as adiabatic and isothermal walls with various Lewis numbers and the Reynolds number correlated with the flame propagation. It is apparent that there is a necessity to determine the prediction of flame structure of a flame using Large Eddy Simulation (LES) and flame interaction with fluid motion and boundary conditions considering the importance of combustion. Flamelet/progress variable approach was applied to the large eddy simulation of a diffusion flame in a confined channel to flame propagation, calculate mixture variable and scalar dissipation rate in the CFD solver and update species concentration from the tabulated data. The OpenFOAM C++ platform that solves the transport equation of mass, energy, momentum, and species is used to explore and investigate the effects of wall thermal boundary conditions of a turbulent piloted methane/air diffusion flame in a confined channel configuration. It evaluates velocity and temperature profile during the flame progression along with the mixture fraction and intermediate chemical formations in an effective manner. As the flow passes through the concentric nozzle, the flow develops from a transition region to a flame propagation region and the flame wall interaction takes place. The model was applied to validate the experimental results of the Cambridge-Sandia burner. The approach at the lower fuel velocities have shown the accurate predictions and well reproduced results. Also, the attention is equally shifted to identify the smallest Damkohler number which basically represents the weakest burning intensity of the flame by the use of diffusion flame in order to see the effects of controlling parameters on flame propagation. Additionally, parametric studies were performed with different fuel flow rates in order to evaluate the minimum Damkohler number for the optimum steady burning in a constant geometry and study how the flame propagation varies with the fluctuation of the Damkohler number. |