Eulerian–Lagrangian RANS Model Simulations of the NIST Turbulent Methanol Spray Flame

A methanol spray flame in a combustion chamber of the NIST was simulated using an Eulerian–Lagrangian RANS model. Experimental data and previous numerical investigations by other researchers on this flame were analyzed to develop methods for more comprehensive model validation. The inlet boundary conditions of the spray were generated using semi-empirical models representing atomization, collision, coalescence, and secondary breakup. Experimental information on the trajectory of the spray was used to optimize the parameters of the pressure-swirl atomizer model. The standard k-ϵ turbulence model was used with enhanced wall treatment. A detailed reaction mechanism of gaseous combustion of methanol was used in the frame of the steady laminar flamelet model. The radiative transfer equations were solved using the discrete ordinates method. In general, the predicted mean velocity components of the gaseous flow and the droplets, the droplet number density, and the Sauter mean diameter (SMD) of the droplets at various heights in the present study show good agreement with the experimental data. Special attention is paid to the relative merits of the employed method to set inlet boundary conditions compared to the alternative method of using a measured droplet size and velocity distribution.