CFD simulation of confined non-premixed jet flames in rotary kilns for gaseous fuels

In the present study, computational fluid dynamics (CFD) methodology is used to investigate the confined non-premixed jet flames in rotary kilns. Simulations are performed using ANSYS-Fluent, a commercial CFD package. A two-dimensional axisymmetric model is conducted to understand the main operational and geometrical parameters of rotary kilns, which affect the flame behaviors, including the aerodynamics and heat transfer. Three kinds of fuels are employed in this study; Methane (CH4), Carbon Monoxide (CO) and Biogas (50% CH4 and 50% CO2). Confined jet flame length correlations are developed and presented in terms of kiln operational and geometrical parameters. Previous 2-D simulation results of free jet flames are used to select and validate the turbulence model, which applied in this study. The present simulation results are compared with available experimental data and previous analytical results, which show satisfactory agreement.