Models Evaluations of Combustion Process in a Cylindrical Furnace

Abstract

In this work an evaluation of different combustion models for predicting oxygen enriched combustion processes was performed. Two types of models were selected. The first one was a generalized finite rate model, in which the conservation equation for the mass concentration was solved, for all species present in the process. In this modeling approach, three different reaction rate expressions were considered. The second case was based on the PDF formulation, which consisted in solving the conservation equations for the mass fraction and its variance. In this second approach the species distributions were determined by assuming two different shapes for the probability density functions. The mass, momentum, energy and species or mass fraction conservation equations were numerically solved by a finite volume formulation. The two-equation κ-ε turbulence model was selected for solving the turbulent problem. Radiation was taken into account by the discrete transfer radiation model. After solution, the temperature and species concentration fields were compared with available experimental data. Although the PDF formulation involved the solution of a smaller number of equations, therefore consuming less computer time, the performance of the generalized finite rate model was superior in the present test cases.