Influence of Chemical Reaction Mechanisms on the Combustion Characteristics in a gas turbine model combustor

Document Type : Original Article

Authors

Iran University of Science & Technology

Abstract

The purpose of the present paper is to investigate the influence of different chemical mechanisms on non-premixed combustion of Kerosene liquid fuel in a gas turbine model combustor.Numerical simulations of two-phase reacting flow in this combustoris performed by Realizable k-ε turbulence model, Steady Laminar flamelet combustion model, and Discrete Ordinates radiation model in a structured finite volume mesh. An Eulerian-Lagrangian approach is applied to model droplet spray of liquid fuel. The results in the present paper are obtained using three different chemical reaction mechanisms for Kerosene and the boundary conditions in the three cases are based on the experimental conditions. Validation of the results are performed by comparing the velocity and temperature distributions with the avalible experimental data. Accordingly, the results obtained by the first chemical reaction mechanism, which consists of 17 species and 26 reactions, are more accurate and closer to the experimental data.Comparisons of the mean velocity and temperature distributions with available experimental data are one of the outputs of the present paper. Also, the quantity of scalar dissipation rate, mixture fraction, mass fraction and the rate of formation of carbon dioxide, water vapor, Kerosene and nitric oxide are compared for the three different chemical reaction mechanisms. The results show that because of differences in the decomposition rate of C12H23 and consumption rate of O2, average mixture fraction in the chemical mechanismsare different. In addition, the scalar dissipation rate of the flame is affected by the turbulent flow in the three mechanisms.Further,the concentration of produced NO and CO2in the flame region using the three mechanismsare differentdue to the flame temperature differences.

Keywords