Numerical Investigation of Reacting Flow in a Double-swirled Gas Turbine Model Combustor

In this work, numerical investigation of a double-swirled gas turbine model combustor (GTMC) was carried out using RANS approach with three different turbulence models of RNG k-e, Realizable k-e and RSM, and two different turbulence-chemistry interaction models of EDC (Eddy Dissipation Concept) and TPDF (Transported Probability Density Function). A detailed reduced mechanism of DRM22 (with 22 species and 104 reactions) was used to represent the chemical reactions. GTMC with a good optical access for laser measurements provided a useful database for swirling CH4/Air diffusion flames at atmospheric pressure. Comprehensive comparisons were done for the predictions and measurements of velocity, mixture fraction, temperature, and chemical species concentrations of H2O2 O2O2OH,OHH2O,H2O CH4,CH4COCO,and CO2 Results showed an acceptable accuracy of predictions. This means that the simplified 2D-axisymmetric simulation has the ability to capture the important features and structure of combustion field in a double highly swirled chamber, like GTMC, with much lower CPU time in comparison with the costly 3D simulations. This study illustrated that using RSM turbulence model presents acceptable results for the flow field, while the other turbulence models were not capable of capturing quantitively acceptable results. In terms of comparison between the turbulence-chemistry interaction models, TPDF led to a good prediction for major species and flame structure near the inlets, while the EDC predicted more accurately downstream of the flow field. Morever, the analysis of flame structure showed that mixing of fuel and oxidizer under double-swirl configuration happens fast and in high levels. In addition, using this type of mixing led to stabilization of main reaction zone in the center of combustion chamber near the injection plane. As a result, under double-swirl injection configuration clean and high quality combustion with reduced size of combustion chamber can be achieved simultaneously.