THE FLOW INSIDE A MODEL GAS-TURBINE COMBUSTOR - CALCULATIONS

The present study assesses the ability of the k-epsilon turbulence mod el to calculate the flow inside gas turbine combustors. Results of cal culations using a cylindrical system of coordinates, hybrid differenci ng, and a mesh with about 40,000 nodes are compared with velocity meas urements of the flow inside a perspex model of can-type gas turbine co mbustor. The larger discrepancies between measurements and predictions were found in the primary region. The complexity of the flow near the primary jet impingement led to underprediction of the maximum negativ e axial velocity and turbulence kinetic energy by about 35 and 20 perc ent, respectively. The calculated results exhibited higher levels of m omentum diffusion compared to the experiments and did not show the two contrarotating vortices created between the primary jets; no qualitat ive agreement with the azimuthal velocity downstream of the primary je ts could be achieved. Despite these deficiencies, the model gave accep table results in other regions of the combustor and correct prediction of the main features of the combustor flow was possible.