NUMERICAL STUDY OF TWO PHASE FLOW IN THE NEAR-NOZZLE REGION OF GAS TURBINE COMBUSTORS

In the present study flow conditions in the near nozzle region of the combustion chamber have been investigated. There exists two-phase flow in this region. The overall performance and pollutant formation in the combustion zone largely depends on the spray field in the near nozzle region. The studies are conducted to determine the effects of multijets on the flow pattern in the near nozzle region. The Phase Doppler Particle Analyzer (PDPA) has been used to measure the velocities and sizes of the droplets. The flow field of two-phase liquid drop-air jets is formed from three injectors arranged in t line. Furthermore the two-phase flow field has been analyzed numerically also. The numerical analysis consists of two computational models, namely, (i) 3 non-evaporating two-phase jets, (ii) 3 evaporating two phase jets. The Eulerian-Eulerian approach is incorporated in both the numerical models. Since the flow is turbulent, a two-equation model (k-ε) is implemented in the numerical analysis. Numerical solution of the conservation equation is obtained using PHOENICS computer code. Boundary conditions are provided from the experimental measurements. Numerical domain for the two models of the analysis start at some distance (about 10 diameters of the injector orifice) where the atomization process is completed and droplet size and velocity could be measured experimentally.Three air blast atomized two-phase jets of Jet-A fuel and air, for which the experiments have been conducted, are employed in the numerical study. The numerical and experimental results are compared and the agreement between them is found good