EXPERIMENTAL AND NUMERICAL ANALYSIS OF SPRAY DISPERSION AND EVAPORATION IN A COMBUSTION CHAMBER

This work investigates a set of two-phase flow submodels to propose a reliable complete numerical model that is able to predict flow and evaporating droplet properties under industrial gas turbine conditions. For these purposes, a confined complex spray configuration was studied experimentally and numerically. Measurements of the gas phase were conducted using the laser Doppler anemometry (LDA) technique. The nozzle was operated in a modular combustor at elevated pressure and temperature conditions. For the dispersed phase, a nonreacting phase (water) was chosen to prevent chemical reactions. The focus of the investigation was on spray propagation and evaporation. Droplet velocity components and droplet diameters were measured using phase Doppler anemometry (PDA). Radial profiles were taken along two axes, recording the axial and radial velocity components as well as the probability density functions of the diameter distributions. Numerical simulations were performed within the framework of a Reynolds-averaged Navier-Stokes (RANS)-based Eulerian-Lagrangian approach to appraise the prediction techniques used. Under the framework of two-way coupling, the dispersed phase effects on the momentum, turbulence quantities, energy, and mass were accounted for by adding appropriate source terms to each transport equation of the gas phase. A significantly large droplet number was used to ensure reliable statistical averaging so that the dispersed phase properties do not depend on the parcel number within the control volume. Comparisons between the numerical and experimental results showed acceptable agreement for the droplet velocities, axial mass flux, and Sauter mean diameter but some disagreements were observed for the fluctuations and the apex angle of the spray.