An experimental and numerical characterization of a macrolaminate pressure atomizer, placed perpendicularly to a high-velocity, turbulent air stream, is presented in this work. The purpose of the study was to compare detailed spray measurements with computations using a commercial CFD code. This study was part of the development of the premixing section of a midsize gas turbine, redesigned to meet low emissions and dual fuel market requirements. First, the spray characteristics were determined by injecting into a quiescent environment at ambient conditions. This data provided input for CFD calculations. Then the fuel injector was placed in a test section, at ambient conditions as well, that simulated the cross flow position of the atomizer in the prototype combustor. Droplet size and velocity were measured downstream of the injector nozzle, using a one-dimensional Phase Doppler Particle Analyzer. Measurements were done in two measuring planes. Flow field measurements were made to establish a common base for the computations. 2D computations were made of these experiments, using a k-ε turbulence model. The droplet trajectories were calculated with a Lagrangian ‘random walk’ technique, including drop break-up. The computed droplet size and velocity show agreement with the measurements. Drop break-up was also well represented by the model. The computed dispersion of the injected mass is not in agreement with the measured profile. This discrepancy in droplet dispersion is possibly due to high turbulence levels in the flow field, which were not well captured in the model.
315 Effects of Number of Blades on Performance and Flow Field of an Undershot Cross-Flow Water Turbine