Optical Diagnostics of High-Pressure Liquid Fuel Sprays

A report describes experiments in which nonintrusive optical diagnostic techniques were applied to high-pressure fuel sprays in simulated advanced turbine-engine combustor environments. The experiments involved three different fuel injectors in two unique optically accessible combustors: a radially-staged gas turbine combustor designed for testing multiple injectors and a flame tube designed for testing single injectors. Flows were observed at inlet temperatures from 533 to 810 K, inlet pressures from 0.55 to 1.7 MPa, and various mass flow rates. Planar laser-induced fluorescence and planar Mie scattering were used to image distributions of sprayed fuel, while phase Doppler particle analysis was performed to determine size and velocity distributions of fuel droplets. Analysis of the data thus acquired lead to the conclusions that (1) differences among spray patterns for different fuel injectors and operating conditions are readily observable and (2) fuel-spray angles can easily be measured under realistic conditions. This work clearly demonstrates utility of these nonintrusive optical techniques for investigating fuel-spray patterns in realistic turbine-engine combustor environments.