The objective of this program has been the development of experimental techniques and data processing procedures to allow for the characterization of multi-phase fuel nozzles using laboratory tests. Test results were to be used to produce a single value coefficient-of-performance that would predict the performance of the fuel nozzles independent of system application. Several different types of fuel nozzles capable of handling multi-phase fuels have been characterized for: (a) fuel flow rate versus delivery pressure, (b) fuel-air ratio throughout the fuel spray or plume and the effective cone angle of the injector, and (c) fuel drop- or particle-size distribution as a function of fluid properties. Fuel nozzles which have been characterized on both single-phase liquids and multi-phase liquid-solid slurries include a variable-film-thickness nozzle, a commercial coal-water slurry (CWS) nozzle, and four diesel injectors of different geometries (tested on single-phase fluids only). Multi-phase mixtures includes CWS with various coal loadings, surfactant concentrations, and stabilizer concentrations, as well as glass-bead water slurries with stabilizing additives. Single-phase fluids included glycerol-water mixtures to vary the viscosity over a range of 1 to 1500 cP, and alcohol-water mixtures to vary the surface tension from about 22 to 73 dyne/cm. In addition, tests were performed to characterize straight-tube gas-solid nozzles using two differences size distributions of glass beads in air. Standardized procedures have been developed for processing measurements of spray drop-size characteristics and the overall cross-section average drop or particle size. 43 refs., 60 figs., 7 tabs.