Nozzle development [report]

F.T. Dodge, L.G. Dodge, J.E. Johnson
1989 unpublished
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 pre'ct the performance of the fuel nozzles independent of system application, lt is recognized that fuel nozzles or injectors must meet a number of criteria for proper system performance, and rather than
more » ... fine a single coefficient-of-performance, this report shows that it is more realistic to define the critical characteristics and recommend standard methods for the measurement of those characteristics. 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 included 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. ,.he surface tension from about 22 to 73 dyne/cm. In addition, tests were performed to characterize straight-tube gas-solid nozzles using two different size distributions of glass beads in air. The experimental results have been correlated in such a form that they may be used to predict the performance of nozzles of other sizes and at other conditions that those tested here. As a part of this program standardized procedures have been developed for processing measurements of spray drop-size characteristics and the overall cross-section average drop or particle sizes. These procedures result in average drop sizes that are more representative of the overall spray than measurements at a single location, and they allow comparison of measurements made by different instruments that sample the spray in different ways (e.g., line-of-sight integral , value or point measurement). The procedures are currently being incorporated by the American Society for Testing and Materials (ASTM) as part of the basis for a standardized spray test for laser-diffraction measurements of spray characteristics. In addition, spray measurements of diesel hole-type nozzles with a laser-diffraction particle sizer have shown the limitation of using standard laser beam diameters for these types of sprays. The improvement in spatial resolution associated with using a smaller (than standard) laser beam diameter has been demonstrated. b The improvements in experimental techniques and data processing algorithms and the experimental results for specific nozzle types and multi-phase fluids are believed to be of ,o considerable significance to the Fossil Energy Program at Morgantown Energy Technology Center. ." PREFACE
doi:10.2172/5432791 fatcat:yonyw6yae5hm5a6xtakr5toewy