X-Ray Tomography and Structured Light Topography of 4-D Fuel Mass Distributions in Rocket Sprays

ABSTRACT: The primary objective of this research effort is to develop a next-generation X-ray tomography and surface topography imaging system for four-dimensional (4-D) characterization of liquid mass distributions within dense fuel sprays. This will be accomplished through high-speed 3-D imaging, providing information on both temporal and spatial variations of fuel mass distribution. The overall technical objectives of the research program are to (1) resolve the three-dimensional (3-D) liquid breakup process in dense sprays using X-ray radiography with multiple lines of sight and discrete tomographic reconstruction, (2) capture two or more 3-D X-ray images at rates of 10 kHz or greater, (3) minimize uncertainties due to changes in X-ray energy distribution along the absorption path, (4) enable studies of practical fuels with high soot loading, high temperatures, and high pressures, and (5) capture breakup dynamics of liquid-core and liquid-sheet structures by mapping 3-D liquid-surface topologies at 10 kHz or greater using structured light imaging. The proposed diagnostic systems will be optimized for image contrast over a wide range of optical densities to cover both gas-centered swirl coaxial and impinging-jet rocket sprays, which should also cover a wide range of applications in propulsion, including gas-turbine, augmentor, and scramjet combustion systems. BENEFIT: We anticipate that four-dimensional (4-D) X-ray tomography and surface mapping will provide new measurement capabilities for studying liquid-breakup dynamics in a variety of propulsion systems, including rockets, augmentors, gas turbines, and scramjets. This will enable improved fundamental understanding and modeling of dense sprays, which is of significant practical and scientific interest. The data provided by the proposed research program will enable propulsion engineers to design and optimize liquid rocket injectors to improve stability, performance, and maintainability. The understanding developed from the proposed tomography system is critical for improving the speed and efficiency of the design process, ultimately helping to avoid and or solve problems associated combustion dynamics brought on by transient, non-uniform fuel-air mixture preparation. This measurement capability is applicable for military and commercial propulsion systems, as well as industrial furnaces and internal combustion engines, leading to significant commercial applications.