Experimental Investigation of Jet-A and Single-Hydrocarbon Fuel Sprays at Engine-Relevant Conditions

Fuel atomization and air-fuel mixing are critical processes that directly influence the efficiency, performance, and emissions of propulsion systems. Achieving next-generation design goals, such as reduced emissions, improved fuel economy, and enhanced combustion stability, requires a detailed understanding of spray dynamics under engine-relevant conditions. This study applies high-speed optical diagnostics to fuel sprays injected into a constant volume combustion chamber (CVCC) under various engine operating conditions. Through high-speed extinction and schlieren imaging, this work characterizes the spatial and temporal development of both liquid and vapor phases across multiple fuels and ambient conditions. For further analysis of the spray structure, proper orthogonal decomposition (POD) is used to extract insights into coherent structures in the near-injector region. This decomposition reveals repeatable, high-variance flow patterns along the liquid spray boundary. By integrating experimental insight with reduced-order information, this work supports the development of more efficient and cleaner aerospace propulsion technologies, offering a foundation for improved design, simulation, and optimization of fuel injection and combustion processes.