Development of an Advanced Fluid Mechanics Measurement Facility for Flame Studies of Neat Fuels, Jet Fuels, and their Surrogates

摘要

Under this award the fluid mechanics measurement capabilities of the combustion and fuels laboratory of the University of Southern California were upgraded notably. Thus, the needs for determining flame properties of fundamental and practical importance can be met readily. The experimental data so obtained will be used for the validation of chemical kinetic and diffusion models for hydrocarbon fuels used in air-breathing devices that are of interest to the Air Force; furthermore, the data contain important information related to the performance of various practical fuels and will be useful in defining the operational range of advanced propulsion systems, such as scramjets. The acquired instrumentation involves high-resolution, high accuracy laser-based systems and subsystems and constitutes a major improvement of current capabilities in the principal investigator's (PI's) laboratory. This improvement enhances the quality of ongoing research that is conducted under AFOSR support significantly. Three state-of- the-art velocity measurement systems were developed to complement an existing digital particle image velocimetry (DPIV) system that was acquired previously under AFOSR support. The first velocity measurement system is a compact laser Doppler velocimeter (LDV). The other two are DPIV systems, which were developed around a high-power YAG laser that is available to the PI at no cost to AFOSR. After determining the velocity fields in flames, fundamental flame properties can be derived, such as laminar flame speeds, as well as ignition and extinction limits. The sensitivity of those properties to both chemical kinetics and molecular transport can be large, so that validation and/or optimization of various models can be achieved. The parameter space of the PI's ongoing research is extensive, as it involves a large number of fuels, such as neat hydrocarbons, jet fuels and their surrogates, fuel-air ratios, initial reactant temperatures, and thermodynamic pressures.