Chemical Kinetics and Reacting Flows

Chemical kinetics plays a crucial role in many high-temperature flows of engineering and scientific interest, particularly including combustion and propulsion systems. Despite significant progress in the fundamental theories associated with chemical kinetics, this field still relies very heavily on experimentation and shock tubes have become a primary source of fundamental and applied chemical kinetic data, and virtually the only source of data at temperatures above about 1500 K. Most shock tube kinetics experiments are conducted behind reflected shock waves, where the reacting gases are effectively stagnated and utilize either in situ optical diagnostics or sampling-based analysis via mass spectrometry or gas chromatography. Of particular value are laser-based measurements of species and temperature using absorption of light in quantum-specific atomic or molecular transitions, which combines both fast time resolution and high species specificity, including ability to monitor critical radical species. Here we present an overview of the state-of-the-art of shock tube methodologies for generating uniform, accurately known reaction conditions, and we discuss the range of laser absorption diagnostics now available for monitoring species time histories.