FASPEC-Fast Adaptive Spectrometer Programmable for the Evaluation of Combustion

Emerging scramjet technology has enormous potential for the development of small hypersonic aircraft and spacecraft, with numerous military and civilian applications. Spectral Sciences, Inc. proposes to develop a novel, high-speed, adaptive spectral imaging sensor for use as a research and development tool for monitoring combustion progress and temperature in the scramjet flow channel and exit plane. The sensor will measure temporally and spectrally resolved thermal radiance from combustion products (water and hydroxyl radical) over multiple lines of sight. By measuring different parts of the spectrum as a function of time, time-resolved gas temperature and water and hydroxyl concentrations will be retrieved. This passive, non-intrusive approach is ideally suited to the demanding hypersonic shock tunnel test environment, which is characterized by a very short experiment duration (time scale of milliseconds), limited optical access, and inhomogeneous fluid densities. The instrument features a robust, high-throughput design combining optical fibers with dynamically programmable dispersive optics containing no macroscopic moving parts. The spectral and spatial resolution are controlled through software, and the bandpasses can be digitally shaped to cancel interfering background radiation. This versatility should make the instrument applicable and cost effective for a wide variety of high-speed spectral applications.