Time-resolved, single-ended laser absorption thermometry and H2O, CO2, and CO speciation in a H2/C2H4-fueled rotating detonation engine

Rotating detonation engines (RDEs) require novel diagnostic tools to better understand complex detonation behavior and improve performance. To this end, a single-ended laser absorption sensor for in situ , time-resolved measurements of temperature, H2O, CO2, and CO concentrations has been developed and deployed within the annulus of a hydrogen/ethylene/air-fed RDE. With a measurement rate of 44 kS/s, the sensor delivers four co-aligned, mid-infrared laser beams into the annular detonation chamber and captures the back-reflected radiation through a single optical port. A ray-tracing optimization algorithm, designed to maximize signal-to-noise ratio and beam-perturbation tolerance, was used to determine the optimal sensor optical configuration. Wavelength-modulation spectroscopy (WMS) further compensated for interference sources in the harsh detonation environment. Time-resolved and time-averaged sensor measurements of gas temperature and species at equivalence ratios of 0.74, 0.87, and 1.03 are presented. (C) 2020 The Combustion Institute. Published by Elsevier Inc. All rights reserved.

Automated summary

Rotating detonation engines (RDEs) require novel diagnostic tools for better understanding complex detonation behavior and improving performance. A single-ended laser absorption sensor has been developed and deployed for in situ, time-resolved measurements of temperature and gas species concentrations in the annulus of a hydrogen/ethylene/air-fed RDE. With a measurement rate of 44 kS/s, the sensor can provide high-quality data for gas temperature and species.