Correction: Simultaneous in-chamber MHz sensing of CO, H2O, temperature, and pressure via mid-infrared laser absorption in a rotating detonation rocket engine

A mid-infrared laser absorption sensing strategy for simultaneous measurement of carbon monoxide (CO), water (H2O), pressure, and temperature has been developed for in-chamber MHz rate measurements of gas dynamics in rotating detonating rocket engines (RDREs). Trapezoidal modulation via bias-tee circuitry integrated with two distributed feedback quantum cascade lasers provided sufficient scan depth to capture rovibrational transitions in the fundamental bands of CO and H2O (at 5 μm) with a time resolution of 1 μs. The two lasers are multiplexed into a single InF3 single-mode fiber for light delivery to the annulus of a methane-oxygen fueled RDRE at the Air Force Research Lab in Edwards, CA. This demonstration, utilizing a single detector, yields quantitative temperature, pressure, and two-species measurements at 1 MHz over a range of expected in-chamber post-detonation conditions, 1500–3000 K and 1–5 atm. The flow rate and equivalence ratios studied in this paper are relevant to the Air Force Research Laboratory’s Modeling Validation for Propulsion (MVP) efforts.