Combustion Efficiency Measurements in a Rotating Detonation Engine Using Scanned-Wavelength-Modulation Spectroscopy
Published in AIAA SciTech Fourm, 2025
A tunable diode laser absorption spectroscopy (TDLAS) sensor using the scanned-wavelength-modulation spectroscopy (scanned-WMS) technique was used to measure temperature and H2O partial pressure at the exit throat of a hydrogen/air fueled rotating detonation engine (RDE) at a measurement rate of 1 MHz. DFB laser diodes were used to target near-infrared H2O transitions centered at 7185.596 cm^-1 and 6806.03 cm^-1. Both lasers were scanned across their respective transition at a rate of 500 kHz and were modulated at 36 MHz and 45 MHz respectively. Time histories of temperature and partial pressure were inferred from the WMS-2f/1f and -4f/2f harmonics signals. Combustion efficiency was then determined from the partial pressure time trace, a CTAP measurement, and a chemical balance model for the combustion of hydrogen with air. An inverse relationship is observed for combustion efficiency and equivalence ratio. Measurements are presented for two equivalence ratios, 0.6 and 0.8, both at an air mass flowrate of 0.3 kg/s.
Recommended citation: Guerrero, Jose, and Mirko Gamba. "Combustion Efficiency Measurements in a Rotating Detonation Engine Using Scanned-Wavelength-Modulation Spectroscopy." AIAA SCITECH 2025 Forum. 2025.
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