Kathy Underhill-Shanks and M. Keith Hudson & Matthew J. Russo
ABSTRACT: The feasibility of using lead selenide (PbSe) detectors and simple electronic circuitry, including a 600 Hz chopper and chopper frequency/ phase reference circuit, to detect infrared emissions from flames and rocket motor plumes was demonstrated. A fixed wavelength radiometer, employing one-inch interference filters and mechanical phase adjustment, was constructed to monitor the 4.4-µm carbon dioxide band and the 2.7-µm water vapor band. The fixed wavelength radiometer was used in flame studies and in several rocket motor tests. The design of the fixed wavelength radiometer was modified to produce a spectroradiometer. The spectroradiometer system included a circular variable filter (CVF) having a wavelength range of 2.1 to 4.7-µm, which allowed wavelength scanning. The circuitry for the spectroradiometer was improved to include a time constant, which could be adjusted electronically, and an electronic phase adjustment. The spectroradiometer was used to monitor numerous rocket motor firings. The infrared emissions detected by the spectroradiometer included: the water vapor band at 2.7 µm, the hydrogen chloride band at 3.5 µm, and the carbon dioxide band at 4.4 µm.
Keywords: IR radiometer, rocket plume monitoring, PbSe detector, engine health, combustion diagnostics, infrared spectroscopy, IR emission
Ref: JPyro, Issue 12, 2000, pp57-67
(J12_57)
© Journal of Pyrotechnics and CarnDu Ltd
