Broadband Infrared Absorption Sensor for High-Pressure Combustor Control

A sensor approach for monitoring temperature uniformity, and also integrated water mole fraction, in the exit planeof a high-pressuregas turbine combustor is presented. The sensor, intended foruse in anactive control system, is based on infrared line-of-sight absorption measurements of water with a relatively broadband light source. Performance of the sensor was simulated using a computer model based on the HITRAN/HITEMP database for the infrared absorption of water. SpeciŽ c regions of interest near 2.5 μm were identiŽ ed, based on their relative sensitivity to temperature. One region is relatively insensitive to temperature and permitsmonitoringof integrated water mole fraction across the exhaust. Two wavelengths, onewith positive slope sensitivity and the other negative, are used to monitor the uniformity of the exhaust temperature proŽ le. The linearity and sensitivity of the approach to uncertainties in the spectral shape and width, as well as the wavelength of the Ž ltered light source, are also presented.