冲压发动机羽流温度TDLAS在线测量系统

In order to realize the online measurement of hydrocarbon fuel ramjet engine plume temperature, the spectral line pair of (7 444.352+7 444.371) cm^-1~(7 185.586 5+7 185.597 3) cm^-1 was optimally selected through molecular spectral simulation taking H₂O molecular as the target composition, and tunable diode laser absorption spectroscopy (TDLAS) system was designed to measure the parameters of hydrocarbon fuel ramjet engine plume using scanned-wavelength direct absorption spectroscopy-time division multiplexing (SDAS-TDM) strategy. Moreover, the temperature measurement accuracy of this system was verified by premixed flat-flamed burner. The results show that the relative deviations between the measured flame temperature at the height of 1cm of the premixed flat-flamed burner using this system and the standard reference value are all within 15%. On this basis, the system was applied to measure the parameters of the hydrocarbon fuel ramjet engine plume. Through alternately modulating of 1 392 nm and 1 343 nm diode lasers, the intensity attenuation signal of the modulated laser passing through the measuring zone was measured, the H₂O molecule absorption spectrums at (7 444.352+7 444.371) cm^-1 and (7 185.586 5+7 185.597 3) cm^-1 lines were obtained. The online temperature measurement of the hydrocarbon fuel ramjet engine plume was realized with two-line technique, which provides important references for the combustion organization and performance evaluation of hydrocarbon fuel ramjet engine.