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Visible chemiluminescence of ammonia premixed flames and its application for flame diagnostics

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  • معلومة اضافية
    • Contributors:
      Lund University, Faculty of Science, Department of Physics, Combustion Physics, Lunds universitet, Naturvetenskapliga fakulteten, Fysiska institutionen, Förbränningsfysik, Originator; Lund University, Profile areas and other strong research environments, Lund University Profile areas, LU Profile Area: Light and Materials, Lunds universitet, Profilområden och andra starka forskningsmiljöer, Lunds universitets profilområden, LU profilområde: Ljus och material, Originator; Lund University, Faculty of Engineering, LTH, LTH Profile areas, LTH Profile Area: The Energy Transition, Lunds universitet, Lunds Tekniska Högskola, LTH profilområden, LTH profilområde: Energiomställningen, Originator; Lund University, Faculty of Engineering, LTH, LTH Profile areas, LTH Profile Area: Photon Science and Technology, Lunds universitet, Lunds Tekniska Högskola, LTH profilområden, LTH profilområde: Avancerade ljuskällor, Originator; Lund University, Faculty of Engineering, LTH, LTH Profile areas, LTH Profile Area: Nanoscience and Semiconductor Technology, Lunds universitet, Lunds Tekniska Högskola, LTH profilområden, LTH profilområde: Nanovetenskap och halvledarteknologi, Originator; Lund University, Faculty of Engineering, LTH, LTH Profile areas, LTH Profile Area: Aerosols, Lunds universitet, Lunds Tekniska Högskola, LTH profilområden, LTH profilområde: Aerosoler, Originator; Lund University, Profile areas and other strong research environments, Strategic research areas (SRA), NanoLund: Centre for Nanoscience, Lunds universitet, Profilområden och andra starka forskningsmiljöer, Strategiska forskningsområden (SFO), NanoLund: Centre for Nanoscience, Originator
    • نبذة مختصرة :
      We report a spatially resolved spectroscopic study of the visible chemiluminescence emission from different premixed ammonia-air-oxygen flames stabilized on a laminar flat flame burner, with equivalence ratio ranging from 0.7 to 1.35 and an O2/N2 ratio of 0.4. In the reaction zone of the observed flames, the visible emission was recognized to be the chemiluminescence of excited NH2* radicals, while in the post-flame zone, two types of chemiluminescence were observed: NO2* chemiluminescence dominated in the fuel-lean flames and NH2* chemiluminescence dominated in the fuel-rich flames. The high-resolution spectra of the NO2* and NH2* chemiluminescence in the visible region (400-700 nm) were recorded. The intensity of both spectra increased gradually with wavelength. However, the NO2*-chemiluminescence spectrum appeared to be continuous and unstructured, while the NH2*-chemiluminescence spectrum consisted of groups of distinct emission lines. Based on the spectral feature, the ratios of the integrated chemiluminescence intensities over the 598-603 nm wavelength range to the intensities over the 586-592 nm range and 447-453 nm range were used to sense equivalence ratio. In addition, slightly different colors of the fuel-lean and fuel-rich flames were observed, due to the fact that NO2* chemiluminescence had a relatively stronger signal in the blue region than NH2* chemiluminescence. The difference was used to infer flame equivalence ratio using the flame images recorded by a RGB digital camera, where the ratio of the signal from the red channel to the signal from the blue channel was calculated.