ISSN:
0721-3115
Schlagwort(e):
Chemistry
;
Polymer and Materials Science
Quelle:
Wiley InterScience Backfile Collection 1832-2000
Thema:
Chemie und Pharmazie
,
Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
Notizen:
Nitromethane (CH3NO2) Pool Fire Flames have been investigated analysing both, the radiation emitted from intermediate combustion radicals (diatomic molecules) in the ultraviolet (UV) and visible (VIS) spectral range, and the near infrared spectra dominated by broad water bands. Comparing the UV/VIS spectra to calculated band profiles, rotational and vibrational temperatures (Trot, Tvib) of OH, NH and CN have been determined. At local thermal equilibrium Trot and Tvib must be equal. The determined temperatures show that the OH and NH emissions originate from pure thermal excitation (Trot = Tvib = 2300 K-2380 K) but the CN emissions show additionally a chemical excitation indicated by different vibrational and rotational temperatures in the Boltzman factor (Trot = 2100 K, Tvib = 4300 K). For a more detailed study of the flame, the emission of OH radicals has been investigated more extensively by monitoring a two-dimensional rotational temperature and emissivity profile. In cooler flame regions, the observed spectra are dominated by the near infrared radiation emitted from stable combustion products like water and carbon dioxide. Therefore, NIR spectra (1000 nm to 2500 nm) have been compared to broad band profiles calculated with a self-developed code basing on the data of the ‘Handbook of Infrared Radiation of Combustion Gases’. The flame temperatures obtained by this method range from 1800 K to 1900 K. The results are correlated to flames of methane and nitrogen oxide which emit similar spectra indicating similar reaction mechanisms in the gaseous phase.
Zusätzliches Material:
7 Ill.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1002/prep.19970220316
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