CARS Spectra from Lean and Stoichiometric CH(4)-N(2)O Flames
Abstract
Broadband CARS spectra were obtained from both the reaction zone and post-flame region of lean and stoichiometric CH(4)-N(2)O flames. To assess methods of obtaining concentration from broadband spectra, N(2) CARS spectra were obtained from a series of air and argon (AIR/AR) mixtures at room temperature. The concentration of N(2) with good accuracy (6%) was obtained both from fitting the shape of the broadband spectra and from the ratio of the resonant to nonresonant susceptibility. Both methods were utilized in interpreting flame spectra. CARS spectra of both N(2) and N(2)O were obtained from the reaction zone of near 0.3 equivalence ratio (fuel/oxidizer) CH(4)-N(2)O flames. Spectra were obtained from room temperature to near the adiabatic flame temperature. Simultaneous observation of both N(2) and N(2)O spectra allows determination of temperature and concentration of both species from the same point in the flame. The spectra demonstrated the high spatial resolution of CARS. In addition, N(2) CARS spectra were obtained from the post-flame region of 0.3, 0.4, 0.5 and 1.0 CH(4)-N(2)O flames. The N(2) spectra were used to obtain concentration and temperature profiles by a least squares fit to model calculations. The temperatures obtained varied with reactant flow rates. However, at appropriate flow rates, the concentrations and temperatures obtained close to the burner surface were in accord with thermochemical calculation. The temperature and concentration profiles obtained from both N(2) and N(2)O CARS spectra can be used to understand the elementary processes occurring in the CH(4)-N(2)O flames investigated.
Document Details
- Document Type
- Technical Report
- Publication Date
- Mar 01, 1983
- Accession Number
- ADA126653
Entities
People
- L. E. Harris
Organizations
- United States Army Armament Research, Development and Engineering Center