A comparison of velocity and scalar spectra in premixed turbulent flames
Scalar (intermittency) and velocity spectra in premixed methane/air turbulent v-flames and stagnation flow stabilized flames have been measured using laser light Mie scattering and laser Doppler anemometry techniques. To compare the velocity spectra of the oblique v-flame with those of the normal stagnation flames, the velocity data for v-flames are transformed to obtain the spectra of the velocity components normal and tangential to the oblique flame zone. In both configurations, the spectra of the normal velocity components are similar to the corresponding scalar spectra. The most energetic frequencies are consistent with the flame passage frequencies demonstrating clearly that the velocity and scalar spectra are strongly coupled. However, the most energetic frequencies are about an order of magnitude higher in the v-flame than in the stagnation flames even though the incidence turbulence of the two flames are similar. Since this difference does not seem to be proportional to the difference in the mean velocities, our results imply that the spatial scales in the two flame zones are not the same.
- Research Organization:
- Lawrence Berkeley Lab., CA (USA); California Univ., Berkeley (USA). Dept. of Mechanical Engineering; Centre National de la Recherche Scientifique, 45 - Orleans-la-Source (France). Centre de Recherches sur la Chimie de Combustion et des Hautes Temperatures
- DOE Contract Number:
- AC03-76SF00098
- OSTI ID:
- 6366962
- Report Number(s):
- LBL-23521; CONF-870989-1; ON: DE87011099
- Country of Publication:
- United States
- Language:
- English
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