Characterization of the scalar field in turbulent premixed flames by two-point laser induced rayleigh scattering

Ghenaï C., Chauveau C., GÖKALP İ.

32nd Joint Propulsion Conference and Exhibit, 1996, Florida, Amerika Birleşik Devletleri, 1 - 03 Temmuz 1996, ss.1-16, (Tam Metin Bildiri)

  • Yayın Türü: Bildiri / Tam Metin Bildiri
  • Basıldığı Şehir: Florida
  • Basıldığı Ülke: Amerika Birleşik Devletleri
  • Sayfa Sayıları: ss.1-16
  • Orta Doğu Teknik Üniversitesi Adresli: Evet

Özet

One and two-point laser induced Rayleigh scattering techniques have been used to fully characterize the instantaneous density field in turbulent open conical flames of methane-air in the flamelet regime. The instantaneous density information is used to deduce space and time statistics of instantaneous flame fronts along constant progress variable contours. They include the integral and dissipation time scales of the scalar field, flamelet crossing frequencies, transit times and convection velocities. The mean flamelet wrinkling scale and the mean flamelet orientation angle are also deduced. These flamelet space, time and velocity characteristics are used to implement some existing flame surface density models and to compare with some DNS predictions. The results show that the integral and dissipation time scales of the scalar field (the progress variable c) vary through the flame brush and decrease with increasing . The characteristic flamelet wrinkling scale, determined directly from two- point measurements also decrease with increasing . The flamelet convection velocity along iso- contours, and the flamelet normal velocity have been found independent of . The mean flamelet orientation angle is also independent of and equal to 0.7, as also found by DNS. The experimental results have been used to implement the BMCL closures for the mean rate of creation of products, both for their temporal and spatial versions.