- Author
- Shaddix, C. R. | Harrington, J. E. | Smyth, K. C.
- Title
- Enhanced Soot Formation in Flickering CH4/Air Diffusion Flames.
- Coporate
- National Institute of Standards and Technology, Gaithersburg, MD
- Book or Conf
- American Chemical Society (ACS). Reprints of the Fuel Chemistry Division, 1-8 p., 1994
- Keywords
- soot formation | laminar flames | diffusion flames | extinction | methane | soot
- Identifiers
- laser diagnostics; laser-induced incandescence; scattering; time-varying flame
- Abstract
- Optical methods are used to examine soot production in a co-flowing, axisymmetric CH4/air diffusion flame in which the fuel flow rate is acoustically forced to create a time-varying flowfield. For a particular forcing condition in which tip clipping occurs (0.75 V loudspeaker excitation), elastic scattering of vertically polarized light from the soot particles increases by nearly an order of magnitude with respect to the observed for a steady flame with the same mean fuel flow rate. Peak soot volume fractions, as measured by time-resolved laser extinction/tomography at 632.8 and 454.4 nm and calibrated laser-induced incandescence (LII), show a factor of 4-5 enhancement in this flickering flame. A Mie analysis suggests that most of the enhanced soot production results from the formation of larger particles in the time-varying flowfield.