Friday, March 5, 2004
1:30pm Ð 2:30pm
Fred
C. Gouldin
School
of Mechanical and Aerospace Engineering
Abstract:
Premixed turbulent combustion processes are important in many practical devices including SI engines and new, low emissions gas turbine combustors. In most of the combustors found in these devices chemical reactions are confined to thin reaction sheets or flamelets that are wrinkled and distorted by the turbulent velocity field. Quantitative measures of the degree of this wrinkling and distortion include the probability density functions (PDFs) of the reaction sheet normal vector, of temperature gradients within the reaction sheet and of the reaction sheet displacement speed. These quantities are three dimensional and therefore very difficult to measure.
Two-dimensional imaging methods such as planar Rayleigh and Mie scattering, planar laser induced fluorescence and stereo particle image velocimetry have been applied broadly in turbulent combustion studies. However with the exception of a hand full of parallel plane measurements these studies have been limited to producing two-dimensional data. In this presentation three-dimensional measurements via crossed-plane imaging methods developed at Cornell are described and the results obtained to date are outlined. These results include data on instantaneous reaction sheet normal vectors, temperature gradients and reaction sheet displacement speeds.