Tomographic Reconstruction of Probability Density Functions in Turbulent Flames.
Tomographic Reconstruction of Probability Density
Functions in Turbulent Flames.
Vallikul, P.; Goulard, R.; Mavriplis, C.; Nyden, M. R.
Interscience Communications Ltd.; National Institute of
Standards and Technology; Building Research
Establishment; and Society of Fire Protection Engineers;
Swedish National Testing and Research Institute.
Interflam '96. International Interflam Conference, 7th
Proceedings. March 26-28, 1996, Cambridge, England,
Interscience Communications Ltd., London, England,
Franks, C. A.; Grayson, S., Editor(s)(s), 235-243 pp,
fire safety; smoke measurement; turbulent flames;
density effects; algorithms
Local probability density functions (PDF) of absorption
coefficients within turbulent flames have been retrieved
from their multi-angular absorption data of
path-integrated probability density functions via a
series of numerical techniques. First the Filter
Back-Projection (FBP) technique has been used to
reconstruct local moments within the flame then the
moments are transformed to the local PDFs by using the
singular value decomposition (SVD) technique. The FBP
technique transforms the absorption data into the
frequency domain where noisy components can be truncated
while turbulent components are still preserved in the
form of reconstructed moments. The reconstruction
algorithm is tested by using both synthetic and
experimental absorption data. Reconstruction from
synthetic data allows the reconstruction algorithm to be
evaluated independently of path measurement noise. On
the other hand, reconstruction from experimental data
demonstrates the capability of determining the local PDF
analytically within the turbulent flame. Good
reconstruction results are obtained from both cases and
the reconstruction algorithm is justified.