Tomographic Reconstruction of the Local PDFS of Soot Volume Fraction and Temperature.
Tomographic Reconstruction of the Local PDFS of Soot
Volume Fraction and Temperature.
(507 K)
Sivathanu, Y. R.; Hamins, A.; Hagwood, C.; Kashiwagi, T.
Combustion Institute/Central and Western States (USA)
and Combustion Institute/Mexican National Section and
American Flame Research Committee. Combustion
Fundamentals and Applications. Joint Technical Meeting.
Proceedings. April 23-26, 1995, San Antonio, TX, Gore,
J. P., Editor(s), 92-97 pp, 1995.
Keywords:
combustion; soot; volume; temperature; turbulent flames;
diffusion flames; probes; predictive models; equations;
optical pyrometers; nuclear magnetic resonance
Abstract:
Deconvolution of local properties from line-of-sight
measurements is important in a wide variety of
applications such as x-ray tomography, nuclear magnetic
resonance imaging, atmospheric sciences, optical
inteferometry and flow field diagnostics. The Radon
Transforms form the theoretical basis for retrieving
local properties from path integrated measurements under
steady state conditions. These methods have found
wide-spread application in tomographic spectroscopy of
laminar flames. For turbulent flow fields, conventional
deconvolution algorithms cause greater difficulty due to
the transient nature of the phenomena being studied.
Progress has been made in obtaining ultra-fast multiple
angle and multiple ray measurements in a turbulent flow
field over a small time interval. This technique has
limited temporal resolution and suffers from a high
degree of deconvolution noise due to the asymmetric
nature of the instantaneous flow field. Recently, a
discrete probability function (DPF) method was developed
to deconvolute path integrated measurements in order to
obtain the local PDFs of soot volume fractions in
turbulent flames. The objective of this work is to
extend the DPF method to obtain local PDFs of soot
volume fraction and temperature from path integrated
measurements of emission intensities. The deconvolution
method is evaluated by synthetic noise-free data as well
as experimental data obtained using an intrusive optical
pyrometer.
Building and Fire Research Laboratory
National Institute of Standards and Technology
Gaithersburg, MD 20899