Laboratory Apparatus for the Measurement of Optical Extinction Coefficients of Postflame Soot in the Infrared.
Laboratory Apparatus for the Measurement of Optical
Extinction Coefficients of Postflame Soot in the
Widmann, J. F.; Yang, J. C.; Bundy, M.; Tsai, B. K.;
Mulholland, G. W.
Review of Scientific Instruments, Vol. 74, No. 2,
938-944, February 2003.
soot; radiative heat transfer; smoke
An experimental apparatus for the measurement of optical
extinction coefficients of postflame soot aerosol in the
infrared region of the electromagnetic spectrum is
presented. Reproducible soot aerosol is generated using
a laminar diffusion burner, and the mass concentration
of the aerosol is determined gravimetrically. The
instrument, which utilizes an infrared spectrograph for
the extinction measurements, provides data over the
wavelength range 2.55.0 mum. The infrared spectrograph,
which provides a near-instantaneous measurement of the
incident radiation over a range of wavelengths, is ideal
for applications in which the deposition of soot over
time on the optical windows can interfere with the
measurement. Furthermore, the wavelength dependence of
the extinction coefficient can be determined
independently of the gravimetric measurements, which
represents the dominant source of uncertainty in the
measurement of the mass specific extinction coefficient.
The spectrograph reported herein has been characterized
using a well-characterized sodium heat pipe blackbody,
and the responsivity of the instrument has been
quantified as a function of wavelength.