Effects of Fuel Absorption on Radiative Heat Transfer in Methanol Pool Fires.
Effects of Fuel Absorption on Radiative Heat Transfer in
Methanol Pool Fires.
Wakatsuki, K.; Jackson, G. S.; Hamins, A.; Nyden, M. R.
Volume 31; Part 2;
Combustion Institute, Symposium (International) on
Combustion, 31st. Proceedings. Volume 31. Part 2.
August 5-11, 2006, Heidelberg, Germany, Combustion
Institute, Pittsburgh, PA, Barlow, R. S.; Sick, V.;
Glarborg, P.; Yetter, R. A., Editor(s)(s), 2573-2580 pp,
combustion; fire research; pool fires; methane; fuels;
FT-IR; radiative heat transfer; methanol; experiments;
Spectrally resolved infrared absorption coefficients of
methanol were measured using high temperature Fourier
transform infrared (FTIR) spectroscopy for a range of
temperatures (up to 1000 K) expected to be within the
fuel rich core of pool fires. Principal absorption band
peaks decreased with increasing temperature. The
spectral region of the dominant C-O stretching peak
causes the integrated Planck mean absorption
coefficient to decrease above 350 K. Unidirectional
radiation intensity along the fire centerline for a 0.3
m diameter methanol pool was calculated using the 1-D
radiative transport equation with the highly resolved
absorption coefficient database of methanol and
combustion products, and gas-phase temperature and
species profiles calculated by NIST's Fire Dynamics
Simulator. The spectrally integrated intensity at the
methanol pool surface was calculated at 12,400 W/m2 sr,
which agreed to within 2% of previously reported
unidirectional radiation intensity measurements.
Intensity calculations with oft-used simplifications for
modeling fuel vapor absorption were compared with the
spectrally resolved, temperature dependent absorption
calculations, and errors with the simplified approaches
for integrated radiation intensity to the pool surface
were as high as 20%. This study suggests that even for
small methanol pool fires, gas-phase fuel absorption
coefficients should have accurate assessments for
calculating radiation heat transfer to the pool surface.