MODELING CHAR OXIDATION AS A FUNCTION OF PRESSURE ...

varied between 1000 and 1500 K, with 5% to 21% oxygen in the bulk gas, resulting in
average particle temperatures up to and 2100 K and burnout from 15% to 96% (daf).
Approach
Two injection probes, one cooled and the other uncooled, were used during the
tests. Because of the large heat loss and the greater particle dispersion associated with the
cooled probe, only the experiments using the uncooled probe were considered in this
study. In addition, the majority of the experiments used a reaction length between 6.5 –
12.5 cm while a few experiments used reaction length as short as 4 cm. Although the
particles were pre-heated in the uncooled probe, there existed a short transient period in
which ignition and momentum transfer (between the particle and the secondary gas)
occurred. For experiments using a very short reaction length, this transition period may
affect the accurate calculation of reaction rates. Therefore, the experiments with a
reaction length shorter than 6 cm were not considered in this study. After the above
screening, 45 experiments were modeled in this study (see Table 5).
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