| Abstrakt: |
In this work, a detailed combustion mechanism was adopted in order to perform a kinetic analysis of the initiation steps in the spark ignition combustion mechanism of acetone (A), n-butanol (B), ethanol (E) and the blends BE (1:1) and ABE (3:6:1). Autoignition combustion simulations were also performed and the resulting ignition delay times were compared. Simulations showed a spread of ignition delay time values, being the highest value attributed to the ethanol combustion whereas acetone is responsible for the lowest. Simulations suggest that acetone exerts great influence on the ignition delay time of the blend ABE. In the spark ignition simulations, all fuels and blends showed similar combustion profiles, with ignition delay times varying from 3.12 × 10−5 to 1.54 × 10−4 s (butanol and ethanol). The kinetic analysis of the reaction rates suggests that the reaction of alkyl radicals with atomic oxygen, produced from the action of the spark, is of great importance to the initiation of the combustion mechanism, leading to the formation of hydroxyl radicals, which play fundamental role in the reactions of hydrogen abstraction of the fuels. The rates of production of carbon monoxide, aldehydes and NOx were also analyzed in the spark ignition simulations, due to environmental issues. All simulations suggest similar results for the [CO]/[CO2] ratio. The highest production of NOx and aldehydes is related to the acetone combustion, whereas butanol combustion yields the lowest levels of both pollutants. [ABSTRACT FROM AUTHOR] |
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