The carbonization of the soot precursor aerosol
- Brown Univ., Providence, RI (United States); and others
The soot precursor aerosol is now made clearly evident by contemporary sampling techniques in combination with transmission electron microscopy. These particles are the immediate predecessors of mature, partially dehydrogenated carbonaceous soot aggregates, and recent analytical tests indicate they contain a mixture of polycyclic aromatic hydrocarbons. In this work the kinetics of the conversion of precursor particles to carbonaceous soot aggregates in an ethene coannular diffusion flame is investigated by two methods. In one method the time interval for the conversion of precursor particles to form aggregates is observed by electron microscopy. This interval varies in diluted diffusion flames according to the temperature profile which is measured by thermocouple thermometry. This information is supplemented by the observation of the sudden decrease of the hydrogen mole fraction of soot precursor particles as determined by laser microprobe mass spectrometry. Values of the Arrhenius rate constants are found. In addition, observations of soot formation in shock tube pyrolysis experiments are shown for comparison purposes. Illustrations of the use of carbonization rate data in circumventing soot formation in steady and unsteady combustion are discussed. The importance of oxidizing the precursor aerosol prior to the onset of carbonization is made evident.
- OSTI ID:
- 166544
- Report Number(s):
- CONF-9510126--
- Country of Publication:
- United States
- Language:
- English
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