摘要：

Our understanding of soot formation has evolved from an empirical,

phenomenological description to an age of quantitative modeling using

detailed chemistry and aerosol dynamics.  Yet there still exist significant

fundamental gaps.  This talk will be focused a discussion of several

fundamental issues critical to the development of the next-generation,

kinetic model for soot formation.  The first issue concerns the multiplicity

of the reaction pathways leading to soot precursor formation.  This

multiplicity stems from the varying and often strong sensitivity for the

formation of polycyclic aromatic hydrocarbons with respect to local and

global combustion condition and fuel components, and in the case of

real-fuel combustion, both can vary widely.  Previous research shows that

the reaction kinetics of PAHs can be extremely sensitive to main flame

chemistry.  While the kinetic uncertainties in the basic flame chemistry

will persist for a long time and considering the reaction path multiplicity,

the current modeling philosophy and capability may not be the most

productive path to deriving a broadly predictive chemistry model for PAH

formation in flames.  In addition to this difficulty, recent work also

suggests that with entropy resistance, the dispersion and electrostatic

binding forces among the most stable PAH molecules are too weak to allow

them to bind efficiently at combustion temperatures.  Thus, the mechanism of

soot nucleation remains largely undefined.  Possible solutions to the above

problems will be suggested and discussed.