Theoretical and Computational Studies of Nucleation in Supercritical Fuels
Abstract
The goal of this research is to improve basic understanding of how thermodynamics and nucleation kinetics influence the deposit of pyrolytic products from supercritical fuels. The precipitation of picene from supercritical methylcyclohexane was investigated theoretically, under the assumptions of both thermodynamic and kinetic control. The kinetic calculations indicated that a negligible amount of deposits were formed as a result of friction-driven depressurization in tubular flow. However, the presence of small amounts of particulate impurities dramatically enhanced the rate of deposit formation. For isobaric cooling conditions, the rate of deposit formation was found to depend sensitively on whether the mixture entered the retrograde region or not. In the retrograde region where solubility decreases with increasing temperature, isobaric cooling was found to suppress deposit formation. The time evolution of isolated quiescent droplets exposed to an excess of partially miscible compressed solvent was investigated under sub-critical conditions. Over a wide range of conditions the calculations showed appreciable droplet swelling, followed by evaporation. An aerosol dynamics code was combined with mass, momentum, energy balances and equation of state calculations to yield the evolution of the particle size during steady, one-dimensional friction-driven expansions of a supercritical fluid containing a dissolved solute.
Document Details
- Document Type
- Technical Report
- Publication Date
- Aug 21, 1998
- Accession Number
- ADA353446
Entities
People
- Pablo G. Debenedetti
Organizations
- Princeton University