ABSTRACT
For modest temperature and pressure levels, single species fl uids may be reasonably analyzed as variable density ideal gases or as constant density liquids. For wide temperature and pressure ranges and for liquid/ vapor coexistent conditions, single species fl uids must be analyzed with real-fl uid thermodynamic properties. Multicomponent fl uids may be analyzed the same way, if they do not react. If conditions are such that the multicomponent fl uids react very fast, a condition of local chemical equilibrium may exist in the fl owfi eld. If the chemical reactions occur at
a rate comparable to the local residence time in the fl ow, the reactions are controlled by fi nite-rate chemical reactions. For the purposes of the analyses described herein, multicomponent fl uids are always assumed to be intimately mixed at a given location. Th is means that at a given point, the convection, diff usion, and reactions of the various species are to be predicted, whereas local unmixedness on a molecular scale is not considered. At this time unmixedness can only be described with experimentally measured or arbitrarily postulated probability distribution functions, not with the continuum conservation equations.
