The general concept of the mean diameter of the disperse phase of an aerosol system, first introduced by Mugele and Evans in 1951, has proven to be a very useful one. In this concept, the proper mean diameter, xp,q, is characterized by a single pair of indices, p and q, which are dependent on the actual type of aerosol system under consideration. This paper re-examines the validity of this concept of mean diameter in heat and mass transfer aerosol systems. The concept is found to be applicable only under a very narrow range of conditions. Attention is then given to a more general definition of a mean diameter, applicable to aerosol heat or mass exchangers. Analyses of these devices shows that the more general mean diameter is a function of the capacity rate ratio, R, and effectiveness of the heat exchanger, ε. Solutions to the governing equations have permitted the mean diameter to be presented graphically as a function of these variables. These solutions are given for two types of particle size distributions, the Rosin-Rammler and the log-probability, and for both parallel-flow and counter-flow heat exchangers. The solutions are, however, restricted to cases where the resistance to heat or mass transfer lies exclusively in the continuous phase.

This content is only available via PDF.
You do not currently have access to this content.