PNNL

Abstract

A Laminar Flow Tube Reactor has been designed and constructed in order to provide an accurate, quantitative measurement of a nucleation rate as a function of supersaturation and temperature. Measurements of nucleation of a supersaturated vapor of dibutylphthalate have been made for the temperature range from -30.3 C to +19.1 C. A thorough analysis of the possible sources of experimental uncertainties (such as defining the correct value of the initial vapor concentration, temperature boundary conditions on the reactor walls, accuracy of the calculations of the thermodynamic parameters of the nucleation zone, and particle concentration measurement) has been provided. Both isothermal and the isobaric nucleation rates have been measured. The experimental data obtained have been compared with measurements of other experimental groups and with theoretical predictions made on the basis of the self-consistency correction nucleation theory. Theoretical analysis based on the first and the second nucleation theorems has been made. The critical cluster size and the excess of internal energy of the critical cluster have been obtained.