Electric Locomotive for the New York Central Railway

Abstract

A survey is presented of recent studies of homogeneous and heterogeneous nucleation and condensation processes and associated flows. The phenomenological (classical) theory of the quasi-steady droplet-formation model with appropriate correction factors can be made to fit homogeneous nucleation and condensation processes in cloud-chamber, supersonic-nozzle and shock-tube flows. Statistical thermodynamics and numerical methods have made it possible to understand small-cluster formation. Free-molecular techniques have contributed significantly to the study of the kinetic processes of clusterization (especially dimerization) and to dynamic properties of small clusters. Heterogeneous nucleation is considered as an extension of the macroscopic theory of homogeneous nucleation. Considerable contributions are expected to the kinetics of heterogeneous condensation from flows in cloud chambers, supersonic nozzles and shock tubes for macroscopic features and from free-molecular-beam techniques for microscopic properties.