Classical nucleation theory and its application to condensing steam flow calculations

Farhang Bakhtar, JB Young, AJ White, DA Simpson

Research output: Contribution to journalArticle

156 Citations (Scopus)


The paper discusses the classical theory of the homogeneous nucleation of water droplets from supersaturated vapour and its application in predicting condensation in steam nozzles. The first part consists of a review of classical nucleation theory, focusing on the many modifications made to the original Becker-Doring theory and providing some new insights into recent developments. It is concluded that the predictive accuracy required for engineering calculations is not yet attainable with a theory derived from first principles. The areas that require most attention relate to the properties of small molecular clusters and the energy transfer processes in the non-isothermal theory. Experiments in converging-diverging nozzles provide the best means for validation at the very high nucleation rates of interest, but measurements of pressure distribution and the Sauter mean droplet radius are insufficient to provide independent checks on the separate theories of nucleation and droplet growth. Nevertheless, a judicious choice for the nucleation rate equation, in combination with a standard droplet growth model and a suitable equation of state for steam, can provide accurate predictions over a wide range of conditions. The exception is at very low pressures where there is evidence that the droplet growth rate in the nucleation zone is underestimated.
Original languageEnglish
Pages (from-to)1315-1333
Number of pages19
JournalInstitution of Mechanical Engineers. Proceedings. Part C: Journal of Mechanical Engineering Science
Issue number(C12)
Publication statusPublished - 1 Apr 2005


  • two-phase flow
  • steam turbines
  • non-equilibrium
  • wet steam
  • nucleation theory


Dive into the research topics of 'Classical nucleation theory and its application to condensing steam flow calculations'. Together they form a unique fingerprint.

Cite this