CURRENT VISION OF THE NUCLEATION RATE DESCRIPTION PROBLEM

Michael ANISIMOV

Abstract

Theoretical  description and/or  an  experimental  research  of  new phase  embryo  formation kinetics are widely presented in a problem of Atmospheric Aerosol Dynamics.  These problems involve the intensive heat-transfer devises; the natural deposits of methane or carbon dioxide, etc. Nucleation is arising at aerosol generation in the vapor turbines, at vapour cooling in the heat-exchangers or/and at vapour expansion to atmosphere (any injection through piston) and so on. Nucleation is common
phenomenon  for  the  broad  spectrum  of  systems  with phase  transitions  of  the  first  order.   Critical embryo of new phase is treated as small ball (droplet) with uniform density in the Classical Nucleation Theory (CNT) approximation. There is no warranty that the selected version of Nucleation Theory is good enough for the kinetics of hew phase embryos description.  It is assumed that CNT has the best fit to the experimental data even CNT is distinguished among other “universal theories” by the internal consistency  and  simplicity  of  the  axiomatic  statements  only. The  experimental  data  are  crossing usually the CNT predictions.  Thermodynamics consideration comes to the formal corrections to make consistent the next theory version to the next set of experimental data.  It is the ordinary event when statistical  mechanics  is  applied  unreasonable  for  nucleation  phenomenon.    Nucleation  experiment accuracy  has  risen  considerably  during  the  last  half  of  century,  but  it  does  not  lead  to  consistent experimental  results.   Triple points  (lines,  volumes  etc.)  or/and partial  solubility  of components  are producing  the  complicate  topology  of  the  nucleation  rate  surfaces.  That  result  is  not  understood
enough by the scientific community up to now.  An idea of semiempirical design of the nucleation rate surfaces over diagram of phase equilibria is generated over 10 years.  Phase equilibria lines are taken as  a  zero limit  of  nucleation  rate.    Simply  to  say the  nucleation  rate surfaces  arise  from  the phase equilibria lines.  I.e. topologies of zero limits of nucleation rate exist in multiple handbooks for phase equilibria.  That idea can give a considerable effect for series of nucleation problems in Atmospheric Aerosol Dynamics. It is possible to conclude that the parametric versions of nucleation theory can be created for each set of scaled diagram of phase equilibria.  Design of semiempirical presentations of nucleation rate surfaces permits to create some basic set of nucleation theories, which can be used for binary  and  higher  dimension  nucleation  theories.    More  details  of  the  semiempirical  design  of nucleation rate surfaces will be presented.

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