A note on the integral condensation rate

Abstract

A method is presented for numerically calculating the increase of liquid water content due to condensation. It relies on considering the most detailed drop growth equation in the formulae for the time rate of change of number density as well as of liquid water content. It is assumed that the drop spectrum can at any time be described by a specific master function for which a three parametric Gamma function has been chosen. In this way an approximate relation for the liquid water increase by condensation is arrived at which is easily evaluable by simple numeries. In addition, effects by various correction factors considering e.g. a kinetic boundary layer around a drop (Knudsen layer), ventilation or the temperature bias between a drop's surface and its surroundings (Howell factor) are investigated. The results show that in particular the Howell factor may not be approximated and that the curvature term has always to be considered in early stages of condensation growth of drops.

Keywords

• increase of liquid water
• drops
• condensation
• three parametric gamma function
• knudsen layer
• curvature term
• flüssigwassergehalt
• tropfen
• kondensation
• dreiparametrige gammaverteilung
• knudsen schicht
• krümmungsterm