On the Growth of Steam Droplets Formed in a Laval Nozzle Using Both Static Pressure and Light Scattering Measurements

A series of experiments on steam condensation have been made in a Laval nozzle over a variety of starting conditions such that the onset of condensation occurs in the range −40 to 40°C (233–313 K). The homogeneous nucleation and growth of the new phase are documented with both static pressure and laser light scattering. Since even at onset the majority of the condensed phase is due to droplet growth the nucleation and growth are coupled and the availability of two measured quantities is helpful in comparing a particular combination of nucleation rate and growth law. For detailed calculations on one of the experiments there is excellent agreement with both measurements throughout the condensation zone and theoretical calculations using the classical nucleation rate expression due to Volmer and droplet growth laws due to Gyarmathy and Hill in which thermal and mass accommodation coefficients are near unity.