Homogeneous Nucleation and Growth of Ethanol Drops in Supersonic Flow

Abstract

Condensation of ethanol by homogeneous nucleation of liquid droplets has been studied in a supersonic nozzle. Continuous static pressure measurements on the nozzle centerline and light scattering measurements permit the condensation process to be resolved in detail for comparison with theory. Nucleation rates found in the present work are in general agreement with previous results obtained in diffusion and expansion cloud chambers. It is seen that the predictions of the classical theory of homogeneous nucleation or that of the statistical mechanical theory with the assumptions of Dunning roughly agree with the experimental results. Various terms entering different versions of nucleation theory are given quantitatively. The pressure variations in the flow found beyond the onset point of condensation are used to study droplet growth processes. It is shown that a simple kinetic growth law with a constant mass condensation coefficient describes the condensation process well.

Gasdynamics and homogeneous nucleation

“…(1969) Puzyrewski (1969, Wegener ( 1969) , Roberts ( 1969) , Chmielewski and Sherman (1970) , Clumpner (1970), Barschdorff (1970Barschdorff ( , 1971, Wu ( 1972) , Wegener , Clumpner and Wu ( 1972) , , and Wu ( 1 9 7 4) .…”

“…Many oth er resul ts were studied for H2O and other vapors in the same manner and in general the trends are similar to those of A straight line is noted even when the vapor behavior departs drastically from the perfect gas behavior as seen for the high pressure data of Gyarmathy et al (1973) Finally , gasdynami c methods h ave been app lied just like the cloud chamber to a study of the binary nud eation in the ethanol-water system . Although this subject is outside our present scope , we refer to nozzle experiments discussed by Clumpner (1970) and Wegener et al (1972) , and recent shock tube work by Wu and Belle (1974). This final section will be concerned with quantitative comparisons of computed and observed critical supersaturation.…”

Nonstationary Homogeneous Nucleation

“…4,18); this is confirmed by experiment (Refs. 14,16,17). Of course, variable p will then be identified with the partial pressure of the vapor phase.…”

Modeling of H2O/D2O Condensation in Supersonic Nozzles

“…Supersonic nozzles have been used extensively to investigate particle formation and growth (Stein and Wegener 1967;Wegener 1969;Wegener et al 1972;Moses and Stein 1978;Wyslouzil et al 2000;Heath et al 2002;Khan et al 2003;Kim et al 2004;Tanimura et al 2005;Wyslouzil et al 2007), and, to a limited extent, to investigate nanodroplet structure (Wyslouzil et al 2006). Complementary modeling studies have been conducted for many years in order to better understand particle formation in these devices (Ostwatitsch 1942), to test existing nucleation or droplet growth models (Wegener et al 1972;Moses and Stein 1978;Young 1993;Wyslouzil et al 1994;Lamanna 2000), or to predict appropriate operating conditions for novel nozzle designs .…”

“…Complementary modeling studies have been conducted for many years in order to better understand particle formation in these devices (Ostwatitsch 1942), to test existing nucleation or droplet growth models (Wegener et al 1972;Moses and Stein 1978;Young 1993;Wyslouzil et al 1994;Lamanna 2000), or to predict appropriate operating conditions for novel nozzle designs .…”